Project import generated by Copybara.

GitOrigin-RevId: da3cb82c964457b1c719c915a48e545b980af64b
2020-04-06 21:28:19 -07:00 · 2020-04-06 19:14:13 -07:00 · 2020-03-20 15:28:51 -07:00 · 2020-03-10 18:14:25 -07:00 · 2020-03-02 10:35:07 -08:00 · 2020-02-10 14:13:25 -08:00
957 changed files with 118601 additions and 7622 deletions
@@ -3,7 +3,7 @@
 # Basic build settings
 build --jobs 128
 build --define='absl=1'
-build --cxxopt='-std=c++11'
+build --cxxopt='-std=c++14'
 build --copt='-Wno-sign-compare'
 build --copt='-Wno-unused-function'
 build --copt='-Wno-uninitialized'
@@ -12,13 +12,21 @@ build --copt='-Wno-comment'
 build --copt='-Wno-return-type'
 build --copt='-Wno-unused-local-typedefs'
 build --copt='-Wno-ignored-attributes'
-# Temporarily set the incompatiblity flag for Bazel 0.27.0 and above
-build --incompatible_disable_deprecated_attr_params=false
+
+# Tensorflow needs remote repo
+build --experimental_repo_remote_exec

 # Sets the default Apple platform to macOS.
 build --apple_platform_type=macos

+# Allow debugging with XCODE
+build --apple_generate_dsym
+
 # Android configs.
+# Note: the documentation tells us to use @androidndk//:default_crosstool, but
+# the automatic configuration transition uses //external:android/crosstool.
+# Using it here works and spares us from having two different config_settings
+# for Android.
 build:android --crosstool_top=//external:android/crosstool
 build:android --host_crosstool_top=@bazel_tools//tools/cpp:toolchain
 build:android --linkopt=-landroid
@@ -24,26 +24,31 @@ ENV DEBIAN_FRONTEND=noninteractive
 RUN apt-get update && apt-get install -y --no-install-recommends \
        build-essential \
        ca-certificates \
+        curl \
        git \
        wget \
        unzip \
        python \
        python-pip \
+        python3-pip \
        libopencv-core-dev \
        libopencv-highgui-dev \
        libopencv-imgproc-dev \
        libopencv-video-dev \
+        libopencv-calib3d-dev \
+        libopencv-features2d-dev \
        software-properties-common && \
    add-apt-repository -y ppa:openjdk-r/ppa && \
-    apt-get update && apt-get install -y openjdk-11-jdk && \
+    apt-get update && apt-get install -y openjdk-8-jdk && \
    apt-get clean && \
    rm -rf /var/lib/apt/lists/*

 RUN pip install --upgrade setuptools
 RUN pip install future
+RUN pip3 install six

 # Install bazel
-ARG BAZEL_VERSION=0.26.1
+ARG BAZEL_VERSION=2.0.0
 RUN mkdir /bazel && \
    wget --no-check-certificate -O /bazel/installer.sh "https://github.com/bazelbuild/bazel/releases/download/${BAZEL_VERSION}/b\
 azel-${BAZEL_VERSION}-installer-linux-x86_64.sh" && \
@@ -1,15 +1,36 @@
 ![MediaPipe](mediapipe/docs/images/mediapipe_small.png?raw=true "MediaPipe logo")
 =======================================================================

-[MediaPipe](http://mediapipe.dev) is a framework for building multimodal (eg. video, audio, any time series data) applied ML pipelines. With MediaPipe, a perception pipeline can be built as a graph of modular components, including, for instance, inference models (e.g., TensorFlow, TFLite) and media processing functions.
+[MediaPipe](http://mediapipe.dev) is a framework for building multimodal (eg. video, audio, any time series data), cross platform (i.e Android, iOS, web, edge devices) applied ML pipelines. With MediaPipe, a perception pipeline can be built as a graph of modular components, including, for instance, inference models (e.g., TensorFlow, TFLite) and media processing functions.

 ![Real-time Face Detection](mediapipe/docs/images/realtime_face_detection.gif)

+> "<em>MediaPipe has made it extremely easy to build our 3D person pose reconstruction demo app, facilitating accelerated neural network inference on device and synchronization of our result visualization with the video capture stream. Highly recommended!</em>" - George Papandreou, CTO, [Ariel AI](https://arielai.com)
+
+## ML Solutions in MediaPipe
+
+* [Face Detection](mediapipe/docs/face_detection_mobile_gpu.md) [[Web Demo]](https://viz.mediapipe.dev/runner/demos/face_detection/face_detection.html)
+* [Multi-hand Tracking](mediapipe/docs/multi_hand_tracking_mobile_gpu.md)
+* [Hand Tracking](mediapipe/docs/hand_tracking_mobile_gpu.md) [[Web Demo]](https://viz.mediapipe.dev/runner/demos/hand_tracking/hand_tracking.html)
+* [Hair Segmentation](mediapipe/docs/hair_segmentation_mobile_gpu.md) [[Web Demo]](https://viz.mediapipe.dev/runner/demos/hair_segmentation/hair_segmentation.html)
+* [Object Detection](mediapipe/docs/object_detection_mobile_gpu.md)
+* [Object Detection and Tracking](mediapipe/docs/object_tracking_mobile_gpu.md)
+* [Objectron: 3D Object Detection and Tracking](mediapipe/docs/objectron_mobile_gpu.md)
+* [AutoFlip](mediapipe/docs/autoflip.md)
+
+![face_detection](mediapipe/docs/images/mobile/face_detection_android_gpu_small.gif)
+![multi-hand_tracking](mediapipe/docs/images/mobile/multi_hand_tracking_android_gpu_small.gif)
+![hand_tracking](mediapipe/docs/images/mobile/hand_tracking_3d_android_gpu_small.gif)
+![hair_segmentation](mediapipe/docs/images/mobile/hair_segmentation_android_gpu_small.gif)
+![object_tracking](mediapipe/docs/images/mobile/object_tracking_android_gpu_small.gif)
+
 ## Installation
 Follow these [instructions](mediapipe/docs/install.md).

 ## Getting started
-See mobile and desktop [examples](mediapipe/docs/examples.md).
+See mobile, desktop and Google Coral [examples](mediapipe/docs/examples.md).
+
+Check out some web demos [[Edge detection]](https://viz.mediapipe.dev/runner/demos/edge_detection/edge_detection.html) [[Face detection]](https://viz.mediapipe.dev/runner/demos/face_detection/face_detection.html) [[Hand Tracking]](https://viz.mediapipe.dev/runner/demos/hand_tracking/hand_tracking.html)

 ## Documentation
 [MediaPipe Read-the-Docs](https://mediapipe.readthedocs.io/) or [docs.mediapipe.dev](https://docs.mediapipe.dev)
@@ -19,17 +40,33 @@ Check out the [Examples page](https://mediapipe.readthedocs.io/en/latest/example
 ## Visualizing MediaPipe graphs
 A web-based visualizer is hosted on [viz.mediapipe.dev](https://viz.mediapipe.dev/). Please also see instructions [here](mediapipe/docs/visualizer.md).

-## Community forum
-*  [Discuss](https://groups.google.com/forum/#!forum/mediapipe) - General community discussion around MediaPipe
+## Videos
+*  [YouTube Channel](https://www.youtube.com/channel/UCObqmpuSMx-usADtL_qdMAw)

 ## Publications
+* [MediaPipe Objectron: Real-time 3D Object Detection on Mobile Devices](https://mediapipe.page.link/objectron-aiblog)
+* [AutoFlip: An Open Source Framework for Intelligent Video Reframing](https://mediapipe.page.link/autoflip)
+* [Google Developer Blog: MediaPipe on the Web](https://mediapipe.page.link/webdevblog)
+* [Google Developer Blog: Object Detection and Tracking using MediaPipe](https://mediapipe.page.link/objecttrackingblog)
+* [On-Device, Real-Time Hand Tracking with MediaPipe](https://ai.googleblog.com/2019/08/on-device-real-time-hand-tracking-with.html)
 * [MediaPipe: A Framework for Building Perception Pipelines](https://arxiv.org/abs/1906.08172)

 ## Events
-[Open sourced at CVPR 2019](https://sites.google.com/corp/view/perception-cv4arvr/mediapipe) on June 17~20 in Long Beach, CA
+* [AI Nextcon 2020, 12-16 Feb 2020, Seattle](http://aisea20.xnextcon.com/)
+* [MediaPipe Madrid Meetup, 16 Dec 2019](https://www.meetup.com/Madrid-AI-Developers-Group/events/266329088/)
+* [MediaPipe London Meetup, Google 123 Building, 12 Dec 2019](https://www.meetup.com/London-AI-Tech-Talk/events/266329038)
+* [ML Conference, Berlin, 11 Dec 2019](https://mlconference.ai/machine-learning-advanced-development/mediapipe-building-real-time-cross-platform-mobile-web-edge-desktop-video-audio-ml-pipelines/)
+* [MediaPipe Berlin Meetup, Google Berlin, 11 Dec 2019](https://www.meetup.com/Berlin-AI-Tech-Talk/events/266328794/)
+* [The 3rd Workshop on YouTube-8M Large Scale Video Understanding Workshop](https://research.google.com/youtube8m/workshop2019/index.html) Seoul, Korea ICCV 2019
+* [AI DevWorld 2019](https://aidevworld.com) on Oct 10 in San Jose, California
+* [Google Industry Workshop at ICIP 2019](http://2019.ieeeicip.org/?action=page4&id=14#Google) [Presentation](https://docs.google.com/presentation/d/e/2PACX-1vRIBBbO_LO9v2YmvbHHEt1cwyqH6EjDxiILjuT0foXy1E7g6uyh4CesB2DkkEwlRDO9_lWfuKMZx98T/pub?start=false&loop=false&delayms=3000&slide=id.g556cc1a659_0_5) on Sept 24 in Taipei, Taiwan
+* [Open sourced at CVPR 2019](https://sites.google.com/corp/view/perception-cv4arvr/mediapipe) on June 17~20 in Long Beach, CA
+
+## Community forum
+*  [Discuss](https://groups.google.com/forum/#!forum/mediapipe) - General community discussion around MediaPipe

 ## Alpha Disclaimer
-MediaPipe is currently in alpha for v0.6. We are still making breaking API changes and expect to get to stable API by v1.0.
+MediaPipe is currently in alpha for v0.7. We are still making breaking API changes and expect to get to stable API by v1.0.

 ## Contributing
 We welcome contributions. Please follow these [guidelines](./CONTRIBUTING.md).
@@ -2,27 +2,38 @@ workspace(name = "mediapipe")

 load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")

-skylib_version = "0.8.0"
+skylib_version = "0.9.0"
 http_archive(
    name = "bazel_skylib",
    type = "tar.gz",
-    url = "https://github.com/bazelbuild/bazel-skylib/releases/download/{}/bazel-skylib.{}.tar.gz".format (skylib_version, skylib_version),
-    sha256 = "2ef429f5d7ce7111263289644d233707dba35e39696377ebab8b0bc701f7818e",
+    url = "https://github.com/bazelbuild/bazel-skylib/releases/download/{}/bazel_skylib-{}.tar.gz".format (skylib_version, skylib_version),
+    sha256 = "1dde365491125a3db70731e25658dfdd3bc5dbdfd11b840b3e987ecf043c7ca0",
 )
 load("@bazel_skylib//lib:versions.bzl", "versions")
-versions.check(minimum_bazel_version = "0.23.0")
+versions.check(minimum_bazel_version = "2.0.0")

-# ABSL cpp library.
+
+# ABSL cpp library lts_2020_02_25
 http_archive(
    name = "com_google_absl",
-    # Head commit on 2019-04-12.
-    # TODO: Switch to the latest absl version when the problem gets
-    # fixed.
    urls = [
-        "https://github.com/abseil/abseil-cpp/archive/a02f62f456f2c4a7ecf2be3104fe0c6e16fbad9a.tar.gz",
+        "https://github.com/abseil/abseil-cpp/archive/20200225.tar.gz",
    ],
-    sha256 = "d437920d1434c766d22e85773b899c77c672b8b4865d5dc2cd61a29fdff3cf03",
-    strip_prefix = "abseil-cpp-a02f62f456f2c4a7ecf2be3104fe0c6e16fbad9a",
+    # Remove after https://github.com/abseil/abseil-cpp/issues/326 is solved.
+    patches = [
+        "@//third_party:com_google_absl_f863b622fe13612433fdf43f76547d5edda0c93001.diff"
+    ],
+    patch_args = [
+        "-p1",
+    ],
+    strip_prefix = "abseil-cpp-20200225",
+    sha256 = "728a813291bdec2aa46eab8356ace9f75ac2ed9dfe2df5ab603c4e6c09f1c353"
+)
+
+http_archive(
+    name = "rules_cc",
+    strip_prefix = "rules_cc-master",
+    urls = ["https://github.com/bazelbuild/rules_cc/archive/master.zip"],
 )

 # GoogleTest/GoogleMock framework. Used by most unit-tests.
@@ -58,6 +69,20 @@ http_archive(
    sha256 = "267103f8a1e9578978aa1dc256001e6529ef593e5aea38193d31c2872ee025e8",
    strip_prefix = "glog-0.3.5",
    build_file = "@//third_party:glog.BUILD",
+    patches = [
+        "@//third_party:com_github_glog_glog_9779e5ea6ef59562b030248947f787d1256132ae.diff"
+    ],
+    patch_args = [
+        "-p1",
+    ],
+)
+
+# easyexif
+http_archive(
+    name = "easyexif",
+    url = "https://github.com/mayanklahiri/easyexif/archive/master.zip",
+    strip_prefix = "easyexif-master",
+    build_file = "@//third_party:easyexif.BUILD",
 )

 # libyuv
@@ -67,11 +92,13 @@ http_archive(
    build_file = "@//third_party:libyuv.BUILD",
 )

+# Note: protobuf-javalite is no longer released as a separate download, it's included in the main Java download.
+# ...but the Java download is currently broken, so we use the "source" download.
 http_archive(
    name = "com_google_protobuf_javalite",
-    sha256 = "79d102c61e2a479a0b7e5fc167bcfaa4832a0c6aad4a75fa7da0480564931bcc",
-    strip_prefix = "protobuf-384989534b2246d413dbcd750744faab2607b516",
-    urls = ["https://github.com/google/protobuf/archive/384989534b2246d413dbcd750744faab2607b516.zip"],
+    sha256 = "a79d19dcdf9139fa4b81206e318e33d245c4c9da1ffed21c87288ed4380426f9",
+    strip_prefix = "protobuf-3.11.4",
+    urls = ["https://github.com/protocolbuffers/protobuf/archive/v3.11.4.tar.gz"],
 )

 http_archive(
@@ -91,30 +118,42 @@ http_archive(
    ],
 )

-# 2019-08-15
-_TENSORFLOW_GIT_COMMIT = "67def62936e28f97c16182dfcc467d8d1cae02b4"
-_TENSORFLOW_SHA256= "ddd4e3c056e7c0ff2ef29133b30fa62781dfbf8a903e99efb91a02d292fa9562"
+# 2020-04-01
+_TENSORFLOW_GIT_COMMIT = "805e47cea96c7e8c6fccf494d40a2392dc99fdd8"
+_TENSORFLOW_SHA256= "9ee3ae604c2e1345ac60345becee6d659364721513f9cb8652eb2e7138320ca5"
 http_archive(
    name = "org_tensorflow",
    urls = [
      "https://mirror.bazel.build/github.com/tensorflow/tensorflow/archive/%s.tar.gz" % _TENSORFLOW_GIT_COMMIT,
      "https://github.com/tensorflow/tensorflow/archive/%s.tar.gz" % _TENSORFLOW_GIT_COMMIT,
    ],
-    strip_prefix = "tensorflow-%s" % _TENSORFLOW_GIT_COMMIT,
-    sha256 = _TENSORFLOW_SHA256,
    patches = [
-        "@//third_party:tensorflow_065c20bf79253257c87bd4614bb9a7fdef015cbb.diff",
-        "@//third_party:tensorflow_f67fcbefce906cd419e4657f0d41e21019b71abd.diff",
+        "@//third_party:org_tensorflow_compatibility_fixes.diff",
+        "@//third_party:org_tensorflow_protobuf_updates.diff",
    ],
    patch_args = [
        "-p1",
    ],
+    strip_prefix = "tensorflow-%s" % _TENSORFLOW_GIT_COMMIT,
+    sha256 = _TENSORFLOW_SHA256,
 )

 load("@org_tensorflow//tensorflow:workspace.bzl", "tf_workspace")
 tf_workspace(tf_repo_name = "org_tensorflow")

-# Please run $ sudo apt-get install libopencv-dev
+http_archive(
+    name = "ceres_solver",
+    url = "https://github.com/ceres-solver/ceres-solver/archive/1.14.0.zip",
+    patches = [
+        "@//third_party:ceres_solver_9bf9588988236279e1262f75d7f4d85711dfa172.diff"
+    ],
+    patch_args = [
+        "-p1",
+    ],
+    strip_prefix = "ceres-solver-1.14.0",
+    sha256 = "5ba6d0db4e784621fda44a50c58bb23b0892684692f0c623e2063f9c19f192f1"
+)
+
 new_local_repository(
    name = "linux_opencv",
    build_file = "@//third_party:opencv_linux.BUILD",
@@ -127,7 +166,6 @@ new_local_repository(
    path = "/usr"
 )

-# Please run $ brew install opencv
 new_local_repository(
    name = "macos_opencv",
    build_file = "@//third_party:opencv_macos.BUILD",
@@ -142,11 +180,10 @@ new_local_repository(

 http_archive(
    name = "android_opencv",
-    sha256 = "056b849842e4fa8751d09edbb64530cfa7a63c84ccd232d0ace330e27ba55d0b",
    build_file = "@//third_party:opencv_android.BUILD",
    strip_prefix = "OpenCV-android-sdk",
    type = "zip",
-    url = "https://github.com/opencv/opencv/releases/download/4.1.0/opencv-4.1.0-android-sdk.zip",
+    url = "https://github.com/opencv/opencv/releases/download/3.4.3/opencv-3.4.3-android-sdk.zip",
 )

 # After OpenCV 3.2.0, the pre-compiled opencv2.framework has google protobuf symbols, which will
@@ -161,74 +198,6 @@ http_archive(
    url = "https://github.com/opencv/opencv/releases/download/3.2.0/opencv-3.2.0-ios-framework.zip",
 )

-RULES_JVM_EXTERNAL_TAG = "2.2"
-RULES_JVM_EXTERNAL_SHA = "f1203ce04e232ab6fdd81897cf0ff76f2c04c0741424d192f28e65ae752ce2d6"
-
-http_archive(
-    name = "rules_jvm_external",
-    strip_prefix = "rules_jvm_external-%s" % RULES_JVM_EXTERNAL_TAG,
-    sha256 = RULES_JVM_EXTERNAL_SHA,
-    url = "https://github.com/bazelbuild/rules_jvm_external/archive/%s.zip" % RULES_JVM_EXTERNAL_TAG,
-)
-
-load("@rules_jvm_external//:defs.bzl", "maven_install")
-
-maven_install(
-    artifacts = [
-        "androidx.annotation:annotation:aar:1.1.0",
-        "androidx.appcompat:appcompat:aar:1.1.0-rc01",
-        "androidx.constraintlayout:constraintlayout:aar:1.1.3",
-        "androidx.core:core:aar:1.1.0-rc03",
-        "androidx.legacy:legacy-support-v4:aar:1.0.0",
-        "androidx.recyclerview:recyclerview:aar:1.1.0-beta02",
-        "com.google.android.material:material:aar:1.0.0-rc01",
-    ],
-    repositories = ["https://dl.google.com/dl/android/maven2"],
-)
-
-maven_server(
-    name = "google_server",
-    url = "https://dl.google.com/dl/android/maven2",
-)
-
-maven_jar(
-    name = "androidx_lifecycle",
-    artifact = "androidx.lifecycle:lifecycle-common:2.0.0",
-    sha1 = "e070ffae07452331bc5684734fce6831d531785c",
-    server = "google_server",
-)
-
-maven_jar(
-     name = "androidx_concurrent_futures",
-     artifact = "androidx.concurrent:concurrent-futures:1.0.0-alpha03",
-     sha1 = "b528df95c7e2fefa2210c0c742bf3e491c1818ae",
-     server = "google_server",
-)
-
-maven_jar(
-    name = "com_google_guava_android",
-    artifact = "com.google.guava:guava:27.0.1-android",
-    sha1 = "b7e1c37f66ef193796ccd7ea6e80c2b05426182d",
-)
-
-maven_jar(
-    name = "com_google_common_flogger",
-    artifact = "com.google.flogger:flogger:0.3.1",
-    sha1 = "585030fe1ec709760cbef997a459729fb965df0e",
-)
-
-maven_jar(
-    name = "com_google_common_flogger_system_backend",
-    artifact = "com.google.flogger:flogger-system-backend:0.3.1",
-    sha1 = "287b569d76abcd82f9de87fe41829fbc7ebd8ac9",
-)
-
-maven_jar(
-    name = "com_google_code_findbugs",
-    artifact = "com.google.code.findbugs:jsr305:3.0.2",
-    sha1 = "25ea2e8b0c338a877313bd4672d3fe056ea78f0d",
-)
-
 # You may run setup_android.sh to install Android SDK and NDK.
 android_ndk_repository(
    name = "androidndk",
@@ -240,14 +209,13 @@ android_sdk_repository(

 # iOS basic build deps.

-load("@bazel_tools//tools/build_defs/repo:git.bzl", "git_repository")
-
-git_repository(
+http_archive(
    name = "build_bazel_rules_apple",
-    remote = "https://github.com/bazelbuild/rules_apple.git",
-    tag = "0.18.0",
+    sha256 = "7a7afdd4869bb201c9352eed2daf37294d42b093579b70423490c1b4d4f6ce42",
+    url = "https://github.com/bazelbuild/rules_apple/releases/download/0.19.0/rules_apple.0.19.0.tar.gz",
    patches = [
-        "@//third_party:rules_apple_c0863d0596ae6b769a29fa3fb72ff036444fd249.diff",
+        # Bypass checking ios unit test runner when building MP ios applications.
+        "@//third_party:build_bazel_rules_apple_bypass_test_runner_check.diff"
    ],
    patch_args = [
        "-p1",
@@ -284,3 +252,50 @@ http_archive(
    strip_prefix = "google-toolbox-for-mac-2.2.1",
    build_file = "@//third_party:google_toolbox_for_mac.BUILD",
 )
+
+# Maven dependencies.
+
+RULES_JVM_EXTERNAL_TAG = "3.2"
+RULES_JVM_EXTERNAL_SHA = "82262ff4223c5fda6fb7ff8bd63db8131b51b413d26eb49e3131037e79e324af"
+
+http_archive(
+    name = "rules_jvm_external",
+    strip_prefix = "rules_jvm_external-%s" % RULES_JVM_EXTERNAL_TAG,
+    sha256 = RULES_JVM_EXTERNAL_SHA,
+    url = "https://github.com/bazelbuild/rules_jvm_external/archive/%s.zip" % RULES_JVM_EXTERNAL_TAG,
+)
+
+load("@rules_jvm_external//:defs.bzl", "maven_install")
+
+# Important: there can only be one maven_install rule. Add new maven deps here.
+maven_install(
+    name = "maven",
+    artifacts = [
+        "junit:junit:4.12",
+        "androidx.test.espresso:espresso-core:3.1.1",
+        "org.hamcrest:hamcrest-library:1.3",
+        "androidx.concurrent:concurrent-futures:1.0.0-alpha03",
+        "androidx.lifecycle:lifecycle-common:2.2.0",
+        "androidx.annotation:annotation:aar:1.1.0",
+        "androidx.appcompat:appcompat:aar:1.1.0-rc01",
+        "androidx.camera:camera-core:aar:1.0.0-alpha06",
+        "androidx.camera:camera-camera2:aar:1.0.0-alpha06",
+        "androidx.constraintlayout:constraintlayout:aar:1.1.3",
+        "androidx.core:core:aar:1.1.0-rc03",
+        "androidx.legacy:legacy-support-v4:aar:1.0.0",
+        "androidx.recyclerview:recyclerview:aar:1.1.0-beta02",
+        "com.google.android.material:material:aar:1.0.0-rc01",
+        "com.google.code.findbugs:jsr305:3.0.2",
+        "com.google.flogger:flogger-system-backend:0.3.1",
+        "com.google.flogger:flogger:0.3.1",
+        "com.google.guava:guava:27.0.1-android",
+    ],
+    repositories = [
+        "https://jcenter.bintray.com",
+        "https://maven.google.com",
+        "https://dl.google.com/dl/android/maven2",
+        "https://repo1.maven.org/maven2",
+    ],
+    fetch_sources = True,
+    version_conflict_policy = "pinned",
+)
@@ -14,6 +14,9 @@

 licenses(["notice"])  # Apache 2.0

+# Note: yes, these need to use "//external:android/crosstool", not
+# @androidndk//:default_crosstool.
+
 config_setting(
    name = "android",
    values = {"crosstool_top": "//external:android/crosstool"},
@@ -9,6 +9,7 @@
    "mediapipe/examples/ios/facedetectiongpu/BUILD",
    "mediapipe/examples/ios/handdetectiongpu/BUILD",
    "mediapipe/examples/ios/handtrackinggpu/BUILD",
+    "mediapipe/examples/ios/multihandtrackinggpu/BUILD",
    "mediapipe/examples/ios/objectdetectioncpu/BUILD",
    "mediapipe/examples/ios/objectdetectiongpu/BUILD"
  ],
@@ -18,6 +19,7 @@
    "//mediapipe/examples/ios/facedetectiongpu:FaceDetectionGpuApp",
    "//mediapipe/examples/ios/handdetectiongpu:HandDetectionGpuApp",
    "//mediapipe/examples/ios/handtrackinggpu:HandTrackingGpuApp",
+    "//mediapipe/examples/ios/multihandtrackinggpu:MultiHandTrackingGpuApp",
    "//mediapipe/examples/ios/objectdetectioncpu:ObjectDetectionCpuApp",
    "//mediapipe/examples/ios/objectdetectiongpu:ObjectDetectionGpuApp",
    "//mediapipe/objc:mediapipe_framework_ios"
@@ -84,6 +86,8 @@
    "mediapipe/examples/ios/handdetectiongpu/Base.lproj",
    "mediapipe/examples/ios/handtrackinggpu",
    "mediapipe/examples/ios/handtrackinggpu/Base.lproj",
+    "mediapipe/examples/ios/multihandtrackinggpu",
+    "mediapipe/examples/ios/multihandtrackinggpu/Base.lproj",
    "mediapipe/examples/ios/objectdetectioncpu",
    "mediapipe/examples/ios/objectdetectioncpu/Base.lproj",
    "mediapipe/examples/ios/objectdetectiongpu",
@@ -16,6 +16,7 @@
    "mediapipe/examples/ios/facedetectiongpu",
    "mediapipe/examples/ios/handdetectiongpu",
    "mediapipe/examples/ios/handtrackinggpu",
+    "mediapipe/examples/ios/multihandtrackinggpu",
    "mediapipe/examples/ios/objectdetectioncpu",
    "mediapipe/examples/ios/objectdetectiongpu"
  ],
@@ -67,6 +67,23 @@ mediapipe_cc_proto_library(
    deps = [":spectrogram_calculator_proto"],
 )

+proto_library(
+    name = "stabilized_log_calculator_proto",
+    srcs = ["stabilized_log_calculator.proto"],
+    visibility = ["//visibility:public"],
+    deps = [
+        "//mediapipe/framework:calculator_proto",
+    ],
+)
+
+mediapipe_cc_proto_library(
+    name = "stabilized_log_calculator_cc_proto",
+    srcs = ["stabilized_log_calculator.proto"],
+    cc_deps = ["//mediapipe/framework:calculator_cc_proto"],
+    visibility = ["//visibility:public"],
+    deps = [":stabilized_log_calculator_proto"],
+)
+
 proto_library(
    name = "time_series_framer_calculator_proto",
    srcs = ["time_series_framer_calculator.proto"],
@@ -156,6 +173,22 @@ cc_library(
    alwayslink = 1,
 )

+cc_library(
+    name = "stabilized_log_calculator",
+    srcs = ["stabilized_log_calculator.cc"],
+    visibility = ["//visibility:public"],
+    deps = [
+        ":stabilized_log_calculator_cc_proto",
+        "//mediapipe/framework:calculator_framework",
+        "//mediapipe/framework/formats:matrix",
+        "//mediapipe/framework/formats:time_series_header_cc_proto",
+        "//mediapipe/framework/port:core_proto",
+        "//mediapipe/framework/port:status",
+        "//mediapipe/util:time_series_util",
+    ],
+    alwayslink = 1,
+)
+
 cc_library(
    name = "spectrogram_calculator",
    srcs = ["spectrogram_calculator.cc"],
@@ -266,6 +299,24 @@ cc_test(
    ],
 )

+cc_test(
+    name = "stabilized_log_calculator_test",
+    srcs = ["stabilized_log_calculator_test.cc"],
+    deps = [
+        ":stabilized_log_calculator",
+        ":stabilized_log_calculator_cc_proto",
+        "//mediapipe/framework:calculator_framework",
+        "//mediapipe/framework:calculator_runner",
+        "//mediapipe/framework/formats:matrix",
+        "//mediapipe/framework/formats:time_series_header_cc_proto",
+        "//mediapipe/framework/port:gtest_main",
+        "//mediapipe/framework/port:integral_types",
+        "//mediapipe/framework/port:status",
+        "//mediapipe/util:time_series_test_util",
+        "@eigen_archive//:eigen",
+    ],
+)
+
 cc_test(
    name = "time_series_framer_calculator_test",
    srcs = ["time_series_framer_calculator_test.cc"],
@@ -61,10 +61,12 @@ class AudioDecoderCalculator : public CalculatorBase {
 ::mediapipe::Status AudioDecoderCalculator::GetContract(
    CalculatorContract* cc) {
  cc->InputSidePackets().Tag("INPUT_FILE_PATH").Set<std::string>();
-
+  if (cc->InputSidePackets().HasTag("OPTIONS")) {
+    cc->InputSidePackets().Tag("OPTIONS").Set<mediapipe::AudioDecoderOptions>();
+  }
  cc->Outputs().Tag("AUDIO").Set<Matrix>();
  if (cc->Outputs().HasTag("AUDIO_HEADER")) {
-    cc->Outputs().Tag("AUDIO_HEADER").Set<mediapipe::TimeSeriesHeader>();
+    cc->Outputs().Tag("AUDIO_HEADER").SetNone();
  }
  return ::mediapipe::OkStatus();
 }
@@ -72,9 +74,11 @@ class AudioDecoderCalculator : public CalculatorBase {
 ::mediapipe::Status AudioDecoderCalculator::Open(CalculatorContext* cc) {
  const std::string& input_file_path =
      cc->InputSidePackets().Tag("INPUT_FILE_PATH").Get<std::string>();
-  const auto& decoder_options = cc->Options<mediapipe::AudioDecoderOptions>();
+  const auto& decoder_options =
+      tool::RetrieveOptions(cc->Options<mediapipe::AudioDecoderOptions>(),
+                            cc->InputSidePackets(), "OPTIONS");
  decoder_ = absl::make_unique<AudioDecoder>();
-  RETURN_IF_ERROR(decoder_->Initialize(input_file_path, decoder_options));
+  MP_RETURN_IF_ERROR(decoder_->Initialize(input_file_path, decoder_options));
  std::unique_ptr<mediapipe::TimeSeriesHeader> header =
      absl::make_unique<mediapipe::TimeSeriesHeader>();
  if (decoder_->FillAudioHeader(decoder_options.audio_stream(0), header.get())
@@ -39,11 +39,10 @@ TEST(AudioDecoderCalculatorTest, TestWAV) {
      file::JoinPath("./",
                     "/mediapipe/calculators/audio/"
                     "testdata/sine_wave_1k_44100_mono_2_sec_wav.audio"));
-  MEDIAPIPE_ASSERT_OK(runner.Run());
-  MEDIAPIPE_EXPECT_OK(
-      runner.Outputs()
-          .Tag("AUDIO_HEADER")
-          .header.ValidateAsType<mediapipe::TimeSeriesHeader>());
+  MP_ASSERT_OK(runner.Run());
+  MP_EXPECT_OK(runner.Outputs()
+                   .Tag("AUDIO_HEADER")
+                   .header.ValidateAsType<mediapipe::TimeSeriesHeader>());
  const mediapipe::TimeSeriesHeader& header =
      runner.Outputs()
          .Tag("AUDIO_HEADER")
@@ -71,11 +70,10 @@ TEST(AudioDecoderCalculatorTest, Test48KWAV) {
      file::JoinPath("./",
                     "/mediapipe/calculators/audio/"
                     "testdata/sine_wave_1k_48000_stereo_2_sec_wav.audio"));
-  MEDIAPIPE_ASSERT_OK(runner.Run());
-  MEDIAPIPE_EXPECT_OK(
-      runner.Outputs()
-          .Tag("AUDIO_HEADER")
-          .header.ValidateAsType<mediapipe::TimeSeriesHeader>());
+  MP_ASSERT_OK(runner.Run());
+  MP_EXPECT_OK(runner.Outputs()
+                   .Tag("AUDIO_HEADER")
+                   .header.ValidateAsType<mediapipe::TimeSeriesHeader>());
  const mediapipe::TimeSeriesHeader& header =
      runner.Outputs()
          .Tag("AUDIO_HEADER")
@@ -103,11 +101,10 @@ TEST(AudioDecoderCalculatorTest, TestMP3) {
      file::JoinPath("./",
                     "/mediapipe/calculators/audio/"
                     "testdata/sine_wave_1k_44100_stereo_2_sec_mp3.audio"));
-  MEDIAPIPE_ASSERT_OK(runner.Run());
-  MEDIAPIPE_EXPECT_OK(
-      runner.Outputs()
-          .Tag("AUDIO_HEADER")
-          .header.ValidateAsType<mediapipe::TimeSeriesHeader>());
+  MP_ASSERT_OK(runner.Run());
+  MP_EXPECT_OK(runner.Outputs()
+                   .Tag("AUDIO_HEADER")
+                   .header.ValidateAsType<mediapipe::TimeSeriesHeader>());
  const mediapipe::TimeSeriesHeader& header =
      runner.Outputs()
          .Tag("AUDIO_HEADER")
@@ -135,11 +132,10 @@ TEST(AudioDecoderCalculatorTest, TestAAC) {
      file::JoinPath("./",
                     "/mediapipe/calculators/audio/"
                     "testdata/sine_wave_1k_44100_stereo_2_sec_aac.audio"));
-  MEDIAPIPE_ASSERT_OK(runner.Run());
-  MEDIAPIPE_EXPECT_OK(
-      runner.Outputs()
-          .Tag("AUDIO_HEADER")
-          .header.ValidateAsType<mediapipe::TimeSeriesHeader>());
+  MP_ASSERT_OK(runner.Run());
+  MP_EXPECT_OK(runner.Outputs()
+                   .Tag("AUDIO_HEADER")
+                   .header.ValidateAsType<mediapipe::TimeSeriesHeader>());
  const mediapipe::TimeSeriesHeader& header =
      runner.Outputs()
          .Tag("AUDIO_HEADER")
@@ -51,11 +51,11 @@ static bool SafeMultiply(int x, int y, int* result) {

 ::mediapipe::Status BasicTimeSeriesCalculatorBase::Open(CalculatorContext* cc) {
  TimeSeriesHeader input_header;
-  RETURN_IF_ERROR(time_series_util::FillTimeSeriesHeaderIfValid(
+  MP_RETURN_IF_ERROR(time_series_util::FillTimeSeriesHeaderIfValid(
      cc->Inputs().Index(0).Header(), &input_header));

  auto output_header = new TimeSeriesHeader(input_header);
-  RETURN_IF_ERROR(MutateHeader(output_header));
+  MP_RETURN_IF_ERROR(MutateHeader(output_header));
  cc->Outputs().Index(0).SetHeader(Adopt(output_header));
  return ::mediapipe::OkStatus();
 }
@@ -63,11 +63,11 @@ static bool SafeMultiply(int x, int y, int* result) {
 ::mediapipe::Status BasicTimeSeriesCalculatorBase::Process(
    CalculatorContext* cc) {
  const Matrix& input = cc->Inputs().Index(0).Get<Matrix>();
-  RETURN_IF_ERROR(time_series_util::IsMatrixShapeConsistentWithHeader(
+  MP_RETURN_IF_ERROR(time_series_util::IsMatrixShapeConsistentWithHeader(
      input, cc->Inputs().Index(0).Header().Get<TimeSeriesHeader>()));

  std::unique_ptr<Matrix> output(new Matrix(ProcessMatrix(input)));
-  RETURN_IF_ERROR(time_series_util::IsMatrixShapeConsistentWithHeader(
+  MP_RETURN_IF_ERROR(time_series_util::IsMatrixShapeConsistentWithHeader(
      *output, cc->Outputs().Index(0).Header().Get<TimeSeriesHeader>()));

  cc->Outputs().Index(0).Add(output.release(), cc->InputTimestamp());
@@ -90,8 +90,8 @@ class FramewiseTransformCalculatorBase : public CalculatorBase {
 private:
  // Takes header and options, and sets up state including calling
  // set_num_output_channels() on the base object.
-  virtual ::mediapipe::Status ConfigureTransform(
-      const TimeSeriesHeader& header, const CalculatorOptions& options) = 0;
+  virtual ::mediapipe::Status ConfigureTransform(const TimeSeriesHeader& header,
+                                                 CalculatorContext* cc) = 0;

  // Takes a vector<double> corresponding to an input frame, and
  // perform the specific transformation to produce an output frame.
@@ -105,10 +105,10 @@ class FramewiseTransformCalculatorBase : public CalculatorBase {
 ::mediapipe::Status FramewiseTransformCalculatorBase::Open(
    CalculatorContext* cc) {
  TimeSeriesHeader input_header;
-  RETURN_IF_ERROR(time_series_util::FillTimeSeriesHeaderIfValid(
+  MP_RETURN_IF_ERROR(time_series_util::FillTimeSeriesHeaderIfValid(
      cc->Inputs().Index(0).Header(), &input_header));

-  ::mediapipe::Status status = ConfigureTransform(input_header, cc->Options());
+  ::mediapipe::Status status = ConfigureTransform(input_header, cc);

  auto output_header = new TimeSeriesHeader(input_header);
  output_header->set_num_channels(num_output_channels_);
@@ -175,11 +175,9 @@ class MfccCalculator : public FramewiseTransformCalculatorBase {
  }

 private:
-  ::mediapipe::Status ConfigureTransform(
-      const TimeSeriesHeader& header,
-      const CalculatorOptions& options) override {
-    MfccCalculatorOptions mfcc_options;
-    time_series_util::FillOptionsExtensionOrDie(options, &mfcc_options);
+  ::mediapipe::Status ConfigureTransform(const TimeSeriesHeader& header,
+                                         CalculatorContext* cc) override {
+    MfccCalculatorOptions mfcc_options = cc->Options<MfccCalculatorOptions>();
    mfcc_.reset(new audio_dsp::Mfcc());
    int input_length = header.num_channels();
    // Set up the parameters to the Mfcc object.
@@ -235,11 +233,10 @@ class MelSpectrumCalculator : public FramewiseTransformCalculatorBase {
  }

 private:
-  ::mediapipe::Status ConfigureTransform(
-      const TimeSeriesHeader& header,
-      const CalculatorOptions& options) override {
-    MelSpectrumCalculatorOptions mel_spectrum_options;
-    time_series_util::FillOptionsExtensionOrDie(options, &mel_spectrum_options);
+  ::mediapipe::Status ConfigureTransform(const TimeSeriesHeader& header,
+                                         CalculatorContext* cc) override {
+    MelSpectrumCalculatorOptions mel_spectrum_options =
+        cc->Options<MelSpectrumCalculatorOptions>();
    mel_filterbank_.reset(new audio_dsp::MelFilterbank());
    int input_length = header.num_channels();
    set_num_output_channels(mel_spectrum_options.channel_count());
@@ -112,7 +112,7 @@ TEST_F(MfccCalculatorTest, AudioSampleRateFromInputHeader) {
  SetupGraphAndHeader();
  SetupRandomInputPackets();

-  MEDIAPIPE_EXPECT_OK(Run());
+  MP_EXPECT_OK(Run());

  CheckResults(options_.mfcc_count());
 }
@@ -134,7 +134,7 @@ TEST_F(MelSpectrumCalculatorTest, AudioSampleRateFromInputHeader) {
  SetupGraphAndHeader();
  SetupRandomInputPackets();

-  MEDIAPIPE_EXPECT_OK(Run());
+  MP_EXPECT_OK(Run());

  CheckResults(options_.channel_count());
 }
@@ -64,8 +64,8 @@ void CopyVectorToChannel(const std::vector<float>& vec, Matrix* matrix,

 ::mediapipe::Status RationalFactorResampleCalculator::Open(
    CalculatorContext* cc) {
-  RationalFactorResampleCalculatorOptions resample_options;
-  time_series_util::FillOptionsExtensionOrDie(cc->Options(), &resample_options);
+  RationalFactorResampleCalculatorOptions resample_options =
+      cc->Options<RationalFactorResampleCalculatorOptions>();

  if (!resample_options.has_target_sample_rate()) {
    return tool::StatusInvalid(
@@ -74,7 +74,7 @@ void CopyVectorToChannel(const std::vector<float>& vec, Matrix* matrix,
  target_sample_rate_ = resample_options.target_sample_rate();

  TimeSeriesHeader input_header;
-  RETURN_IF_ERROR(time_series_util::FillTimeSeriesHeaderIfValid(
+  MP_RETURN_IF_ERROR(time_series_util::FillTimeSeriesHeaderIfValid(
      cc->Inputs().Index(0).Header(), &input_header));

  source_sample_rate_ = input_header.sample_rate();
@@ -209,25 +209,25 @@ class RationalFactorResampleCalculatorTest

 TEST_F(RationalFactorResampleCalculatorTest, Upsample) {
  const double kUpsampleRate = input_sample_rate_ * 1.9;
-  MEDIAPIPE_ASSERT_OK(Run(kUpsampleRate));
+  MP_ASSERT_OK(Run(kUpsampleRate));
  CheckOutput(kUpsampleRate);
 }

 TEST_F(RationalFactorResampleCalculatorTest, Downsample) {
  const double kDownsampleRate = input_sample_rate_ / 1.9;
-  MEDIAPIPE_ASSERT_OK(Run(kDownsampleRate));
+  MP_ASSERT_OK(Run(kDownsampleRate));
  CheckOutput(kDownsampleRate);
 }

 TEST_F(RationalFactorResampleCalculatorTest, UsesRationalFactorResampler) {
  const double kUpsampleRate = input_sample_rate_ * 2;
-  MEDIAPIPE_ASSERT_OK(Run(kUpsampleRate));
+  MP_ASSERT_OK(Run(kUpsampleRate));
  CheckOutput(kUpsampleRate);
 }

 TEST_F(RationalFactorResampleCalculatorTest, PassthroughIfSampleRateUnchanged) {
  const double kUpsampleRate = input_sample_rate_;
-  MEDIAPIPE_ASSERT_OK(Run(kUpsampleRate));
+  MP_ASSERT_OK(Run(kUpsampleRate));
  CheckOutputUnchanged();
 }

@@ -239,7 +239,7 @@ TEST_F(RationalFactorResampleCalculatorTest, DoesNotDieOnEmptyInput) {
  options_.set_target_sample_rate(input_sample_rate_);
  InitializeGraph();
  FillInputHeader();
-  MEDIAPIPE_ASSERT_OK(RunGraph());
+  MP_ASSERT_OK(RunGraph());
  EXPECT_TRUE(output().packets.empty());
 }

@@ -71,10 +71,8 @@ class SpectrogramCalculator : public CalculatorBase {
        // Input stream with TimeSeriesHeader.
    );

-    SpectrogramCalculatorOptions spectrogram_options;
-    time_series_util::FillOptionsExtensionOrDie(cc->Options(),
-                                                &spectrogram_options);
-
+    SpectrogramCalculatorOptions spectrogram_options =
+        cc->Options<SpectrogramCalculatorOptions>();
    if (!spectrogram_options.allow_multichannel_input()) {
      if (spectrogram_options.output_type() ==
          SpectrogramCalculatorOptions::COMPLEX) {
@@ -115,8 +113,15 @@ class SpectrogramCalculator : public CalculatorBase {
  ::mediapipe::Status Close(CalculatorContext* cc) override;

 private:
-  Timestamp CurrentOutputTimestamp() {
-    // Current output timestamp is the *center* of the next frame to be
+  Timestamp CurrentOutputTimestamp(CalculatorContext* cc) {
+    if (use_local_timestamp_) {
+      return cc->InputTimestamp();
+    }
+    return CumulativeOutputTimestamp();
+  }
+
+  Timestamp CumulativeOutputTimestamp() {
+    // Cumulative output timestamp is the *center* of the next frame to be
    // emitted, hence delayed by half a window duration compared to relevant
    // input timestamp.
    return initial_input_timestamp_ +
@@ -143,6 +148,7 @@ class SpectrogramCalculator : public CalculatorBase {
      const OutputMatrixType postprocess_output_fn(const OutputMatrixType&),
      CalculatorContext* cc);

+  bool use_local_timestamp_;
  double input_sample_rate_;
  bool pad_final_packet_;
  int frame_duration_samples_;
@@ -172,9 +178,10 @@ REGISTER_CALCULATOR(SpectrogramCalculator);
 const float SpectrogramCalculator::kLnPowerToDb = 4.342944819032518;

 ::mediapipe::Status SpectrogramCalculator::Open(CalculatorContext* cc) {
-  SpectrogramCalculatorOptions spectrogram_options;
-  time_series_util::FillOptionsExtensionOrDie(cc->Options(),
-                                              &spectrogram_options);
+  SpectrogramCalculatorOptions spectrogram_options =
+      cc->Options<SpectrogramCalculatorOptions>();
+
+  use_local_timestamp_ = spectrogram_options.use_local_timestamp();

  if (spectrogram_options.frame_duration_seconds() <= 0.0) {
    ::mediapipe::InvalidArgumentErrorBuilder(MEDIAPIPE_LOC)
@@ -197,7 +204,7 @@ const float SpectrogramCalculator::kLnPowerToDb = 4.342944819032518;
  }

  TimeSeriesHeader input_header;
-  RETURN_IF_ERROR(time_series_util::FillTimeSeriesHeaderIfValid(
+  MP_RETURN_IF_ERROR(time_series_util::FillTimeSeriesHeaderIfValid(
      cc->Inputs().Index(0).Header(), &input_header));

  input_sample_rate_ = input_header.sample_rate();
@@ -223,6 +230,10 @@ const float SpectrogramCalculator::kLnPowerToDb = 4.342944819032518;

  std::vector<double> window;
  switch (spectrogram_options.window_type()) {
+    case SpectrogramCalculatorOptions::COSINE:
+      audio_dsp::CosineWindow().GetPeriodicSamples(frame_duration_samples_,
+                                                   &window);
+      break;
    case SpectrogramCalculatorOptions::HANN:
      audio_dsp::HannWindow().GetPeriodicSamples(frame_duration_samples_,
                                                 &window);
@@ -350,11 +361,11 @@ template <class OutputMatrixType>
        << "Inconsistent number of spectrogram channels.";
    if (allow_multichannel_input_) {
      cc->Outputs().Index(0).Add(spectrogram_matrices.release(),
-                                 CurrentOutputTimestamp());
+                                 CurrentOutputTimestamp(cc));
    } else {
      cc->Outputs().Index(0).Add(
          new OutputMatrixType(spectrogram_matrices->at(0)),
-          CurrentOutputTimestamp());
+          CurrentOutputTimestamp(cc));
    }
    cumulative_completed_frames_ += output_vectors.size();
  }
@@ -58,6 +58,7 @@ message SpectrogramCalculatorOptions {
  enum WindowType {
    HANN = 0;
    HAMMING = 1;
+    COSINE = 2;
  }
  optional WindowType window_type = 6 [default = HANN];

@@ -65,4 +66,11 @@ message SpectrogramCalculatorOptions {
  // uniformly regardless of output type (i.e., even dBs are multiplied, not
  // offset).
  optional double output_scale = 7 [default = 1.0];
+
+  // If use_local_timestamp is true, the output packet's timestamp is based on
+  // the last sample of the packet and it's inferred from the latest input
+  // packet's timestamp.  If false, the output packet's timestamp is based on
+  // the cumulative timestamping, which is inferred from the intial input
+  // timestamp and the cumulative number of samples.
+  optional bool use_local_timestamp = 8 [default = false];
 }
@@ -303,7 +303,7 @@ TEST_F(SpectrogramCalculatorTest, IntegerFrameDurationNoOverlap) {
  FillInputHeader();
  SetupConstantInputPackets(input_packet_sizes);

-  MEDIAPIPE_ASSERT_OK(Run());
+  MP_ASSERT_OK(Run());

  CheckOutputHeadersAndTimestamps();
  EXPECT_EQ(OutputFramesPerPacket(), expected_output_packet_sizes);
@@ -324,7 +324,7 @@ TEST_F(SpectrogramCalculatorTest, IntegerFrameDurationSomeOverlap) {
  FillInputHeader();
  SetupConstantInputPackets(input_packet_sizes);

-  MEDIAPIPE_ASSERT_OK(Run());
+  MP_ASSERT_OK(Run());

  CheckOutputHeadersAndTimestamps();
  EXPECT_EQ(OutputFramesPerPacket(), expected_output_packet_sizes);
@@ -344,7 +344,7 @@ TEST_F(SpectrogramCalculatorTest, NonintegerFrameDurationAndOverlap) {
  FillInputHeader();
  SetupConstantInputPackets(input_packet_sizes);

-  MEDIAPIPE_ASSERT_OK(Run());
+  MP_ASSERT_OK(Run());

  CheckOutputHeadersAndTimestamps();
  EXPECT_EQ(OutputFramesPerPacket(), expected_output_packet_sizes);
@@ -365,7 +365,7 @@ TEST_F(SpectrogramCalculatorTest, ShortInitialPacketNoOverlap) {
  FillInputHeader();
  SetupConstantInputPackets(input_packet_sizes);

-  MEDIAPIPE_ASSERT_OK(Run());
+  MP_ASSERT_OK(Run());

  CheckOutputHeadersAndTimestamps();
  EXPECT_EQ(OutputFramesPerPacket(), expected_output_packet_sizes);
@@ -382,7 +382,7 @@ TEST_F(SpectrogramCalculatorTest, TrailingSamplesNoPad) {
  FillInputHeader();
  SetupConstantInputPackets(input_packet_sizes);

-  MEDIAPIPE_ASSERT_OK(Run());
+  MP_ASSERT_OK(Run());

  CheckOutputHeadersAndTimestamps();
  EXPECT_EQ(OutputFramesPerPacket(), expected_output_packet_sizes);
@@ -399,7 +399,7 @@ TEST_F(SpectrogramCalculatorTest, NoTrailingSamplesWithPad) {
  FillInputHeader();
  SetupConstantInputPackets(input_packet_sizes);

-  MEDIAPIPE_ASSERT_OK(Run());
+  MP_ASSERT_OK(Run());

  CheckOutputHeadersAndTimestamps();
  EXPECT_EQ(OutputFramesPerPacket(), expected_output_packet_sizes);
@@ -418,7 +418,7 @@ TEST_F(SpectrogramCalculatorTest, TrailingSamplesWithPad) {
  FillInputHeader();
  SetupConstantInputPackets(input_packet_sizes);

-  MEDIAPIPE_ASSERT_OK(Run());
+  MP_ASSERT_OK(Run());

  CheckOutputHeadersAndTimestamps();
  EXPECT_EQ(OutputFramesPerPacket(), expected_output_packet_sizes);
@@ -435,7 +435,7 @@ TEST_F(SpectrogramCalculatorTest, VeryShortInputWillPad) {
  FillInputHeader();
  SetupConstantInputPackets(input_packet_sizes);

-  MEDIAPIPE_ASSERT_OK(Run());
+  MP_ASSERT_OK(Run());

  CheckOutputHeadersAndTimestamps();
  EXPECT_EQ(OutputFramesPerPacket(), expected_output_packet_sizes);
@@ -452,7 +452,7 @@ TEST_F(SpectrogramCalculatorTest, VeryShortInputZeroOutputFramesIfNoPad) {
  FillInputHeader();
  SetupConstantInputPackets(input_packet_sizes);

-  MEDIAPIPE_ASSERT_OK(Run());
+  MP_ASSERT_OK(Run());

  CheckOutputHeadersAndTimestamps();
  EXPECT_EQ(OutputFramesPerPacket(), expected_output_packet_sizes);
@@ -468,7 +468,7 @@ TEST_F(SpectrogramCalculatorTest, DCSignalIsPeakBin) {
  // Setup packets with DC input (non-zero constant value).
  SetupConstantInputPackets(input_packet_sizes);

-  MEDIAPIPE_ASSERT_OK(Run());
+  MP_ASSERT_OK(Run());

  CheckOutputHeadersAndTimestamps();
  const float dc_frequency_hz = 0.0;
@@ -486,7 +486,7 @@ TEST_F(SpectrogramCalculatorTest, A440ToneIsPeakBin) {
  const float tone_frequency_hz = 440.0;
  SetupCosineInputPackets(input_packet_sizes, tone_frequency_hz);

-  MEDIAPIPE_ASSERT_OK(Run());
+  MP_ASSERT_OK(Run());

  CheckOutputHeadersAndTimestamps();
  int num_output_frames = output().packets[0].Get<Matrix>().cols();
@@ -507,7 +507,7 @@ TEST_F(SpectrogramCalculatorTest, SquaredMagnitudeOutputLooksRight) {
  // Setup packets with DC input (non-zero constant value).
  SetupConstantInputPackets(input_packet_sizes);

-  MEDIAPIPE_ASSERT_OK(Run());
+  MP_ASSERT_OK(Run());

  CheckOutputHeadersAndTimestamps();
  EXPECT_FLOAT_EQ(output().packets[0].Get<Matrix>()(0, 0),
@@ -525,7 +525,7 @@ TEST_F(SpectrogramCalculatorTest, DefaultOutputIsSquaredMagnitude) {
  // Setup packets with DC input (non-zero constant value).
  SetupConstantInputPackets(input_packet_sizes);

-  MEDIAPIPE_ASSERT_OK(Run());
+  MP_ASSERT_OK(Run());

  CheckOutputHeadersAndTimestamps();
  EXPECT_FLOAT_EQ(output().packets[0].Get<Matrix>()(0, 0),
@@ -543,7 +543,7 @@ TEST_F(SpectrogramCalculatorTest, LinearMagnitudeOutputLooksRight) {
  // Setup packets with DC input (non-zero constant value).
  SetupConstantInputPackets(input_packet_sizes);

-  MEDIAPIPE_ASSERT_OK(Run());
+  MP_ASSERT_OK(Run());

  CheckOutputHeadersAndTimestamps();
  EXPECT_FLOAT_EQ(output().packets[0].Get<Matrix>()(0, 0),
@@ -561,7 +561,7 @@ TEST_F(SpectrogramCalculatorTest, DbMagnitudeOutputLooksRight) {
  // Setup packets with DC input (non-zero constant value).
  SetupConstantInputPackets(input_packet_sizes);

-  MEDIAPIPE_ASSERT_OK(Run());
+  MP_ASSERT_OK(Run());

  CheckOutputHeadersAndTimestamps();
  EXPECT_FLOAT_EQ(output().packets[0].Get<Matrix>()(0, 0),
@@ -581,7 +581,7 @@ TEST_F(SpectrogramCalculatorTest, OutputScalingLooksRight) {
  // Setup packets with DC input (non-zero constant value).
  SetupConstantInputPackets(input_packet_sizes);

-  MEDIAPIPE_ASSERT_OK(Run());
+  MP_ASSERT_OK(Run());

  CheckOutputHeadersAndTimestamps();
  EXPECT_FLOAT_EQ(
@@ -600,7 +600,7 @@ TEST_F(SpectrogramCalculatorTest, ComplexOutputLooksRight) {
  // Setup packets with DC input (non-zero constant value).
  SetupConstantInputPackets(input_packet_sizes);

-  MEDIAPIPE_ASSERT_OK(Run());
+  MP_ASSERT_OK(Run());

  CheckOutputHeadersAndTimestamps();
  EXPECT_FLOAT_EQ(std::norm(output().packets[0].Get<Eigen::MatrixXcf>()(0, 0)),
@@ -623,7 +623,7 @@ TEST_F(SpectrogramCalculatorTest, ComplexOutputLooksRightForImpulses) {
  // Make two impulse packets offset one sample from each other
  SetupImpulseInputPackets(input_packet_sizes, input_packet_impulse_offsets);

-  MEDIAPIPE_ASSERT_OK(Run());
+  MP_ASSERT_OK(Run());

  CheckOutputHeadersAndTimestamps();
  const int num_buckets =
@@ -671,7 +671,7 @@ TEST_F(SpectrogramCalculatorTest, SquaredMagnitudeOutputLooksRightForNonDC) {
  const float tone_frequency_hz = target_bin * (input_sample_rate_ / fft_size);
  SetupCosineInputPackets(input_packet_sizes, tone_frequency_hz);

-  MEDIAPIPE_ASSERT_OK(Run());
+  MP_ASSERT_OK(Run());

  CheckOutputHeadersAndTimestamps();
  // For a non-DC bin, the magnitude will be split between positive and
@@ -696,7 +696,7 @@ TEST_F(SpectrogramCalculatorTest, ZeroOutputsForZeroInputsWithPaddingEnabled) {
  FillInputHeader();
  SetupConstantInputPackets(input_packet_sizes);

-  MEDIAPIPE_ASSERT_OK(Run());
+  MP_ASSERT_OK(Run());

  CheckOutputHeadersAndTimestamps();
  EXPECT_EQ(OutputFramesPerPacket(), expected_output_packet_sizes);
@@ -713,7 +713,7 @@ TEST_F(SpectrogramCalculatorTest, NumChannelsIsRight) {
  FillInputHeader();
  const float tone_frequency_hz = 440.0;
  SetupCosineInputPackets(input_packet_sizes, tone_frequency_hz);
-  MEDIAPIPE_ASSERT_OK(Run());
+  MP_ASSERT_OK(Run());

  CheckOutputHeadersAndTimestamps();
  EXPECT_EQ(output().packets[0].Get<std::vector<Matrix>>().size(),
@@ -732,7 +732,7 @@ TEST_F(SpectrogramCalculatorTest, NumSamplesAndPacketRateAreCleared) {
  FillInputHeader();
  SetupConstantInputPackets(input_packet_sizes);

-  MEDIAPIPE_ASSERT_OK(Run());
+  MP_ASSERT_OK(Run());

  const TimeSeriesHeader& output_header =
      output().header.Get<TimeSeriesHeader>();
@@ -751,7 +751,7 @@ TEST_F(SpectrogramCalculatorTest, MultichannelSpectrogramSizesAreRight) {
  FillInputHeader();
  const float tone_frequency_hz = 440.0;
  SetupCosineInputPackets(input_packet_sizes, tone_frequency_hz);
-  MEDIAPIPE_ASSERT_OK(Run());
+  MP_ASSERT_OK(Run());

  CheckOutputHeadersAndTimestamps();
  auto spectrograms = output().packets[0].Get<std::vector<Matrix>>();
@@ -776,7 +776,7 @@ TEST_F(SpectrogramCalculatorTest, MultichannelSpectrogramValuesAreRight) {
  const float tone_frequency_hz = 440.0;
  SetupMultichannelInputPackets(input_packet_sizes, tone_frequency_hz);

-  MEDIAPIPE_ASSERT_OK(Run());
+  MP_ASSERT_OK(Run());

  CheckOutputHeadersAndTimestamps();
  auto spectrograms = output().packets[0].Get<std::vector<Matrix>>();
@@ -805,7 +805,7 @@ TEST_F(SpectrogramCalculatorTest, MultichannelHandlesShortInitialPacket) {
  FillInputHeader();
  const float tone_frequency_hz = 440.0;
  SetupCosineInputPackets(input_packet_sizes, tone_frequency_hz);
-  MEDIAPIPE_ASSERT_OK(Run());
+  MP_ASSERT_OK(Run());

  CheckOutputHeadersAndTimestamps();
  auto spectrograms = output().packets[0].Get<std::vector<Matrix>>();
@@ -833,7 +833,7 @@ TEST_F(SpectrogramCalculatorTest,
  FillInputHeader();
  const float tone_frequency_hz = 440.0;
  SetupCosineInputPackets(input_packet_sizes, tone_frequency_hz);
-  MEDIAPIPE_ASSERT_OK(Run());
+  MP_ASSERT_OK(Run());

  CheckOutputHeadersAndTimestamps();
  auto spectrograms = output().packets[0].Get<std::vector<Eigen::MatrixXcf>>();
@@ -0,0 +1,99 @@
+// Copyright 2019 The MediaPipe Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+// Defines StabilizedLogCalculator.
+
+#include <cmath>
+#include <memory>
+#include <string>
+
+#include "mediapipe/calculators/audio/stabilized_log_calculator.pb.h"
+#include "mediapipe/framework/calculator_framework.h"
+#include "mediapipe/framework/formats/matrix.h"
+#include "mediapipe/framework/formats/time_series_header.pb.h"
+#include "mediapipe/framework/port/proto_ns.h"
+#include "mediapipe/util/time_series_util.h"
+
+namespace mediapipe {
+
+// Example config:
+// node {
+//   calculator: "StabilizedLogCalculator"
+//   input_stream: "input_time_series"
+//   output_stream: "stabilized_log_time_series"
+//   options {
+//     [mediapipe.StabilizedLogCalculatorOptions.ext] {
+//       stabilizer: .00001
+//       check_nonnegativity: true
+//     }
+//   }
+// }
+class StabilizedLogCalculator : public CalculatorBase {
+ public:
+  static ::mediapipe::Status GetContract(CalculatorContract* cc) {
+    cc->Inputs().Index(0).Set<Matrix>(
+        // Input stream with TimeSeriesHeader.
+    );
+    cc->Outputs().Index(0).Set<Matrix>(
+        // Output stabilized log stream with TimeSeriesHeader.
+    );
+    return ::mediapipe::OkStatus();
+  }
+
+  ::mediapipe::Status Open(CalculatorContext* cc) override {
+    StabilizedLogCalculatorOptions stabilized_log_calculator_options =
+        cc->Options<StabilizedLogCalculatorOptions>();
+
+    stabilizer_ = stabilized_log_calculator_options.stabilizer();
+    output_scale_ = stabilized_log_calculator_options.output_scale();
+    check_nonnegativity_ =
+        stabilized_log_calculator_options.check_nonnegativity();
+    CHECK_GE(stabilizer_, 0.0)
+        << "stabilizer must be >= 0.0, received a value of " << stabilizer_;
+
+    // If the input packets have a header, propagate the header to the output.
+    if (!cc->Inputs().Index(0).Header().IsEmpty()) {
+      TimeSeriesHeader input_header;
+      MP_RETURN_IF_ERROR(time_series_util::FillTimeSeriesHeaderIfValid(
+          cc->Inputs().Index(0).Header(), &input_header));
+      cc->Outputs().Index(0).SetHeader(
+          Adopt(new TimeSeriesHeader(input_header)));
+    }
+    return ::mediapipe::OkStatus();
+  }
+
+  ::mediapipe::Status Process(CalculatorContext* cc) override {
+    auto input_matrix = cc->Inputs().Index(0).Get<Matrix>();
+    if (input_matrix.array().isNaN().any()) {
+      return ::mediapipe::InvalidArgumentError("NaN input to log operation.");
+    }
+    if (check_nonnegativity_) {
+      if (input_matrix.minCoeff() < 0.0) {
+        return ::mediapipe::OutOfRangeError("Negative input to log operation.");
+      }
+    }
+    std::unique_ptr<Matrix> output_frame(new Matrix(
+        output_scale_ * (input_matrix.array() + stabilizer_).log().matrix()));
+    cc->Outputs().Index(0).Add(output_frame.release(), cc->InputTimestamp());
+    return ::mediapipe::OkStatus();
+  }
+
+ private:
+  float stabilizer_;
+  bool check_nonnegativity_;
+  double output_scale_;
+};
+REGISTER_CALCULATOR(StabilizedLogCalculator);
+
+}  // namespace mediapipe
@@ -0,0 +1,37 @@
+// Copyright 2019 The MediaPipe Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+syntax = "proto2";
+
+package mediapipe;
+
+import "mediapipe/framework/calculator.proto";
+
+message StabilizedLogCalculatorOptions {
+  extend CalculatorOptions {
+    optional StabilizedLogCalculatorOptions ext = 101978339;
+  }
+
+  // The calculator computes log(x + stabilizer). stabilizer must be >=
+  // 0, with 0 indicating a lack of stabilization.
+  optional float stabilizer = 1 [default = .00001];
+
+  // If true, CHECK that all input values in are >= 0. If false, the
+  // code will take the log of the potentially negative input values
+  // plus the stabilizer.
+  optional bool check_nonnegativity = 2 [default = true];
+
+  // Support a fixed multiplicative scaling of the output.
+  optional double output_scale = 3 [default = 1.0];
+}
@@ -0,0 +1,141 @@
+// Copyright 2019 The MediaPipe Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+#include <cmath>
+
+#include "Eigen/Core"
+#include "mediapipe/calculators/audio/stabilized_log_calculator.pb.h"
+#include "mediapipe/framework/calculator_framework.h"
+#include "mediapipe/framework/calculator_runner.h"
+#include "mediapipe/framework/formats/matrix.h"
+#include "mediapipe/framework/formats/time_series_header.pb.h"
+#include "mediapipe/framework/port/gmock.h"
+#include "mediapipe/framework/port/gtest.h"
+#include "mediapipe/framework/port/integral_types.h"
+#include "mediapipe/framework/port/status_matchers.h"
+#include "mediapipe/util/time_series_test_util.h"
+
+namespace mediapipe {
+
+const float kStabilizer = 0.1;
+const int kNumChannels = 3;
+const int kNumSamples = 10;
+
+class StabilizedLogCalculatorTest
+    : public TimeSeriesCalculatorTest<StabilizedLogCalculatorOptions> {
+ protected:
+  void SetUp() override {
+    calculator_name_ = "StabilizedLogCalculator";
+    options_.set_stabilizer(kStabilizer);
+
+    input_sample_rate_ = 8000.0;
+    num_input_channels_ = kNumChannels;
+    num_input_samples_ = kNumSamples;
+  }
+
+  void RunGraphNoReturn() { MP_ASSERT_OK(RunGraph()); }
+};
+
+TEST_F(StabilizedLogCalculatorTest, BasicOperation) {
+  const int kNumPackets = 5;
+
+  InitializeGraph();
+  FillInputHeader();
+
+  std::vector<Matrix> input_data_matrices;
+  for (int input_packet = 0; input_packet < kNumPackets; ++input_packet) {
+    const int64 timestamp = input_packet * Timestamp::kTimestampUnitsPerSecond;
+    Matrix input_data_matrix =
+        Matrix::Random(kNumChannels, kNumSamples).array().abs();
+    input_data_matrices.push_back(input_data_matrix);
+    AppendInputPacket(new Matrix(input_data_matrix), timestamp);
+  }
+
+  MP_ASSERT_OK(RunGraph());
+  ExpectOutputHeaderEqualsInputHeader();
+  for (int output_packet = 0; output_packet < kNumPackets; ++output_packet) {
+    ExpectApproximatelyEqual(
+        (input_data_matrices[output_packet].array() + kStabilizer).log(),
+        runner_->Outputs().Index(0).packets[output_packet].Get<Matrix>());
+  }
+}
+
+TEST_F(StabilizedLogCalculatorTest, OutputScaleWorks) {
+  const int kNumPackets = 5;
+  double output_scale = 2.5;
+  options_.set_output_scale(output_scale);
+
+  InitializeGraph();
+  FillInputHeader();
+
+  std::vector<Matrix> input_data_matrices;
+  for (int input_packet = 0; input_packet < kNumPackets; ++input_packet) {
+    const int64 timestamp = input_packet * Timestamp::kTimestampUnitsPerSecond;
+    Matrix input_data_matrix =
+        Matrix::Random(kNumChannels, kNumSamples).array().abs();
+    input_data_matrices.push_back(input_data_matrix);
+    AppendInputPacket(new Matrix(input_data_matrix), timestamp);
+  }
+
+  MP_ASSERT_OK(RunGraph());
+  ExpectOutputHeaderEqualsInputHeader();
+  for (int output_packet = 0; output_packet < kNumPackets; ++output_packet) {
+    ExpectApproximatelyEqual(
+        output_scale *
+            ((input_data_matrices[output_packet].array() + kStabilizer).log()),
+        runner_->Outputs().Index(0).packets[output_packet].Get<Matrix>());
+  }
+}
+
+TEST_F(StabilizedLogCalculatorTest, ZerosAreStabilized) {
+  InitializeGraph();
+  FillInputHeader();
+  AppendInputPacket(new Matrix(Matrix::Zero(kNumChannels, kNumSamples)),
+                    0 /* timestamp */);
+  MP_ASSERT_OK(RunGraph());
+  ExpectOutputHeaderEqualsInputHeader();
+  ExpectApproximatelyEqual(
+      Matrix::Constant(kNumChannels, kNumSamples, kStabilizer).array().log(),
+      runner_->Outputs().Index(0).packets[0].Get<Matrix>());
+}
+
+TEST_F(StabilizedLogCalculatorTest, NanValuesReturnError) {
+  InitializeGraph();
+  FillInputHeader();
+  AppendInputPacket(
+      new Matrix(Matrix::Constant(kNumChannels, kNumSamples, std::nanf(""))),
+      0 /* timestamp */);
+  ASSERT_FALSE(RunGraph().ok());
+}
+
+TEST_F(StabilizedLogCalculatorTest, NegativeValuesReturnError) {
+  InitializeGraph();
+  FillInputHeader();
+  AppendInputPacket(
+      new Matrix(Matrix::Constant(kNumChannels, kNumSamples, -1.0)),
+      0 /* timestamp */);
+  ASSERT_FALSE(RunGraph().ok());
+}
+
+TEST_F(StabilizedLogCalculatorTest, NegativeValuesDoNotCheckFailIfCheckIsOff) {
+  options_.set_check_nonnegativity(false);
+  InitializeGraph();
+  FillInputHeader();
+  AppendInputPacket(
+      new Matrix(Matrix::Constant(kNumChannels, kNumSamples, -1.0)),
+      0 /* timestamp */);
+  MP_ASSERT_OK(RunGraph());
+  // Results are undefined.
+}
+
+}  // namespace mediapipe
@@ -56,6 +56,14 @@ namespace mediapipe {
 // If pad_final_packet is true, all input samples will be emitted and the final
 // packet will be zero padded as necessary.  If pad_final_packet is false, some
 // samples may be dropped at the end of the stream.
+//
+// If use_local_timestamp is true, the output packet's timestamp is based on the
+// last sample of the packet. The timestamp of this sample is inferred by
+// input_packet_timesamp + local_sample_index / sampling_rate_. If false, the
+// output packet's timestamp is based on the cumulative timestamping, which is
+// done by adopting the timestamp of the first sample of the packet and this
+// sample's timestamp is inferred by initial_input_timestamp_ +
+// cumulative_completed_samples / sample_rate_.
 class TimeSeriesFramerCalculator : public CalculatorBase {
 public:
  static ::mediapipe::Status GetContract(CalculatorContract* cc) {
@@ -86,11 +94,26 @@ class TimeSeriesFramerCalculator : public CalculatorBase {
  void FrameOutput(CalculatorContext* cc);

  Timestamp CurrentOutputTimestamp() {
+    if (use_local_timestamp_) {
+      return current_timestamp_;
+    }
+    return CumulativeOutputTimestamp();
+  }
+
+  Timestamp CumulativeOutputTimestamp() {
    return initial_input_timestamp_ +
           round(cumulative_completed_samples_ / sample_rate_ *
                 Timestamp::kTimestampUnitsPerSecond);
  }

+  // Returns the timestamp of a sample on a base, which is usually the time
+  // stamp of a packet.
+  Timestamp CurrentSampleTimestamp(const Timestamp& timestamp_base,
+                                   int64 number_of_samples) {
+    return timestamp_base + round(number_of_samples / sample_rate_ *
+                                  Timestamp::kTimestampUnitsPerSecond);
+  }
+
  // The number of input samples to advance after the current output frame is
  // emitted.
  int next_frame_step_samples() const {
@@ -118,14 +141,18 @@ class TimeSeriesFramerCalculator : public CalculatorBase {
  // any overlap).
  int64 cumulative_completed_samples_;
  Timestamp initial_input_timestamp_;
+  // The current timestamp is updated along with the incoming packets.
+  Timestamp current_timestamp_;
  int num_channels_;

  // Each entry in this deque consists of a single sample, i.e. a
-  // single column vector.
-  std::deque<Matrix> sample_buffer_;
+  // single column vector, and its timestamp.
+  std::deque<std::pair<Matrix, Timestamp>> sample_buffer_;

  bool use_window_;
  Matrix window_;
+
+  bool use_local_timestamp_;
 };
 REGISTER_CALCULATOR(TimeSeriesFramerCalculator);

@@ -133,7 +160,8 @@ void TimeSeriesFramerCalculator::EnqueueInput(CalculatorContext* cc) {
  const Matrix& input_frame = cc->Inputs().Index(0).Get<Matrix>();

  for (int i = 0; i < input_frame.cols(); ++i) {
-    sample_buffer_.emplace_back(input_frame.col(i));
+    sample_buffer_.emplace_back(std::make_pair(
+        input_frame.col(i), CurrentSampleTimestamp(cc->InputTimestamp(), i)));
  }

  cumulative_input_samples_ += input_frame.cols();
@@ -151,14 +179,16 @@ void TimeSeriesFramerCalculator::FrameOutput(CalculatorContext* cc) {
        new Matrix(num_channels_, frame_duration_samples_));
    for (int i = 0; i < std::min(frame_step_samples, frame_duration_samples_);
         ++i) {
-      output_frame->col(i) = sample_buffer_.front();
+      output_frame->col(i) = sample_buffer_.front().first;
+      current_timestamp_ = sample_buffer_.front().second;
      sample_buffer_.pop_front();
    }
    const int frame_overlap_samples =
        frame_duration_samples_ - frame_step_samples;
    if (frame_overlap_samples > 0) {
      for (int i = 0; i < frame_overlap_samples; ++i) {
-        output_frame->col(i + frame_step_samples) = sample_buffer_[i];
+        output_frame->col(i + frame_step_samples) = sample_buffer_[i].first;
+        current_timestamp_ = sample_buffer_[i].second;
      }
    } else {
      samples_still_to_drop_ = -frame_overlap_samples;
@@ -178,6 +208,7 @@ void TimeSeriesFramerCalculator::FrameOutput(CalculatorContext* cc) {
 ::mediapipe::Status TimeSeriesFramerCalculator::Process(CalculatorContext* cc) {
  if (initial_input_timestamp_ == Timestamp::Unstarted()) {
    initial_input_timestamp_ = cc->InputTimestamp();
+    current_timestamp_ = initial_input_timestamp_;
  }

  EnqueueInput(cc);
@@ -195,7 +226,8 @@ void TimeSeriesFramerCalculator::FrameOutput(CalculatorContext* cc) {
    std::unique_ptr<Matrix> output_frame(new Matrix);
    output_frame->setZero(num_channels_, frame_duration_samples_);
    for (int i = 0; i < sample_buffer_.size(); ++i) {
-      output_frame->col(i) = sample_buffer_[i];
+      output_frame->col(i) = sample_buffer_[i].first;
+      current_timestamp_ = sample_buffer_[i].second;
    }

    cc->Outputs().Index(0).Add(output_frame.release(),
@@ -206,8 +238,8 @@ void TimeSeriesFramerCalculator::FrameOutput(CalculatorContext* cc) {
 }

 ::mediapipe::Status TimeSeriesFramerCalculator::Open(CalculatorContext* cc) {
-  TimeSeriesFramerCalculatorOptions framer_options;
-  time_series_util::FillOptionsExtensionOrDie(cc->Options(), &framer_options);
+  TimeSeriesFramerCalculatorOptions framer_options =
+      cc->Options<TimeSeriesFramerCalculatorOptions>();

  RET_CHECK_GT(framer_options.frame_duration_seconds(), 0.0)
      << "Invalid or missing frame_duration_seconds. "
@@ -219,7 +251,7 @@ void TimeSeriesFramerCalculator::FrameOutput(CalculatorContext* cc) {
      << framer_options.frame_overlap_seconds();

  TimeSeriesHeader input_header;
-  RETURN_IF_ERROR(time_series_util::FillTimeSeriesHeaderIfValid(
+  MP_RETURN_IF_ERROR(time_series_util::FillTimeSeriesHeaderIfValid(
      cc->Inputs().Index(0).Header(), &input_header));

  sample_rate_ = input_header.sample_rate();
@@ -258,6 +290,7 @@ void TimeSeriesFramerCalculator::FrameOutput(CalculatorContext* cc) {
  cumulative_output_frames_ = 0;
  samples_still_to_drop_ = 0;
  initial_input_timestamp_ = Timestamp::Unstarted();
+  current_timestamp_ = Timestamp::Unstarted();

  std::vector<double> window_vector;
  use_window_ = false;
@@ -282,6 +315,7 @@ void TimeSeriesFramerCalculator::FrameOutput(CalculatorContext* cc) {
                                          frame_duration_samples_)
                  .cast<float>();
  }
+  use_local_timestamp_ = framer_options.use_local_timestamp();

  return ::mediapipe::OkStatus();
 }
@@ -62,4 +62,11 @@ message TimeSeriesFramerCalculatorOptions {
    HANN = 2;
  }
  optional WindowFunction window_function = 4 [default = NONE];
+
+  // If use_local_timestamp is true, the output packet's timestamp is based on
+  // the last sample of the packet and it's inferred from the latest input
+  // packet's timestamp.  If false, the output packet's timestamp is based on
+  // the cumulative timestamping, which is inferred from the intial input
+  // timestamp and the cumulative number of samples.
+  optional bool use_local_timestamp = 6 [default = false];
 }
@@ -35,6 +35,8 @@ namespace mediapipe {
 namespace {

 const int kInitialTimestampOffsetMicroseconds = 4;
+const int kGapBetweenPacketsInSeconds = 1;
+const int kUniversalInputPacketSize = 50;

 class TimeSeriesFramerCalculatorTest
    : public TimeSeriesCalculatorTest<TimeSeriesFramerCalculatorOptions> {
@@ -226,7 +228,7 @@ class TimeSeriesFramerCalculatorTest

 TEST_F(TimeSeriesFramerCalculatorTest, IntegerSampleDurationNoOverlap) {
  options_.set_frame_duration_seconds(100.0 / input_sample_rate_);
-  MEDIAPIPE_ASSERT_OK(Run());
+  MP_ASSERT_OK(Run());
  CheckOutput();
 }

@@ -234,7 +236,7 @@ TEST_F(TimeSeriesFramerCalculatorTest,
       IntegerSampleDurationNoOverlapHammingWindow) {
  options_.set_frame_duration_seconds(100.0 / input_sample_rate_);
  options_.set_window_function(TimeSeriesFramerCalculatorOptions::HAMMING);
-  MEDIAPIPE_ASSERT_OK(Run());
+  MP_ASSERT_OK(Run());
  CheckOutput();
 }

@@ -242,14 +244,14 @@ TEST_F(TimeSeriesFramerCalculatorTest,
       IntegerSampleDurationNoOverlapHannWindow) {
  options_.set_frame_duration_seconds(100.0 / input_sample_rate_);
  options_.set_window_function(TimeSeriesFramerCalculatorOptions::HANN);
-  MEDIAPIPE_ASSERT_OK(Run());
+  MP_ASSERT_OK(Run());
  CheckOutput();
 }

 TEST_F(TimeSeriesFramerCalculatorTest, IntegerSampleDurationAndOverlap) {
  options_.set_frame_duration_seconds(100.0 / input_sample_rate_);
  options_.set_frame_overlap_seconds(40.0 / input_sample_rate_);
-  MEDIAPIPE_ASSERT_OK(Run());
+  MP_ASSERT_OK(Run());
  CheckOutput();
 }

@@ -257,7 +259,7 @@ TEST_F(TimeSeriesFramerCalculatorTest, NonintegerSampleDurationAndOverlap) {
  options_.set_frame_duration_seconds(98.5 / input_sample_rate_);
  options_.set_frame_overlap_seconds(38.4 / input_sample_rate_);

-  MEDIAPIPE_ASSERT_OK(Run());
+  MP_ASSERT_OK(Run());
  CheckOutput();
 }

@@ -267,7 +269,7 @@ TEST_F(TimeSeriesFramerCalculatorTest, NegativeOverlapExactFrames) {
  // the 1100 input samples.
  options_.set_frame_duration_seconds(100.0 / input_sample_rate_);
  options_.set_frame_overlap_seconds(-10.0 / input_sample_rate_);
-  MEDIAPIPE_ASSERT_OK(Run());
+  MP_ASSERT_OK(Run());
  EXPECT_EQ(output().packets.size(), 10);
  CheckOutput();
 }
@@ -277,7 +279,7 @@ TEST_F(TimeSeriesFramerCalculatorTest, NegativeOverlapExactFramesLessSkip) {
  // the 1100 input samples.
  options_.set_frame_duration_seconds(100.0 / input_sample_rate_);
  options_.set_frame_overlap_seconds(-100.0 / input_sample_rate_);
-  MEDIAPIPE_ASSERT_OK(Run());
+  MP_ASSERT_OK(Run());
  EXPECT_EQ(output().packets.size(), 6);
  CheckOutput();
 }
@@ -287,7 +289,7 @@ TEST_F(TimeSeriesFramerCalculatorTest, NegativeOverlapWithPadding) {
  // on the sixth and last frame given 1100 sample input.
  options_.set_frame_duration_seconds(100.0 / input_sample_rate_);
  options_.set_frame_overlap_seconds(-100.0 / input_sample_rate_);
-  MEDIAPIPE_ASSERT_OK(Run());
+  MP_ASSERT_OK(Run());
  EXPECT_EQ(output().packets.size(), 6);
  CheckOutput();
 }
@@ -297,7 +299,7 @@ TEST_F(TimeSeriesFramerCalculatorTest, FixedFrameOverlap) {
  // results in ceil((1100 - 30) / 11) + 1 = 99 packets.
  options_.set_frame_duration_seconds(30 / input_sample_rate_);
  options_.set_frame_overlap_seconds((30.0 - 11.4) / input_sample_rate_);
-  MEDIAPIPE_ASSERT_OK(Run());
+  MP_ASSERT_OK(Run());
  EXPECT_EQ(output().packets.size(), 99);
  CheckOutput();
 }
@@ -308,7 +310,7 @@ TEST_F(TimeSeriesFramerCalculatorTest, VariableFrameOverlap) {
  options_.set_frame_duration_seconds(30 / input_sample_rate_);
  options_.set_frame_overlap_seconds((30 - 11.4) / input_sample_rate_);
  options_.set_emulate_fractional_frame_overlap(true);
-  MEDIAPIPE_ASSERT_OK(Run());
+  MP_ASSERT_OK(Run());
  EXPECT_EQ(output().packets.size(), 95);
  CheckOutput();
 }
@@ -319,7 +321,7 @@ TEST_F(TimeSeriesFramerCalculatorTest, VariableFrameSkip) {
  options_.set_frame_duration_seconds(30 / input_sample_rate_);
  options_.set_frame_overlap_seconds((30 - 41.4) / input_sample_rate_);
  options_.set_emulate_fractional_frame_overlap(true);
-  MEDIAPIPE_ASSERT_OK(Run());
+  MP_ASSERT_OK(Run());
  EXPECT_EQ(output().packets.size(), 27);
  CheckOutput();
 }
@@ -328,7 +330,7 @@ TEST_F(TimeSeriesFramerCalculatorTest, NoFinalPacketPadding) {
  options_.set_frame_duration_seconds(98.5 / input_sample_rate_);
  options_.set_pad_final_packet(false);

-  MEDIAPIPE_ASSERT_OK(Run());
+  MP_ASSERT_OK(Run());
  CheckOutput();
 }

@@ -369,7 +371,7 @@ class TimeSeriesFramerCalculatorWindowingSanityTest
    FillInputHeader();
    AppendInputPacket(new Matrix(Matrix::Ones(1, FrameDurationSamples())),
                      kInitialTimestampOffsetMicroseconds);
-    MEDIAPIPE_ASSERT_OK(RunGraph());
+    MP_ASSERT_OK(RunGraph());
    ASSERT_EQ(1, output().packets.size());
    ASSERT_NEAR(expected_average * FrameDurationSamples(),
                output().packets[0].Get<Matrix>().sum(), 1e-5);
@@ -391,5 +393,93 @@ TEST_F(TimeSeriesFramerCalculatorWindowingSanityTest, HannWindowSanityCheck) {
  RunAndTestSinglePacketAverage(0.5f);
 }

-}  // anonymous namespace
+// A simple test class that checks the local packet time stamp. This class
+// generate a series of packets with and without gaps between packets and tests
+// the behavior with cumulative timestamping and local packet timestamping.
+class TimeSeriesFramerCalculatorTimestampingTest
+    : public TimeSeriesFramerCalculatorTest {
+ protected:
+  // Creates test input and saves a reference copy.
+  void InitializeInputForTimeStampingTest() {
+    concatenated_input_samples_.resize(0, num_input_channels_);
+    num_input_samples_ = 0;
+    for (int i = 0; i < 10; ++i) {
+      // This range of packet sizes was chosen such that some input
+      // packets will be smaller than the output packet size and other
+      // input packets will be larger.
+      int packet_size = kUniversalInputPacketSize;
+      double timestamp_seconds = kInitialTimestampOffsetMicroseconds * 1.0e-6 +
+                                 num_input_samples_ / input_sample_rate_;
+      if (options_.use_local_timestamp()) {
+        timestamp_seconds += kGapBetweenPacketsInSeconds * i;
+      }
+
+      Matrix* data_frame =
+          NewTestFrame(num_input_channels_, packet_size, timestamp_seconds);
+
+      AppendInputPacket(data_frame, round(timestamp_seconds *
+                                          Timestamp::kTimestampUnitsPerSecond));
+      num_input_samples_ += packet_size;
+    }
+  }
+
+  void CheckOutputTimestamps() {
+    int num_full_packets = output().packets.size();
+    if (options_.pad_final_packet()) {
+      num_full_packets -= 1;
+    }
+
+    int64 num_samples = 0;
+    for (int packet_num = 0; packet_num < num_full_packets; ++packet_num) {
+      const Packet& packet = output().packets[packet_num];
+      num_samples += FrameDurationSamples();
+      double expected_timestamp =
+          options_.use_local_timestamp()
+              ? GetExpectedLocalTimestampForSample(num_samples - 1)
+              : GetExpectedCumulativeTimestamp(num_samples - 1);
+      ASSERT_NEAR(packet.Timestamp().Seconds(), expected_timestamp, 1e-10);
+    }
+  }
+
+  ::mediapipe::Status RunTimestampTest() {
+    InitializeGraph();
+    InitializeInputForTimeStampingTest();
+    FillInputHeader();
+    return RunGraph();
+  }
+
+ private:
+  // Returns the timestamp in seconds based on local timestamping.
+  double GetExpectedLocalTimestampForSample(int sample_index) {
+    return kInitialTimestampOffsetMicroseconds * 1.0e-6 +
+           sample_index / input_sample_rate_ +
+           (sample_index / kUniversalInputPacketSize) *
+               kGapBetweenPacketsInSeconds;
+  }
+
+  // Returns the timestamp inseconds based on cumulative timestamping.
+  double GetExpectedCumulativeTimestamp(int sample_index) {
+    return kInitialTimestampOffsetMicroseconds * 1.0e-6 +
+           sample_index / FrameDurationSamples() * FrameDurationSamples() /
+               input_sample_rate_;
+  }
+};
+
+TEST_F(TimeSeriesFramerCalculatorTimestampingTest, UseLocalTimeStamp) {
+  options_.set_frame_duration_seconds(100.0 / input_sample_rate_);
+  options_.set_use_local_timestamp(true);
+
+  MP_ASSERT_OK(RunTimestampTest());
+  CheckOutputTimestamps();
+}
+
+TEST_F(TimeSeriesFramerCalculatorTimestampingTest, UseCumulativeTimeStamp) {
+  options_.set_frame_duration_seconds(100.0 / input_sample_rate_);
+  options_.set_use_local_timestamp(false);
+
+  MP_ASSERT_OK(RunTimestampTest());
+  CheckOutputTimestamps();
+}
+
+}  // namespace
 }  // namespace mediapipe
@@ -13,12 +13,12 @@
 # limitations under the License.
 #

+load("//mediapipe/framework/port:build_config.bzl", "mediapipe_cc_proto_library")
+
 licenses(["notice"])  # Apache 2.0

 package(default_visibility = ["//visibility:private"])

-load("//mediapipe/framework/port:build_config.bzl", "mediapipe_cc_proto_library")
-
 proto_library(
    name = "concatenate_vector_calculator_proto",
    srcs = ["concatenate_vector_calculator.proto"],
@@ -26,6 +26,13 @@ proto_library(
    deps = ["//mediapipe/framework:calculator_proto"],
 )

+proto_library(
+    name = "dequantize_byte_array_calculator_proto",
+    srcs = ["dequantize_byte_array_calculator.proto"],
+    visibility = ["//visibility:public"],
+    deps = ["//mediapipe/framework:calculator_proto"],
+)
+
 proto_library(
    name = "packet_cloner_calculator_proto",
    srcs = ["packet_cloner_calculator.proto"],
@@ -40,6 +47,13 @@ proto_library(
    deps = ["//mediapipe/framework:calculator_proto"],
 )

+proto_library(
+    name = "packet_thinner_calculator_proto",
+    srcs = ["packet_thinner_calculator.proto"],
+    visibility = ["//visibility:public"],
+    deps = ["//mediapipe/framework:calculator_proto"],
+)
+
 proto_library(
    name = "split_vector_calculator_proto",
    srcs = ["split_vector_calculator.proto"],
@@ -72,11 +86,27 @@ proto_library(
    ],
 )

+proto_library(
+    name = "constant_side_packet_calculator_proto",
+    srcs = ["constant_side_packet_calculator.proto"],
+    visibility = ["//visibility:public"],
+    deps = [
+        "//mediapipe/framework:calculator_proto",
+    ],
+)
+
+proto_library(
+    name = "clip_vector_size_calculator_proto",
+    srcs = ["clip_vector_size_calculator.proto"],
+    visibility = ["//visibility:public"],
+    deps = ["//mediapipe/framework:calculator_proto"],
+)
+
 mediapipe_cc_proto_library(
    name = "packet_cloner_calculator_cc_proto",
    srcs = ["packet_cloner_calculator.proto"],
    cc_deps = ["//mediapipe/framework:calculator_cc_proto"],
-    visibility = ["//mediapipe:__subpackages__"],
+    visibility = ["//visibility:public"],
    deps = [":packet_cloner_calculator_proto"],
 )

@@ -84,15 +114,23 @@ mediapipe_cc_proto_library(
    name = "packet_resampler_calculator_cc_proto",
    srcs = ["packet_resampler_calculator.proto"],
    cc_deps = ["//mediapipe/framework:calculator_cc_proto"],
-    visibility = ["//mediapipe:__subpackages__"],
+    visibility = ["//visibility:public"],
    deps = [":packet_resampler_calculator_proto"],
 )

+mediapipe_cc_proto_library(
+    name = "packet_thinner_calculator_cc_proto",
+    srcs = ["packet_thinner_calculator.proto"],
+    cc_deps = ["//mediapipe/framework:calculator_cc_proto"],
+    visibility = ["//visibility:public"],
+    deps = [":packet_thinner_calculator_proto"],
+)
+
 mediapipe_cc_proto_library(
    name = "split_vector_calculator_cc_proto",
    srcs = ["split_vector_calculator.proto"],
    cc_deps = ["//mediapipe/framework:calculator_cc_proto"],
-    visibility = ["//mediapipe:__subpackages__"],
+    visibility = ["//visibility:public"],
    deps = [":split_vector_calculator_proto"],
 )

@@ -104,11 +142,27 @@ mediapipe_cc_proto_library(
    deps = [":concatenate_vector_calculator_proto"],
 )

+mediapipe_cc_proto_library(
+    name = "clip_vector_size_calculator_cc_proto",
+    srcs = ["clip_vector_size_calculator.proto"],
+    cc_deps = ["//mediapipe/framework:calculator_cc_proto"],
+    visibility = ["//visibility:public"],
+    deps = [":clip_vector_size_calculator_proto"],
+)
+
+mediapipe_cc_proto_library(
+    name = "dequantize_byte_array_calculator_cc_proto",
+    srcs = ["dequantize_byte_array_calculator.proto"],
+    cc_deps = ["//mediapipe/framework:calculator_cc_proto"],
+    visibility = ["//visibility:public"],
+    deps = [":dequantize_byte_array_calculator_proto"],
+)
+
 mediapipe_cc_proto_library(
    name = "quantize_float_vector_calculator_cc_proto",
    srcs = ["quantize_float_vector_calculator.proto"],
    cc_deps = ["//mediapipe/framework:calculator_cc_proto"],
-    visibility = ["//mediapipe:__subpackages__"],
+    visibility = ["//visibility:public"],
    deps = [":quantize_float_vector_calculator_proto"],
 )

@@ -116,7 +170,7 @@ mediapipe_cc_proto_library(
    name = "sequence_shift_calculator_cc_proto",
    srcs = ["sequence_shift_calculator.proto"],
    cc_deps = ["//mediapipe/framework:calculator_cc_proto"],
-    visibility = ["//mediapipe:__subpackages__"],
+    visibility = ["//visibility:public"],
    deps = [":sequence_shift_calculator_proto"],
 )

@@ -124,10 +178,18 @@ mediapipe_cc_proto_library(
    name = "gate_calculator_cc_proto",
    srcs = ["gate_calculator.proto"],
    cc_deps = ["//mediapipe/framework:calculator_cc_proto"],
-    visibility = ["//mediapipe:__subpackages__"],
+    visibility = ["//visibility:public"],
    deps = [":gate_calculator_proto"],
 )

+mediapipe_cc_proto_library(
+    name = "constant_side_packet_calculator_cc_proto",
+    srcs = ["constant_side_packet_calculator.proto"],
+    cc_deps = ["//mediapipe/framework:calculator_cc_proto"],
+    visibility = ["//visibility:public"],
+    deps = [":constant_side_packet_calculator_proto"],
+)
+
 cc_library(
    name = "add_header_calculator",
    srcs = ["add_header_calculator.cc"],
@@ -135,6 +197,7 @@ cc_library(
    deps = [
        "//mediapipe/framework:calculator_framework",
        "//mediapipe/framework/port:logging",
+        "//mediapipe/framework/port:status",
    ],
    alwayslink = 1,
 )
@@ -154,6 +217,71 @@ cc_test(
    ],
 )

+cc_library(
+    name = "begin_loop_calculator",
+    srcs = ["begin_loop_calculator.cc"],
+    hdrs = ["begin_loop_calculator.h"],
+    visibility = ["//visibility:public"],
+    deps = [
+        "//mediapipe/framework:calculator_context",
+        "//mediapipe/framework:calculator_contract",
+        "//mediapipe/framework:calculator_framework",
+        "//mediapipe/framework:collection_item_id",
+        "//mediapipe/framework:packet",
+        "//mediapipe/framework/formats:detection_cc_proto",
+        "//mediapipe/framework/formats:landmark_cc_proto",
+        "//mediapipe/framework/formats:matrix",
+        "//mediapipe/framework/formats:rect_cc_proto",
+        "//mediapipe/framework/port:integral_types",
+        "//mediapipe/framework/port:ret_check",
+        "//mediapipe/framework/port:status",
+        "@com_google_absl//absl/memory",
+    ],
+    alwayslink = 1,
+)
+
+cc_library(
+    name = "end_loop_calculator",
+    srcs = ["end_loop_calculator.cc"],
+    hdrs = ["end_loop_calculator.h"],
+    visibility = ["//visibility:public"],
+    deps = [
+        "//mediapipe/framework:calculator_context",
+        "//mediapipe/framework:calculator_contract",
+        "//mediapipe/framework:calculator_framework",
+        "//mediapipe/framework:collection_item_id",
+        "//mediapipe/framework:packet",
+        "//mediapipe/framework/formats:classification_cc_proto",
+        "//mediapipe/framework/formats:landmark_cc_proto",
+        "//mediapipe/framework/formats:rect_cc_proto",
+        "//mediapipe/framework/port:integral_types",
+        "//mediapipe/framework/port:ret_check",
+        "//mediapipe/framework/port:status",
+        "//mediapipe/util:render_data_cc_proto",
+        "@org_tensorflow//tensorflow/lite:framework",
+    ],
+    alwayslink = 1,
+)
+
+cc_test(
+    name = "begin_end_loop_calculator_graph_test",
+    srcs = ["begin_end_loop_calculator_graph_test.cc"],
+    deps = [
+        ":begin_loop_calculator",
+        ":end_loop_calculator",
+        ":gate_calculator",
+        "//mediapipe/framework:calculator_context",
+        "//mediapipe/framework:calculator_contract",
+        "//mediapipe/framework:calculator_framework",
+        "//mediapipe/framework:packet",
+        "//mediapipe/framework/port:gtest_main",
+        "//mediapipe/framework/port:integral_types",
+        "//mediapipe/framework/port:parse_text_proto",
+        "//mediapipe/framework/port:status",
+        "@com_google_absl//absl/memory",
+    ],
+)
+
 cc_library(
    name = "concatenate_vector_calculator",
    srcs = ["concatenate_vector_calculator.cc"],
@@ -162,10 +290,17 @@ cc_library(
    deps = [
        ":concatenate_vector_calculator_cc_proto",
        "//mediapipe/framework:calculator_framework",
+        "//mediapipe/framework/formats:landmark_cc_proto",
        "//mediapipe/framework/port:ret_check",
        "//mediapipe/framework/port:status",
        "@org_tensorflow//tensorflow/lite:framework",
-    ],
+    ] + select({
+        "//mediapipe/gpu:disable_gpu": [],
+        "//mediapipe:ios": [],
+        "//conditions:default": [
+            "@org_tensorflow//tensorflow/lite/delegates/gpu/gl:gl_buffer",
+        ],
+    }),
    alwayslink = 1,
 )

@@ -186,6 +321,50 @@ cc_test(
    srcs = ["concatenate_vector_calculator_test.cc"],
    deps = [
        ":concatenate_vector_calculator",
+        "//mediapipe/framework:calculator_framework",
+        "//mediapipe/framework:calculator_runner",
+        "//mediapipe/framework:timestamp",
+        "//mediapipe/framework/port:gtest_main",
+        "//mediapipe/framework/port:parse_text_proto",
+        "//mediapipe/framework/port:status",
+        "@com_google_absl//absl/strings",
+    ],
+)
+
+cc_library(
+    name = "clip_vector_size_calculator",
+    srcs = ["clip_vector_size_calculator.cc"],
+    hdrs = ["clip_vector_size_calculator.h"],
+    visibility = ["//visibility:public"],
+    deps = [
+        ":clip_vector_size_calculator_cc_proto",
+        "//mediapipe/framework:calculator_framework",
+        "//mediapipe/framework/formats:detection_cc_proto",
+        "//mediapipe/framework/formats:rect_cc_proto",
+        "//mediapipe/framework/port:ret_check",
+        "//mediapipe/framework/port:status",
+        "@org_tensorflow//tensorflow/lite:framework",
+    ],
+    alwayslink = 1,
+)
+
+cc_library(
+    name = "clip_detection_vector_size_calculator",
+    srcs = ["clip_detection_vector_size_calculator.cc"],
+    visibility = ["//visibility:public"],
+    deps = [
+        ":clip_vector_size_calculator",
+        "//mediapipe/framework:calculator_framework",
+        "//mediapipe/framework/formats:detection_cc_proto",
+    ],
+    alwayslink = 1,
+)
+
+cc_test(
+    name = "clip_vector_size_calculator_test",
+    srcs = ["clip_vector_size_calculator_test.cc"],
+    deps = [
+        ":clip_vector_size_calculator",
        "//mediapipe/calculators/core:packet_resampler_calculator_cc_proto",
        "//mediapipe/framework:calculator_framework",
        "//mediapipe/framework:calculator_runner",
@@ -278,7 +457,7 @@ cc_library(
        "//visibility:public",
    ],
    deps = [
-        "//mediapipe/calculators/core:packet_cloner_calculator_cc_proto",
+        ":packet_cloner_calculator_cc_proto",
        "//mediapipe/framework:calculator_framework",
        "@com_google_absl//absl/strings",
    ],
@@ -309,6 +488,37 @@ cc_test(
    ],
 )

+cc_library(
+    name = "packet_thinner_calculator",
+    srcs = ["packet_thinner_calculator.cc"],
+    visibility = ["//visibility:public"],
+    deps = [
+        "//mediapipe/calculators/core:packet_thinner_calculator_cc_proto",
+        "//mediapipe/framework:calculator_context",
+        "//mediapipe/framework:calculator_framework",
+        "//mediapipe/framework/formats:video_stream_header",
+        "//mediapipe/framework/port:integral_types",
+        "//mediapipe/framework/port:logging",
+        "//mediapipe/framework/port:status",
+    ],
+    alwayslink = 1,
+)
+
+cc_test(
+    name = "packet_thinner_calculator_test",
+    srcs = ["packet_thinner_calculator_test.cc"],
+    deps = [
+        ":packet_thinner_calculator",
+        "//mediapipe/calculators/core:packet_thinner_calculator_cc_proto",
+        "//mediapipe/framework:calculator_framework",
+        "//mediapipe/framework:calculator_runner",
+        "//mediapipe/framework/formats:video_stream_header",
+        "//mediapipe/framework/port:gtest_main",
+        "//mediapipe/framework/port:integral_types",
+        "@com_google_absl//absl/strings",
+    ],
+)
+
 cc_library(
    name = "pass_through_calculator",
    srcs = ["pass_through_calculator.cc"],
@@ -380,6 +590,48 @@ cc_library(
    alwayslink = 1,
 )

+cc_library(
+    name = "string_to_int_calculator",
+    srcs = ["string_to_int_calculator.cc"],
+    visibility = ["//visibility:public"],
+    deps = [
+        "//mediapipe/framework:calculator_framework",
+        "//mediapipe/framework/port:integral_types",
+        "//mediapipe/framework/port:status",
+        "@com_google_absl//absl/strings",
+    ],
+    alwayslink = 1,
+)
+
+cc_library(
+    name = "side_packet_to_stream_calculator",
+    srcs = ["side_packet_to_stream_calculator.cc"],
+    visibility = ["//visibility:public"],
+    deps = [
+        "//mediapipe/framework:calculator_framework",
+        "//mediapipe/framework/port:logging",
+        "//mediapipe/framework/port:ret_check",
+        "//mediapipe/framework/port:status",
+    ],
+    alwayslink = 1,
+)
+
+cc_test(
+    name = "side_packet_to_stream_calculator_test",
+    srcs = ["side_packet_to_stream_calculator_test.cc"],
+    deps = [
+        ":side_packet_to_stream_calculator",
+        "//mediapipe/framework:calculator_framework",
+        "//mediapipe/framework/port:gtest_main",
+        "//mediapipe/framework/port:integral_types",
+        "//mediapipe/framework/port:parse_text_proto",
+        "//mediapipe/framework/port:status",
+        "//mediapipe/framework/tool:options_util",
+        "@com_google_absl//absl/memory",
+        "@com_google_absl//absl/strings",
+    ],
+)
+
 cc_test(
    name = "immediate_mux_calculator_test",
    srcs = ["immediate_mux_calculator_test.cc"],
@@ -404,6 +656,7 @@ cc_test(
 cc_library(
    name = "packet_resampler_calculator",
    srcs = ["packet_resampler_calculator.cc"],
+    hdrs = ["packet_resampler_calculator.h"],
    visibility = [
        "//visibility:public",
    ],
@@ -427,17 +680,17 @@ cc_library(
 cc_test(
    name = "packet_resampler_calculator_test",
    timeout = "short",
-    srcs = ["packet_resampler_calculator_test.cc"],
+    srcs = [
+        "packet_resampler_calculator_test.cc",
+    ],
    deps = [
        ":packet_resampler_calculator",
        "//mediapipe/calculators/core:packet_resampler_calculator_cc_proto",
        "//mediapipe/framework:calculator_framework",
        "//mediapipe/framework:calculator_runner",
-        "//mediapipe/framework:timestamp",
        "//mediapipe/framework/formats:video_stream_header",
        "//mediapipe/framework/port:gtest_main",
        "//mediapipe/framework/port:parse_text_proto",
-        "//mediapipe/framework/port:status",
        "@com_google_absl//absl/strings",
    ],
 )
@@ -446,15 +699,17 @@ cc_test(
    name = "previous_loopback_calculator_test",
    srcs = ["previous_loopback_calculator_test.cc"],
    deps = [
+        ":gate_calculator",
+        ":make_pair_calculator",
+        ":pass_through_calculator",
        ":previous_loopback_calculator",
-        "//mediapipe/calculators/core:make_pair_calculator",
-        "//mediapipe/calculators/core:pass_through_calculator",
        "//mediapipe/framework:calculator_framework",
        "//mediapipe/framework:calculator_runner",
        "//mediapipe/framework:timestamp",
        "//mediapipe/framework/port:gtest_main",
        "//mediapipe/framework/port:integral_types",
        "//mediapipe/framework/port:parse_text_proto",
+        "//mediapipe/framework/port:status",
        "//mediapipe/framework/stream_handler:immediate_input_stream_handler",
        "//mediapipe/framework/tool:sink",
        "@com_google_absl//absl/time",
@@ -522,13 +777,23 @@ cc_library(
    visibility = ["//visibility:public"],
    deps = [
        ":split_vector_calculator_cc_proto",
+        "//mediapipe/framework/formats:detection_cc_proto",
        "//mediapipe/framework:calculator_framework",
+        "//mediapipe/framework/formats:landmark_cc_proto",
+        "//mediapipe/framework/formats:rect_cc_proto",
+        "//mediapipe/framework/formats:matrix",
        "//mediapipe/framework/port:ret_check",
        "//mediapipe/framework/port:status",
        "//mediapipe/util:resource_util",
        "@org_tensorflow//tensorflow/lite:framework",
        "@org_tensorflow//tensorflow/lite/kernels:builtin_ops",
-    ],
+    ] + select({
+        "//mediapipe/gpu:disable_gpu": [],
+        "//mediapipe:ios": [],
+        "//conditions:default": [
+            "@org_tensorflow//tensorflow/lite/delegates/gpu/gl:gl_buffer",
+        ],
+    }),
    alwayslink = 1,
 )

@@ -550,6 +815,32 @@ cc_test(
    ],
 )

+cc_library(
+    name = "dequantize_byte_array_calculator",
+    srcs = ["dequantize_byte_array_calculator.cc"],
+    visibility = ["//visibility:public"],
+    deps = [
+        ":dequantize_byte_array_calculator_cc_proto",
+        "//mediapipe/framework:calculator_context",
+        "//mediapipe/framework:calculator_framework",
+        "//mediapipe/framework/port:status",
+    ],
+    alwayslink = 1,
+)
+
+cc_test(
+    name = "dequantize_byte_array_calculator_test",
+    srcs = ["dequantize_byte_array_calculator_test.cc"],
+    deps = [
+        ":dequantize_byte_array_calculator",
+        "//mediapipe/framework:calculator_framework",
+        "//mediapipe/framework:calculator_runner",
+        "//mediapipe/framework/port:gtest_main",
+        "//mediapipe/framework/port:parse_text_proto",
+        "//mediapipe/framework/port:status",
+    ],
+)
+
 cc_library(
    name = "quantize_float_vector_calculator",
    srcs = ["quantize_float_vector_calculator.cc"],
@@ -627,6 +918,41 @@ cc_test(
    ],
 )

+cc_library(
+    name = "matrix_to_vector_calculator",
+    srcs = ["matrix_to_vector_calculator.cc"],
+    visibility = ["//visibility:public"],
+    deps = [
+        "//mediapipe/framework:calculator_framework",
+        "//mediapipe/framework/formats:matrix",
+        "//mediapipe/framework/port:integral_types",
+        "//mediapipe/framework/port:logging",
+        "//mediapipe/framework/port:parse_text_proto",
+        "//mediapipe/framework/tool:status_util",
+        "//mediapipe/util:time_series_util",
+        "@com_google_absl//absl/memory",
+        "@eigen_archive//:eigen",
+    ],
+    alwayslink = 1,
+)
+
+cc_test(
+    name = "matrix_to_vector_calculator_test",
+    srcs = ["matrix_to_vector_calculator_test.cc"],
+    deps = [
+        ":matrix_to_vector_calculator",
+        "//mediapipe/framework:calculator_runner",
+        "//mediapipe/framework/formats:matrix",
+        "//mediapipe/framework/port:gtest_main",
+        "//mediapipe/framework/port:integral_types",
+        "//mediapipe/framework/port:parse_text_proto",
+        "//mediapipe/framework/port:status",
+        "//mediapipe/framework/tool:validate_type",
+        "//mediapipe/util:time_series_test_util",
+        "//mediapipe/util:time_series_util",
+    ],
+)
+
 cc_library(
    name = "merge_calculator",
    srcs = ["merge_calculator.cc"],
@@ -651,3 +977,56 @@ cc_test(
        "//mediapipe/framework/port:status",
    ],
 )
+
+cc_library(
+    name = "stream_to_side_packet_calculator",
+    srcs = ["stream_to_side_packet_calculator.cc"],
+    visibility = ["//visibility:public"],
+    deps = [
+        "//mediapipe/framework:calculator_framework",
+        "//mediapipe/framework:timestamp",
+        "//mediapipe/framework/port:status",
+    ],
+    alwayslink = 1,
+)
+
+cc_test(
+    name = "stream_to_side_packet_calculator_test",
+    srcs = ["stream_to_side_packet_calculator_test.cc"],
+    deps = [
+        ":stream_to_side_packet_calculator",
+        "//mediapipe/framework:calculator_runner",
+        "//mediapipe/framework:packet",
+        "//mediapipe/framework:timestamp",
+        "//mediapipe/framework/port:gtest_main",
+        "//mediapipe/framework/port:status",
+        "@com_google_absl//absl/memory",
+    ],
+)
+
+cc_library(
+    name = "constant_side_packet_calculator",
+    srcs = ["constant_side_packet_calculator.cc"],
+    visibility = ["//visibility:public"],
+    deps = [
+        ":constant_side_packet_calculator_cc_proto",
+        "//mediapipe/framework:calculator_framework",
+        "//mediapipe/framework:collection_item_id",
+        "//mediapipe/framework/port:ret_check",
+        "//mediapipe/framework/port:status",
+    ],
+    alwayslink = 1,
+)
+
+cc_test(
+    name = "constant_side_packet_calculator_test",
+    srcs = ["constant_side_packet_calculator_test.cc"],
+    deps = [
+        ":constant_side_packet_calculator",
+        "//mediapipe/framework:calculator_framework",
+        "//mediapipe/framework/port:gtest_main",
+        "//mediapipe/framework/port:parse_text_proto",
+        "//mediapipe/framework/port:status",
+        "@com_google_absl//absl/strings",
+    ],
+)
@@ -13,11 +13,12 @@
 // limitations under the License.

 #include "mediapipe/framework/calculator_framework.h"
+#include "mediapipe/framework/port/canonical_errors.h"
 #include "mediapipe/framework/port/logging.h"

 namespace mediapipe {

-// Attach the header from one stream to another stream.
+// Attach the header from a stream or side input to another stream.
 //
 // The header stream (tag HEADER) must not have any packets in it.
 //
@@ -25,17 +26,53 @@ namespace mediapipe {
 // calculator to not need a header or to accept a separate stream with
 // a header, that would be more future proof.
 //
+// Example usage 1:
+// node {
+//   calculator: "AddHeaderCalculator"
+//   input_stream: "DATA:audio"
+//   input_stream: "HEADER:audio_header"
+//   output_stream: "audio_with_header"
+// }
+//
+// Example usage 2:
+// node {
+//   calculator: "AddHeaderCalculator"
+//   input_stream: "DATA:audio"
+//   input_side_packet: "HEADER:audio_header"
+//   output_stream: "audio_with_header"
+// }
+//
 class AddHeaderCalculator : public CalculatorBase {
 public:
  static ::mediapipe::Status GetContract(CalculatorContract* cc) {
-    cc->Inputs().Tag("HEADER").SetNone();
+    bool has_side_input = false;
+    bool has_header_stream = false;
+    if (cc->InputSidePackets().HasTag("HEADER")) {
+      cc->InputSidePackets().Tag("HEADER").SetAny();
+      has_side_input = true;
+    }
+    if (cc->Inputs().HasTag("HEADER")) {
+      cc->Inputs().Tag("HEADER").SetNone();
+      has_header_stream = true;
+    }
+    if (has_side_input == has_header_stream) {
+      return mediapipe::InvalidArgumentError(
+          "Header must be provided via exactly one of side input and input "
+          "stream");
+    }
    cc->Inputs().Tag("DATA").SetAny();
    cc->Outputs().Index(0).SetSameAs(&cc->Inputs().Tag("DATA"));
    return ::mediapipe::OkStatus();
  }

  ::mediapipe::Status Open(CalculatorContext* cc) override {
-    const Packet& header = cc->Inputs().Tag("HEADER").Header();
+    Packet header;
+    if (cc->InputSidePackets().HasTag("HEADER")) {
+      header = cc->InputSidePackets().Tag("HEADER");
+    }
+    if (cc->Inputs().HasTag("HEADER")) {
+      header = cc->Inputs().Tag("HEADER").Header();
+    }
    if (!header.IsEmpty()) {
      cc->Outputs().Index(0).SetHeader(header);
    }
@@ -14,8 +14,10 @@

 #include "mediapipe/framework/calculator_framework.h"
 #include "mediapipe/framework/calculator_runner.h"
+#include "mediapipe/framework/port/canonical_errors.h"
 #include "mediapipe/framework/port/gmock.h"
 #include "mediapipe/framework/port/gtest.h"
+#include "mediapipe/framework/port/status.h"
 #include "mediapipe/framework/port/status_matchers.h"
 #include "mediapipe/framework/timestamp.h"
 #include "mediapipe/framework/tool/validate_type.h"
@@ -24,7 +26,7 @@ namespace mediapipe {

 class AddHeaderCalculatorTest : public ::testing::Test {};

-TEST_F(AddHeaderCalculatorTest, Works) {
+TEST_F(AddHeaderCalculatorTest, HeaderStream) {
  CalculatorGraphConfig::Node node;
  node.set_calculator("AddHeaderCalculator");
  node.add_input_stream("HEADER:header_stream");
@@ -42,7 +44,7 @@ TEST_F(AddHeaderCalculatorTest, Works) {
  }

  // Run calculator.
-  MEDIAPIPE_ASSERT_OK(runner.Run());
+  MP_ASSERT_OK(runner.Run());

  ASSERT_EQ(1, runner.Outputs().NumEntries());

@@ -69,7 +71,7 @@ TEST_F(AddHeaderCalculatorTest, HandlesEmptyHeaderStream) {

  // No header and no packets.
  // Run calculator.
-  MEDIAPIPE_ASSERT_OK(runner.Run());
+  MP_ASSERT_OK(runner.Run());
  EXPECT_TRUE(runner.Outputs().Index(0).header.IsEmpty());
 }

@@ -96,4 +98,62 @@ TEST_F(AddHeaderCalculatorTest, NoPacketsOnHeaderStream) {
  ASSERT_FALSE(runner.Run().ok());
 }

+TEST_F(AddHeaderCalculatorTest, InputSidePacket) {
+  CalculatorGraphConfig::Node node;
+  node.set_calculator("AddHeaderCalculator");
+  node.add_input_stream("DATA:data_stream");
+  node.add_output_stream("merged_stream");
+  node.add_input_side_packet("HEADER:header");
+
+  CalculatorRunner runner(node);
+
+  // Set header and add 5 packets.
+  runner.MutableSidePackets()->Tag("HEADER") =
+      Adopt(new std::string("my_header"));
+  for (int i = 0; i < 5; ++i) {
+    Packet packet = Adopt(new int(i)).At(Timestamp(i * 1000));
+    runner.MutableInputs()->Tag("DATA").packets.push_back(packet);
+  }
+
+  // Run calculator.
+  MP_ASSERT_OK(runner.Run());
+
+  ASSERT_EQ(1, runner.Outputs().NumEntries());
+
+  // Test output.
+  EXPECT_EQ(std::string("my_header"),
+            runner.Outputs().Index(0).header.Get<std::string>());
+  const std::vector<Packet>& output_packets = runner.Outputs().Index(0).packets;
+  ASSERT_EQ(5, output_packets.size());
+  for (int i = 0; i < 5; ++i) {
+    const int val = output_packets[i].Get<int>();
+    EXPECT_EQ(i, val);
+    EXPECT_EQ(Timestamp(i * 1000), output_packets[i].Timestamp());
+  }
+}
+
+TEST_F(AddHeaderCalculatorTest, UsingBothSideInputAndStream) {
+  CalculatorGraphConfig::Node node;
+  node.set_calculator("AddHeaderCalculator");
+  node.add_input_stream("HEADER:header_stream");
+  node.add_input_stream("DATA:data_stream");
+  node.add_output_stream("merged_stream");
+  node.add_input_side_packet("HEADER:header");
+
+  CalculatorRunner runner(node);
+
+  // Set both headers and add 5 packets.
+  runner.MutableSidePackets()->Tag("HEADER") =
+      Adopt(new std::string("my_header"));
+  runner.MutableSidePackets()->Tag("HEADER") =
+      Adopt(new std::string("my_header"));
+  for (int i = 0; i < 5; ++i) {
+    Packet packet = Adopt(new int(i)).At(Timestamp(i * 1000));
+    runner.MutableInputs()->Tag("DATA").packets.push_back(packet);
+  }
+
+  // Run should fail because header can only be provided one way.
+  EXPECT_EQ(runner.Run().code(), ::mediapipe::InvalidArgumentError("").code());
+}
+
 }  // namespace mediapipe
@@ -0,0 +1,448 @@
+// Copyright 2019 The MediaPipe Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include <string>
+#include <vector>
+
+#include "absl/memory/memory.h"
+#include "mediapipe/calculators/core/begin_loop_calculator.h"
+#include "mediapipe/calculators/core/end_loop_calculator.h"
+#include "mediapipe/framework/calculator_contract.h"
+#include "mediapipe/framework/calculator_framework.h"
+#include "mediapipe/framework/packet.h"
+#include "mediapipe/framework/port/gmock.h"
+#include "mediapipe/framework/port/gtest.h"
+#include "mediapipe/framework/port/integral_types.h"
+#include "mediapipe/framework/port/parse_text_proto.h"
+#include "mediapipe/framework/port/status_matchers.h"  // NOLINT
+
+namespace mediapipe {
+namespace {
+
+MATCHER_P2(PacketOfIntsEq, timestamp, value, "") {
+  Timestamp actual_timestamp = arg.Timestamp();
+  const auto& actual_value = arg.template Get<std::vector<int>>();
+  return testing::Value(actual_timestamp, testing::Eq(timestamp)) &&
+         testing::Value(actual_value, testing::ElementsAreArray(value));
+}
+
+typedef BeginLoopCalculator<std::vector<int>> BeginLoopIntegerCalculator;
+REGISTER_CALCULATOR(BeginLoopIntegerCalculator);
+
+class IncrementCalculator : public CalculatorBase {
+ public:
+  static ::mediapipe::Status GetContract(CalculatorContract* cc) {
+    cc->Inputs().Index(0).Set<int>();
+    cc->Outputs().Index(0).Set<int>();
+    return ::mediapipe::OkStatus();
+  }
+
+  ::mediapipe::Status Open(CalculatorContext* cc) override {
+    cc->SetOffset(TimestampDiff(0));
+    return ::mediapipe::OkStatus();
+  }
+
+  ::mediapipe::Status Process(CalculatorContext* cc) override {
+    const int& input_int = cc->Inputs().Index(0).Get<int>();
+    auto output_int = absl::make_unique<int>(input_int + 1);
+    cc->Outputs().Index(0).Add(output_int.release(), cc->InputTimestamp());
+    return ::mediapipe::OkStatus();
+  }
+};
+
+REGISTER_CALCULATOR(IncrementCalculator);
+
+typedef EndLoopCalculator<std::vector<int>> EndLoopIntegersCalculator;
+REGISTER_CALCULATOR(EndLoopIntegersCalculator);
+
+class BeginEndLoopCalculatorGraphTest : public ::testing::Test {
+ protected:
+  void SetUp() override {
+    auto graph_config = ParseTextProtoOrDie<CalculatorGraphConfig>(
+        R"(
+          num_threads: 4
+          input_stream: "ints"
+          node {
+            calculator: "BeginLoopIntegerCalculator"
+            input_stream: "ITERABLE:ints"
+            output_stream: "ITEM:int"
+            output_stream: "BATCH_END:timestamp"
+          }
+          node {
+            calculator: "IncrementCalculator"
+            input_stream: "int"
+            output_stream: "int_plus_one"
+          }
+          node {
+            calculator: "EndLoopIntegersCalculator"
+            input_stream: "ITEM:int_plus_one"
+            input_stream: "BATCH_END:timestamp"
+            output_stream: "ITERABLE:ints_plus_one"
+          }
+        )");
+    tool::AddVectorSink("ints_plus_one", &graph_config, &output_packets_);
+    MP_ASSERT_OK(graph_.Initialize(graph_config));
+    MP_ASSERT_OK(graph_.StartRun({}));
+  }
+
+  void SendPacketOfInts(Timestamp timestamp, std::vector<int> ints) {
+    MP_ASSERT_OK(graph_.AddPacketToInputStream(
+        "ints", MakePacket<std::vector<int>>(std::move(ints)).At(timestamp)));
+  }
+
+  CalculatorGraph graph_;
+  std::vector<Packet> output_packets_;
+};
+
+TEST_F(BeginEndLoopCalculatorGraphTest, InputStreamForIterableIsEmpty) {
+  MP_ASSERT_OK(graph_.WaitUntilIdle());
+
+  // EndLoopCalc will forward the timestamp bound because there are no packets
+  // to process.
+  ASSERT_EQ(0, output_packets_.size());
+
+  MP_ASSERT_OK(graph_.CloseAllPacketSources());
+  MP_ASSERT_OK(graph_.WaitUntilDone());
+}
+
+TEST_F(BeginEndLoopCalculatorGraphTest, SingleEmptyVector) {
+  SendPacketOfInts(Timestamp(0), {});
+  MP_ASSERT_OK(graph_.WaitUntilIdle());
+
+  // EndLoopCalc will forward the timestamp bound because there are no elements
+  // in collection to output.
+  EXPECT_TRUE(output_packets_.empty());
+
+  MP_ASSERT_OK(graph_.CloseAllPacketSources());
+  MP_ASSERT_OK(graph_.WaitUntilDone());
+}
+
+TEST_F(BeginEndLoopCalculatorGraphTest, SingleNonEmptyVector) {
+  Timestamp input_timestamp = Timestamp(0);
+  SendPacketOfInts(input_timestamp, {0, 1, 2});
+  MP_ASSERT_OK(graph_.WaitUntilIdle());
+
+  EXPECT_THAT(output_packets_,
+              testing::ElementsAre(
+                  PacketOfIntsEq(input_timestamp, std::vector<int>{1, 2, 3})));
+
+  MP_ASSERT_OK(graph_.CloseAllPacketSources());
+  MP_ASSERT_OK(graph_.WaitUntilDone());
+}
+
+TEST_F(BeginEndLoopCalculatorGraphTest, MultipleVectors) {
+  Timestamp input_timestamp0 = Timestamp(0);
+  SendPacketOfInts(input_timestamp0, {0, 1});
+
+  Timestamp input_timestamp1 = Timestamp(1);
+  SendPacketOfInts(input_timestamp1, {});
+
+  Timestamp input_timestamp2 = Timestamp(2);
+  SendPacketOfInts(input_timestamp2, {2, 3});
+
+  MP_ASSERT_OK(graph_.CloseAllPacketSources());
+  MP_ASSERT_OK(graph_.WaitUntilDone());
+
+  // At input_timestamp1, EndLoopCalc will forward timestamp bound as there are
+  // no elements in vector to process.
+  EXPECT_THAT(output_packets_,
+              testing::ElementsAre(
+                  PacketOfIntsEq(input_timestamp0, std::vector<int>{1, 2}),
+                  PacketOfIntsEq(input_timestamp2, std::vector<int>{3, 4})));
+}
+
+// Passes non empty vector through or outputs empty vector in case of timestamp
+// bound update.
+class PassThroughOrEmptyVectorCalculator : public CalculatorBase {
+ public:
+  static ::mediapipe::Status GetContract(CalculatorContract* cc) {
+    cc->SetProcessTimestampBounds(true);
+    cc->Inputs().Index(0).Set<std::vector<int>>();
+    cc->Outputs().Index(0).Set<std::vector<int>>();
+    return ::mediapipe::OkStatus();
+  }
+
+  ::mediapipe::Status Open(CalculatorContext* cc) override {
+    cc->SetOffset(TimestampDiff(0));
+    return ::mediapipe::OkStatus();
+  }
+
+  ::mediapipe::Status Process(CalculatorContext* cc) override {
+    if (!cc->Inputs().Index(0).IsEmpty()) {
+      cc->Outputs().Index(0).AddPacket(cc->Inputs().Index(0).Value());
+    } else {
+      cc->Outputs().Index(0).AddPacket(
+          MakePacket<std::vector<int>>(std::vector<int>())
+              .At(cc->InputTimestamp()));
+    }
+    return ::mediapipe::OkStatus();
+  }
+};
+
+REGISTER_CALCULATOR(PassThroughOrEmptyVectorCalculator);
+
+class BeginEndLoopCalculatorGraphProcessingEmptyPacketsTest
+    : public ::testing::Test {
+ protected:
+  void SetUp() override {
+    auto graph_config = ParseTextProtoOrDie<CalculatorGraphConfig>(
+        R"(
+          num_threads: 4
+          input_stream: "ints"
+          input_stream: "force_ints_to_be_timestamp_bound_update"
+          node {
+            calculator: "GateCalculator"
+            input_stream: "ints"
+            input_stream: "DISALLOW:force_ints_to_be_timestamp_bound_update"
+            output_stream: "ints_passed_through"
+          }
+          node {
+            calculator: "BeginLoopIntegerCalculator"
+            input_stream: "ITERABLE:ints_passed_through"
+            output_stream: "ITEM:int"
+            output_stream: "BATCH_END:timestamp"
+          }
+          node {
+            calculator: "IncrementCalculator"
+            input_stream: "int"
+            output_stream: "int_plus_one"
+          }
+          node {
+            calculator: "EndLoopIntegersCalculator"
+            input_stream: "ITEM:int_plus_one"
+            input_stream: "BATCH_END:timestamp"
+            output_stream: "ITERABLE:ints_plus_one"
+          }
+          node {
+            calculator: "PassThroughOrEmptyVectorCalculator"
+            input_stream: "ints_plus_one"
+            output_stream: "ints_plus_one_passed_through"
+          }
+        )");
+    tool::AddVectorSink("ints_plus_one_passed_through", &graph_config,
+                        &output_packets_);
+    MP_ASSERT_OK(graph_.Initialize(graph_config));
+    MP_ASSERT_OK(graph_.StartRun({}));
+  }
+
+  void SendPacketOfIntsOrBound(Timestamp timestamp, std::vector<int> ints) {
+    // All "ints" packets which are empty are forced to be just timestamp
+    // bound updates for begin loop calculator.
+    bool force_ints_to_be_timestamp_bound_update = ints.empty();
+    MP_ASSERT_OK(graph_.AddPacketToInputStream(
+        "force_ints_to_be_timestamp_bound_update",
+        MakePacket<bool>(force_ints_to_be_timestamp_bound_update)
+            .At(timestamp)));
+    MP_ASSERT_OK(graph_.AddPacketToInputStream(
+        "ints", MakePacket<std::vector<int>>(std::move(ints)).At(timestamp)));
+  }
+
+  CalculatorGraph graph_;
+  std::vector<Packet> output_packets_;
+};
+
+TEST_F(BeginEndLoopCalculatorGraphProcessingEmptyPacketsTest,
+       SingleEmptyVector) {
+  SendPacketOfIntsOrBound(Timestamp(0), {});
+  MP_ASSERT_OK(graph_.WaitUntilIdle());
+
+  EXPECT_THAT(output_packets_, testing::ElementsAre(PacketOfIntsEq(
+                                   Timestamp(0), std::vector<int>{})));
+
+  MP_ASSERT_OK(graph_.CloseAllPacketSources());
+  MP_ASSERT_OK(graph_.WaitUntilDone());
+}
+
+TEST_F(BeginEndLoopCalculatorGraphProcessingEmptyPacketsTest,
+       SingleNonEmptyVector) {
+  SendPacketOfIntsOrBound(Timestamp(0), {0, 1, 2});
+  MP_ASSERT_OK(graph_.WaitUntilIdle());
+
+  EXPECT_THAT(output_packets_, testing::ElementsAre(PacketOfIntsEq(
+                                   Timestamp(0), std::vector<int>{1, 2, 3})));
+
+  MP_ASSERT_OK(graph_.CloseAllPacketSources());
+  MP_ASSERT_OK(graph_.WaitUntilDone());
+}
+
+TEST_F(BeginEndLoopCalculatorGraphProcessingEmptyPacketsTest, MultipleVectors) {
+  SendPacketOfIntsOrBound(Timestamp(0), {});
+  // Waiting until idle to guarantee all timestamp bound updates are processed
+  // individually. (Timestamp bounds updates occur in the provide config only
+  // if input is an empty vector.)
+  MP_ASSERT_OK(graph_.WaitUntilIdle());
+
+  SendPacketOfIntsOrBound(Timestamp(1), {0, 1});
+  SendPacketOfIntsOrBound(Timestamp(2), {});
+  // Waiting until idle to guarantee all timestamp bound updates are processed
+  // individually. (Timestamp bounds updates occur in the provide config only
+  // if input is an empty vector.)
+  MP_ASSERT_OK(graph_.WaitUntilIdle());
+
+  SendPacketOfIntsOrBound(Timestamp(3), {2, 3});
+  SendPacketOfIntsOrBound(Timestamp(4), {});
+  // Waiting until idle to guarantee all timestamp bound updates are processed
+  // individually. (Timestamp bounds updates occur in the provide config only
+  // if input is an empty vector.)
+  MP_ASSERT_OK(graph_.WaitUntilIdle());
+
+  MP_ASSERT_OK(graph_.CloseAllPacketSources());
+  MP_ASSERT_OK(graph_.WaitUntilDone());
+
+  EXPECT_THAT(
+      output_packets_,
+      testing::ElementsAre(PacketOfIntsEq(Timestamp(0), std::vector<int>{}),
+                           PacketOfIntsEq(Timestamp(1), std::vector<int>{1, 2}),
+                           PacketOfIntsEq(Timestamp(2), std::vector<int>{}),
+                           PacketOfIntsEq(Timestamp(3), std::vector<int>{3, 4}),
+                           PacketOfIntsEq(Timestamp(4), std::vector<int>{})));
+}
+
+class MultiplierCalculator : public CalculatorBase {
+ public:
+  static ::mediapipe::Status GetContract(CalculatorContract* cc) {
+    cc->Inputs().Index(0).Set<int>();
+    cc->Inputs().Index(1).Set<int>();
+    cc->Outputs().Index(0).Set<int>();
+    return ::mediapipe::OkStatus();
+  }
+
+  ::mediapipe::Status Open(CalculatorContext* cc) override {
+    cc->SetOffset(TimestampDiff(0));
+    return ::mediapipe::OkStatus();
+  }
+
+  ::mediapipe::Status Process(CalculatorContext* cc) override {
+    const int& input_int = cc->Inputs().Index(0).Get<int>();
+    const int& multiplier_int = cc->Inputs().Index(1).Get<int>();
+    auto output_int = absl::make_unique<int>(input_int * multiplier_int);
+    cc->Outputs().Index(0).Add(output_int.release(), cc->InputTimestamp());
+    return ::mediapipe::OkStatus();
+  }
+};
+
+REGISTER_CALCULATOR(MultiplierCalculator);
+
+class BeginEndLoopCalculatorGraphWithClonedInputsTest : public ::testing::Test {
+ protected:
+  void SetUp() override {
+    auto graph_config = ParseTextProtoOrDie<CalculatorGraphConfig>(
+        R"(
+          num_threads: 4
+          input_stream: "ints"
+          input_stream: "multiplier"
+          node {
+            calculator: "BeginLoopIntegerCalculator"
+            input_stream: "ITERABLE:ints"
+            input_stream: "CLONE:multiplier"
+            output_stream: "ITEM:int_at_loop"
+            output_stream: "CLONE:multiplier_cloned_at_loop"
+            output_stream: "BATCH_END:timestamp"
+          }
+          node {
+            calculator: "MultiplierCalculator"
+            input_stream: "int_at_loop"
+            input_stream: "multiplier_cloned_at_loop"
+            output_stream: "multiplied_int_at_loop"
+          }
+          node {
+            calculator: "EndLoopIntegersCalculator"
+            input_stream: "ITEM:multiplied_int_at_loop"
+            input_stream: "BATCH_END:timestamp"
+            output_stream: "ITERABLE:multiplied_ints"
+          }
+        )");
+    tool::AddVectorSink("multiplied_ints", &graph_config, &output_packets_);
+    MP_ASSERT_OK(graph_.Initialize(graph_config));
+    MP_ASSERT_OK(graph_.StartRun({}));
+  }
+
+  void SendPackets(Timestamp timestamp, int multiplier, std::vector<int> ints) {
+    MP_ASSERT_OK(graph_.AddPacketToInputStream(
+        "ints", MakePacket<std::vector<int>>(std::move(ints)).At(timestamp)));
+    MP_ASSERT_OK(graph_.AddPacketToInputStream(
+        "multiplier", MakePacket<int>(multiplier).At(timestamp)));
+  }
+
+  void SendMultiplier(Timestamp timestamp, int multiplier) {
+    MP_ASSERT_OK(graph_.AddPacketToInputStream(
+        "multiplier", MakePacket<int>(multiplier).At(timestamp)));
+  }
+
+  CalculatorGraph graph_;
+  std::vector<Packet> output_packets_;
+};
+
+TEST_F(BeginEndLoopCalculatorGraphWithClonedInputsTest,
+       InputStreamForIterableIsEmpty) {
+  Timestamp input_timestamp = Timestamp(42);
+  SendMultiplier(input_timestamp, /*multiplier=*/2);
+  MP_ASSERT_OK(graph_.WaitUntilIdle());
+
+  // EndLoopCalc will forward the timestamp bound because there are no packets
+  // to process.
+  ASSERT_EQ(0, output_packets_.size());
+
+  MP_ASSERT_OK(graph_.CloseAllPacketSources());
+  MP_ASSERT_OK(graph_.WaitUntilDone());
+}
+
+TEST_F(BeginEndLoopCalculatorGraphWithClonedInputsTest, SingleEmptyVector) {
+  SendPackets(Timestamp(0), /*multiplier=*/2, /*ints=*/{});
+  MP_ASSERT_OK(graph_.WaitUntilIdle());
+
+  // EndLoopCalc will forward the timestamp bound because there are no elements
+  // in collection to output.
+  EXPECT_TRUE(output_packets_.empty());
+
+  MP_ASSERT_OK(graph_.CloseAllPacketSources());
+  MP_ASSERT_OK(graph_.WaitUntilDone());
+}
+
+TEST_F(BeginEndLoopCalculatorGraphWithClonedInputsTest, SingleNonEmptyVector) {
+  Timestamp input_timestamp = Timestamp(42);
+  SendPackets(input_timestamp, /*multiplier=*/2, /*ints=*/{0, 1, 2});
+  MP_ASSERT_OK(graph_.WaitUntilIdle());
+
+  EXPECT_THAT(output_packets_,
+              testing::ElementsAre(
+                  PacketOfIntsEq(input_timestamp, std::vector<int>{0, 2, 4})));
+
+  MP_ASSERT_OK(graph_.CloseAllPacketSources());
+  MP_ASSERT_OK(graph_.WaitUntilDone());
+}
+
+TEST_F(BeginEndLoopCalculatorGraphWithClonedInputsTest, MultipleVectors) {
+  Timestamp input_timestamp0 = Timestamp(42);
+  SendPackets(input_timestamp0, /*multiplier=*/2, /*ints=*/{0, 1});
+
+  Timestamp input_timestamp1 = Timestamp(43);
+  SendPackets(input_timestamp1, /*multiplier=*/2, /*ints=*/{});
+
+  Timestamp input_timestamp2 = Timestamp(44);
+  SendPackets(input_timestamp2, /*multiplier=*/3, /*ints=*/{2, 3});
+
+  MP_ASSERT_OK(graph_.CloseAllPacketSources());
+  MP_ASSERT_OK(graph_.WaitUntilDone());
+
+  // At input_timestamp1, EndLoopCalc will forward timestamp bound as there are
+  // no elements in vector to process.
+  EXPECT_THAT(output_packets_,
+              testing::ElementsAre(
+                  PacketOfIntsEq(input_timestamp0, std::vector<int>{0, 2}),
+                  PacketOfIntsEq(input_timestamp2, std::vector<int>{6, 9})));
+}
+
+}  // namespace
+}  // namespace mediapipe
@@ -0,0 +1,45 @@
+// Copyright 2019 The MediaPipe Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "mediapipe/calculators/core/begin_loop_calculator.h"
+
+#include <vector>
+
+#include "mediapipe/framework/formats/detection.pb.h"
+#include "mediapipe/framework/formats/landmark.pb.h"
+#include "mediapipe/framework/formats/matrix.h"
+#include "mediapipe/framework/formats/rect.pb.h"
+
+namespace mediapipe {
+
+// A calculator to process std::vector<NormalizedLandmarkList>.
+typedef BeginLoopCalculator<std::vector<::mediapipe::NormalizedLandmarkList>>
+    BeginLoopNormalizedLandmarkListVectorCalculator;
+REGISTER_CALCULATOR(BeginLoopNormalizedLandmarkListVectorCalculator);
+
+// A calculator to process std::vector<NormalizedRect>.
+typedef BeginLoopCalculator<std::vector<::mediapipe::NormalizedRect>>
+    BeginLoopNormalizedRectCalculator;
+REGISTER_CALCULATOR(BeginLoopNormalizedRectCalculator);
+
+// A calculator to process std::vector<Detection>.
+typedef BeginLoopCalculator<std::vector<::mediapipe::Detection>>
+    BeginLoopDetectionCalculator;
+REGISTER_CALCULATOR(BeginLoopDetectionCalculator);
+
+// A calculator to process std::vector<Matrix>.
+typedef BeginLoopCalculator<std::vector<Matrix>> BeginLoopMatrixCalculator;
+REGISTER_CALCULATOR(BeginLoopMatrixCalculator);
+
+}  // namespace mediapipe
@@ -0,0 +1,165 @@
+// Copyright 2019 The MediaPipe Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef MEDIAPIPE_CALCULATORS_CORE_BEGIN_LOOP_CALCULATOR_H_
+#define MEDIAPIPE_CALCULATORS_CORE_BEGIN_LOOP_CALCULATOR_H_
+
+#include "absl/memory/memory.h"
+#include "mediapipe/framework/calculator_context.h"
+#include "mediapipe/framework/calculator_contract.h"
+#include "mediapipe/framework/calculator_framework.h"
+#include "mediapipe/framework/collection_item_id.h"
+#include "mediapipe/framework/packet.h"
+#include "mediapipe/framework/port/integral_types.h"
+#include "mediapipe/framework/port/ret_check.h"
+#include "mediapipe/framework/port/status.h"
+
+namespace mediapipe {
+
+// Calculator for implementing loops on iterable collections inside a MediaPipe
+// graph.
+//
+// It is designed to be used like:
+//
+// node {
+//   calculator:    "BeginLoopWithIterableCalculator"
+//   input_stream:  "ITERABLE:input_iterable"      # IterableT @ext_ts
+//   output_stream: "ITEM:input_element"           # ItemT     @loop_internal_ts
+//   output_stream: "BATCH_END:ext_ts"             # Timestamp @loop_internal_ts
+// }
+//
+// node {
+//   calculator:    "ElementToBlaConverterSubgraph"
+//   input_stream:  "ITEM:input_to_loop_body"      # ItemT     @loop_internal_ts
+//   output_stream: "BLA:output_of_loop_body"      # ItemU     @loop_internal_ts
+// }
+//
+// node {
+//   calculator:    "EndLoopWithOutputCalculator"
+//   input_stream:  "ITEM:output_of_loop_body"     # ItemU     @loop_internal_ts
+//   input_stream:  "BATCH_END:ext_ts"             # Timestamp @loop_internal_ts
+//   output_stream: "OUTPUT:aggregated_result"     # IterableU @ext_ts
+// }
+//
+// Input streams tagged with "CLONE" are cloned to the corresponding output
+// streams at loop timestamps. This ensures that a MediaPipe graph or sub-graph
+// can run multiple times, once per element in the "ITERABLE" for each pakcet
+// clone of the packets in the "CLONE" input streams.
+template <typename IterableT>
+class BeginLoopCalculator : public CalculatorBase {
+  using ItemT = typename IterableT::value_type;
+
+ public:
+  static ::mediapipe::Status GetContract(CalculatorContract* cc) {
+    // The below enables processing of timestamp bound updates, and that enables
+    // correct timestamp propagation by the companion EndLoopCalculator.
+    //
+    // For instance, Process() function will be still invoked even if upstream
+    // calculator has updated timestamp bound for ITERABLE input instead of
+    // providing actual value.
+    cc->SetProcessTimestampBounds(true);
+
+    // A non-empty packet in the optional "TICK" input stream wakes up the
+    // calculator.
+    // DEPRECATED as timestamp bound updates are processed by default in this
+    // calculator.
+    if (cc->Inputs().HasTag("TICK")) {
+      cc->Inputs().Tag("TICK").SetAny();
+    }
+
+    // An iterable collection in the input stream.
+    RET_CHECK(cc->Inputs().HasTag("ITERABLE"));
+    cc->Inputs().Tag("ITERABLE").Set<IterableT>();
+
+    // An element from the collection.
+    RET_CHECK(cc->Outputs().HasTag("ITEM"));
+    cc->Outputs().Tag("ITEM").Set<ItemT>();
+
+    RET_CHECK(cc->Outputs().HasTag("BATCH_END"));
+    cc->Outputs()
+        .Tag("BATCH_END")
+        .Set<Timestamp>(
+            // A flush signal to the corresponding EndLoopCalculator for it to
+            // emit the aggregated result with the timestamp contained in this
+            // flush signal packet.
+        );
+
+    // Input streams tagged with "CLONE" are cloned to the corresponding
+    // "CLONE" output streams at loop timestamps.
+    RET_CHECK(cc->Inputs().NumEntries("CLONE") ==
+              cc->Outputs().NumEntries("CLONE"));
+    if (cc->Inputs().NumEntries("CLONE") > 0) {
+      for (int i = 0; i < cc->Inputs().NumEntries("CLONE"); ++i) {
+        cc->Inputs().Get("CLONE", i).SetAny();
+        cc->Outputs().Get("CLONE", i).SetSameAs(&cc->Inputs().Get("CLONE", i));
+      }
+    }
+
+    return ::mediapipe::OkStatus();
+  }
+
+  ::mediapipe::Status Process(CalculatorContext* cc) final {
+    Timestamp last_timestamp = loop_internal_timestamp_;
+    if (!cc->Inputs().Tag("ITERABLE").IsEmpty()) {
+      const IterableT& collection =
+          cc->Inputs().Tag("ITERABLE").template Get<IterableT>();
+      for (const auto& item : collection) {
+        cc->Outputs().Tag("ITEM").AddPacket(
+            MakePacket<ItemT>(item).At(loop_internal_timestamp_));
+        ForwardClonePackets(cc, loop_internal_timestamp_);
+        ++loop_internal_timestamp_;
+      }
+    }
+
+    // The collection was empty and nothing was processed.
+    if (last_timestamp == loop_internal_timestamp_) {
+      // Increment loop_internal_timestamp_ because it is used up now.
+      ++loop_internal_timestamp_;
+      for (auto it = cc->Outputs().begin(); it < cc->Outputs().end(); ++it) {
+        it->SetNextTimestampBound(loop_internal_timestamp_);
+      }
+    }
+
+    // The for loop processing the input collection already incremented
+    // loop_internal_timestamp_. To emit BATCH_END packet along the last
+    // non-BATCH_END packet, decrement by one.
+    cc->Outputs()
+        .Tag("BATCH_END")
+        .AddPacket(MakePacket<Timestamp>(cc->InputTimestamp())
+                       .At(Timestamp(loop_internal_timestamp_ - 1)));
+
+    return ::mediapipe::OkStatus();
+  }
+
+ private:
+  void ForwardClonePackets(CalculatorContext* cc, Timestamp output_timestamp) {
+    if (cc->Inputs().NumEntries("CLONE") > 0) {
+      for (int i = 0; i < cc->Inputs().NumEntries("CLONE"); ++i) {
+        if (!cc->Inputs().Get("CLONE", i).IsEmpty()) {
+          auto input_packet = cc->Inputs().Get("CLONE", i).Value();
+          cc->Outputs()
+              .Get("CLONE", i)
+              .AddPacket(std::move(input_packet).At(output_timestamp));
+        }
+      }
+    }
+  }
+
+  // Fake timestamps generated per element in collection.
+  Timestamp loop_internal_timestamp_ = Timestamp(0);
+};
+
+}  // namespace mediapipe
+
+#endif  // MEDIAPIPE_CALCULATORS_CORE_BEGIN_LOOP_CALCULATOR_H_
@@ -0,0 +1,26 @@
+// Copyright 2019 The MediaPipe Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include <vector>
+
+#include "mediapipe/calculators/core/clip_vector_size_calculator.h"
+#include "mediapipe/framework/formats/detection.pb.h"
+
+namespace mediapipe {
+
+typedef ClipVectorSizeCalculator<::mediapipe::Detection>
+    ClipDetectionVectorSizeCalculator;
+REGISTER_CALCULATOR(ClipDetectionVectorSizeCalculator);
+
+}  // namespace mediapipe
@@ -0,0 +1,33 @@
+// Copyright 2019 The MediaPipe Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "mediapipe/calculators/core/clip_vector_size_calculator.h"
+
+#include <vector>
+
+#include "mediapipe/framework/calculator_framework.h"
+#include "mediapipe/framework/formats/detection.pb.h"
+#include "mediapipe/framework/formats/rect.pb.h"
+
+namespace mediapipe {
+
+typedef ClipVectorSizeCalculator<::mediapipe::NormalizedRect>
+    ClipNormalizedRectVectorSizeCalculator;
+REGISTER_CALCULATOR(ClipNormalizedRectVectorSizeCalculator);
+
+typedef ClipVectorSizeCalculator<::mediapipe::Detection>
+    ClipDetectionVectorSizeCalculator;
+REGISTER_CALCULATOR(ClipDetectionVectorSizeCalculator);
+
+}  // namespace mediapipe
@@ -0,0 +1,148 @@
+// Copyright 2019 The MediaPipe Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef MEDIAPIPE_CALCULATORS_CORE_CLIP_VECTOR_SIZE_CALCULATOR_H_
+#define MEDIAPIPE_CALCULATORS_CORE_CLIP_VECTOR_SIZE_CALCULATOR_H_
+
+#include <type_traits>
+#include <vector>
+
+#include "mediapipe/calculators/core/clip_vector_size_calculator.pb.h"
+#include "mediapipe/framework/calculator_framework.h"
+#include "mediapipe/framework/port/canonical_errors.h"
+#include "mediapipe/framework/port/ret_check.h"
+#include "mediapipe/framework/port/status.h"
+
+namespace mediapipe {
+
+// Clips the size of the input vector of type T to a specified max_vec_size.
+// In a graph it will be used as:
+// node {
+//   calculator: "ClipIntVectorSizeCalculator"
+//   input_stream: "input_vector"
+//   output_stream: "output_vector"
+//   options {
+//     [mediapipe.ClipIntVectorSizeCalculatorOptions.ext] {
+//       max_vec_size: 5
+//     }
+//   }
+// }
+// Optionally, you can pass in a side packet that will override `max_vec_size`
+// that is specified in the options.
+template <typename T>
+class ClipVectorSizeCalculator : public CalculatorBase {
+ public:
+  static ::mediapipe::Status GetContract(CalculatorContract* cc) {
+    RET_CHECK(cc->Inputs().NumEntries() == 1);
+    RET_CHECK(cc->Outputs().NumEntries() == 1);
+
+    if (cc->Options<::mediapipe::ClipVectorSizeCalculatorOptions>()
+            .max_vec_size() < 1) {
+      return ::mediapipe::InternalError(
+          "max_vec_size should be greater than or equal to 1.");
+    }
+
+    cc->Inputs().Index(0).Set<std::vector<T>>();
+    cc->Outputs().Index(0).Set<std::vector<T>>();
+    // Optional input side packet that determines `max_vec_size`.
+    if (cc->InputSidePackets().NumEntries() > 0) {
+      cc->InputSidePackets().Index(0).Set<int>();
+    }
+
+    return ::mediapipe::OkStatus();
+  }
+
+  ::mediapipe::Status Open(CalculatorContext* cc) override {
+    cc->SetOffset(TimestampDiff(0));
+    max_vec_size_ = cc->Options<::mediapipe::ClipVectorSizeCalculatorOptions>()
+                        .max_vec_size();
+    // Override `max_vec_size` if passed as side packet.
+    if (cc->InputSidePackets().NumEntries() > 0 &&
+        !cc->InputSidePackets().Index(0).IsEmpty()) {
+      max_vec_size_ = cc->InputSidePackets().Index(0).Get<int>();
+    }
+    return ::mediapipe::OkStatus();
+  }
+
+  ::mediapipe::Status Process(CalculatorContext* cc) override {
+    if (max_vec_size_ < 1) {
+      return ::mediapipe::InternalError(
+          "max_vec_size should be greater than or equal to 1.");
+    }
+    if (cc->Inputs().Index(0).IsEmpty()) {
+      return ::mediapipe::OkStatus();
+    }
+
+    return ClipVectorSize<T>(std::is_copy_constructible<T>(), cc);
+  }
+
+  template <typename U>
+  ::mediapipe::Status ClipVectorSize(std::true_type, CalculatorContext* cc) {
+    auto output = absl::make_unique<std::vector<U>>();
+    const std::vector<U>& input_vector =
+        cc->Inputs().Index(0).Get<std::vector<U>>();
+    if (max_vec_size_ >= input_vector.size()) {
+      output->insert(output->end(), input_vector.begin(), input_vector.end());
+    } else {
+      for (int i = 0; i < max_vec_size_; ++i) {
+        output->push_back(input_vector[i]);
+      }
+    }
+    cc->Outputs().Index(0).Add(output.release(), cc->InputTimestamp());
+    return ::mediapipe::OkStatus();
+  }
+
+  template <typename U>
+  ::mediapipe::Status ClipVectorSize(std::false_type, CalculatorContext* cc) {
+    return ConsumeAndClipVectorSize<T>(std::is_move_constructible<U>(), cc);
+  }
+
+  template <typename U>
+  ::mediapipe::Status ConsumeAndClipVectorSize(std::true_type,
+                                               CalculatorContext* cc) {
+    auto output = absl::make_unique<std::vector<U>>();
+    ::mediapipe::StatusOr<std::unique_ptr<std::vector<U>>> input_status =
+        cc->Inputs().Index(0).Value().Consume<std::vector<U>>();
+
+    if (input_status.ok()) {
+      std::unique_ptr<std::vector<U>> input_vector =
+          std::move(input_status).ValueOrDie();
+      auto begin_it = input_vector->begin();
+      auto end_it = input_vector->end();
+      if (max_vec_size_ < input_vector->size()) {
+        end_it = input_vector->begin() + max_vec_size_;
+      }
+      output->insert(output->end(), std::make_move_iterator(begin_it),
+                     std::make_move_iterator(end_it));
+    } else {
+      return input_status.status();
+    }
+    cc->Outputs().Index(0).Add(output.release(), cc->InputTimestamp());
+    return ::mediapipe::OkStatus();
+  }
+
+  template <typename U>
+  ::mediapipe::Status ConsumeAndClipVectorSize(std::false_type,
+                                               CalculatorContext* cc) {
+    return ::mediapipe::InternalError(
+        "Cannot copy or move input vectors and clip their size.");
+  }
+
+ private:
+  int max_vec_size_ = 0;
+};
+
+}  // namespace mediapipe
+
+#endif  // MEDIAPIPE_CALCULATORS_CORE_CLIP_VECTOR_SIZE_CALCULATOR_H_
@@ -0,0 +1,28 @@
+// Copyright 2019 The MediaPipe Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+syntax = "proto2";
+
+package mediapipe;
+
+import "mediapipe/framework/calculator.proto";
+
+message ClipVectorSizeCalculatorOptions {
+  extend CalculatorOptions {
+    optional ClipVectorSizeCalculatorOptions ext = 274674998;
+  }
+
+  // Maximum size of output vector.
+  optional int32 max_vec_size = 1 [default = 1];
+}
@@ -0,0 +1,206 @@
+// Copyright 2019 The MediaPipe Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "mediapipe/calculators/core/clip_vector_size_calculator.h"
+
+#include <memory>
+#include <string>
+#include <vector>
+
+#include "mediapipe/framework/calculator_framework.h"
+#include "mediapipe/framework/calculator_runner.h"
+#include "mediapipe/framework/port/gmock.h"
+#include "mediapipe/framework/port/gtest.h"
+#include "mediapipe/framework/port/parse_text_proto.h"
+#include "mediapipe/framework/port/status_matchers.h"  // NOLINT
+
+namespace mediapipe {
+
+typedef ClipVectorSizeCalculator<int> TestClipIntVectorSizeCalculator;
+REGISTER_CALCULATOR(TestClipIntVectorSizeCalculator);
+
+void AddInputVector(const std::vector<int>& input, int64 timestamp,
+                    CalculatorRunner* runner) {
+  runner->MutableInputs()->Index(0).packets.push_back(
+      MakePacket<std::vector<int>>(input).At(Timestamp(timestamp)));
+}
+
+TEST(TestClipIntVectorSizeCalculatorTest, EmptyVectorInput) {
+  CalculatorGraphConfig::Node node_config =
+      ParseTextProtoOrDie<CalculatorGraphConfig::Node>(R"(
+        calculator: "TestClipIntVectorSizeCalculator"
+        input_stream: "input_vector"
+        output_stream: "output_vector"
+        options {
+          [mediapipe.ClipVectorSizeCalculatorOptions.ext] { max_vec_size: 1 }
+        }
+      )");
+  CalculatorRunner runner(node_config);
+
+  std::vector<int> input = {};
+  AddInputVector(input, /*timestamp=*/1, &runner);
+  MP_ASSERT_OK(runner.Run());
+
+  const std::vector<Packet>& outputs = runner.Outputs().Index(0).packets;
+  EXPECT_EQ(1, outputs.size());
+  EXPECT_EQ(Timestamp(1), outputs[0].Timestamp());
+  EXPECT_TRUE(outputs[0].Get<std::vector<int>>().empty());
+}
+
+TEST(TestClipIntVectorSizeCalculatorTest, OneTimestamp) {
+  CalculatorGraphConfig::Node node_config =
+      ParseTextProtoOrDie<CalculatorGraphConfig::Node>(R"(
+        calculator: "TestClipIntVectorSizeCalculator"
+        input_stream: "input_vector"
+        output_stream: "output_vector"
+        options {
+          [mediapipe.ClipVectorSizeCalculatorOptions.ext] { max_vec_size: 2 }
+        }
+      )");
+  CalculatorRunner runner(node_config);
+
+  std::vector<int> input = {0, 1, 2, 3};
+  AddInputVector(input, /*timestamp=*/1, &runner);
+  MP_ASSERT_OK(runner.Run());
+
+  const std::vector<Packet>& outputs = runner.Outputs().Index(0).packets;
+  EXPECT_EQ(1, outputs.size());
+  EXPECT_EQ(Timestamp(1), outputs[0].Timestamp());
+  const std::vector<int>& output = outputs[0].Get<std::vector<int>>();
+  EXPECT_EQ(2, output.size());
+  std::vector<int> expected_vector = {0, 1};
+  EXPECT_EQ(expected_vector, output);
+}
+
+TEST(TestClipIntVectorSizeCalculatorTest, TwoInputsAtTwoTimestamps) {
+  CalculatorGraphConfig::Node node_config =
+      ParseTextProtoOrDie<CalculatorGraphConfig::Node>(R"(
+        calculator: "TestClipIntVectorSizeCalculator"
+        input_stream: "input_vector"
+        output_stream: "output_vector"
+        options {
+          [mediapipe.ClipVectorSizeCalculatorOptions.ext] { max_vec_size: 3 }
+        }
+      )");
+  CalculatorRunner runner(node_config);
+
+  {
+    std::vector<int> input = {0, 1, 2, 3};
+    AddInputVector(input, /*timestamp=*/1, &runner);
+  }
+  {
+    std::vector<int> input = {2, 3, 4, 5};
+    AddInputVector(input, /*timestamp=*/2, &runner);
+  }
+  MP_ASSERT_OK(runner.Run());
+
+  const std::vector<Packet>& outputs = runner.Outputs().Index(0).packets;
+  EXPECT_EQ(2, outputs.size());
+  {
+    EXPECT_EQ(Timestamp(1), outputs[0].Timestamp());
+    const std::vector<int>& output = outputs[0].Get<std::vector<int>>();
+    EXPECT_EQ(3, output.size());
+    std::vector<int> expected_vector = {0, 1, 2};
+    EXPECT_EQ(expected_vector, output);
+  }
+  {
+    EXPECT_EQ(Timestamp(2), outputs[1].Timestamp());
+    const std::vector<int>& output = outputs[1].Get<std::vector<int>>();
+    EXPECT_EQ(3, output.size());
+    std::vector<int> expected_vector = {2, 3, 4};
+    EXPECT_EQ(expected_vector, output);
+  }
+}
+
+typedef ClipVectorSizeCalculator<std::unique_ptr<int>>
+    TestClipUniqueIntPtrVectorSizeCalculator;
+REGISTER_CALCULATOR(TestClipUniqueIntPtrVectorSizeCalculator);
+
+TEST(TestClipUniqueIntPtrVectorSizeCalculatorTest, ConsumeOneTimestamp) {
+  /* Note: We don't use CalculatorRunner for this test because it keeps copies
+   * of input packets, so packets sent to the graph don't have sole ownership.
+   * The test needs to send packets that own the data.
+   */
+  CalculatorGraphConfig graph_config =
+      ParseTextProtoOrDie<CalculatorGraphConfig>(R"(
+        input_stream: "input_vector"
+        node {
+          calculator: "TestClipUniqueIntPtrVectorSizeCalculator"
+          input_stream: "input_vector"
+          output_stream: "output_vector"
+          options {
+            [mediapipe.ClipVectorSizeCalculatorOptions.ext] { max_vec_size: 3 }
+          }
+        }
+      )");
+
+  std::vector<Packet> outputs;
+  tool::AddVectorSink("output_vector", &graph_config, &outputs);
+
+  CalculatorGraph graph;
+  MP_EXPECT_OK(graph.Initialize(graph_config));
+  MP_EXPECT_OK(graph.StartRun({}));
+
+  // input1 : {0, 1, 2, 3, 4, 5}
+  auto input_vector = absl::make_unique<std::vector<std::unique_ptr<int>>>(6);
+  for (int i = 0; i < 6; ++i) {
+    input_vector->at(i) = absl::make_unique<int>(i);
+  }
+
+  MP_EXPECT_OK(graph.AddPacketToInputStream(
+      "input_vector", Adopt(input_vector.release()).At(Timestamp(1))));
+
+  MP_EXPECT_OK(graph.WaitUntilIdle());
+  MP_EXPECT_OK(graph.CloseAllPacketSources());
+  MP_EXPECT_OK(graph.WaitUntilDone());
+
+  EXPECT_EQ(1, outputs.size());
+  EXPECT_EQ(Timestamp(1), outputs[0].Timestamp());
+  const std::vector<std::unique_ptr<int>>& result =
+      outputs[0].Get<std::vector<std::unique_ptr<int>>>();
+  EXPECT_EQ(3, result.size());
+  for (int i = 0; i < 3; ++i) {
+    const std::unique_ptr<int>& v = result[i];
+    EXPECT_EQ(i, *v);
+  }
+}
+
+TEST(TestClipIntVectorSizeCalculatorTest, SidePacket) {
+  CalculatorGraphConfig::Node node_config =
+      ParseTextProtoOrDie<CalculatorGraphConfig::Node>(R"(
+        calculator: "TestClipIntVectorSizeCalculator"
+        input_stream: "input_vector"
+        input_side_packet: "max_vec_size"
+        output_stream: "output_vector"
+        options {
+          [mediapipe.ClipVectorSizeCalculatorOptions.ext] { max_vec_size: 1 }
+        }
+      )");
+  CalculatorRunner runner(node_config);
+  // This should override the default of 1 set in the options.
+  runner.MutableSidePackets()->Index(0) = Adopt(new int(2));
+  std::vector<int> input = {0, 1, 2, 3};
+  AddInputVector(input, /*timestamp=*/1, &runner);
+  MP_ASSERT_OK(runner.Run());
+
+  const std::vector<Packet>& outputs = runner.Outputs().Index(0).packets;
+  EXPECT_EQ(1, outputs.size());
+  EXPECT_EQ(Timestamp(1), outputs[0].Timestamp());
+  const std::vector<int>& output = outputs[0].Get<std::vector<int>>();
+  EXPECT_EQ(2, output.size());
+  std::vector<int> expected_vector = {0, 1};
+  EXPECT_EQ(expected_vector, output);
+}
+
+}  // namespace mediapipe
@@ -16,8 +16,13 @@

 #include <vector>

+#include "mediapipe/framework/formats/landmark.pb.h"
 #include "tensorflow/lite/interpreter.h"

+#if !defined(MEDIAPIPE_DISABLE_GL_COMPUTE)
+#include "tensorflow/lite/delegates/gpu/gl/gl_buffer.h"
+#endif  //  !MEDIAPIPE_DISABLE_GPU
+
 namespace mediapipe {

 // Example config:
@@ -30,6 +35,16 @@ namespace mediapipe {
 typedef ConcatenateVectorCalculator<float> ConcatenateFloatVectorCalculator;
 REGISTER_CALCULATOR(ConcatenateFloatVectorCalculator);

+// Example config:
+// node {
+//   calculator: "ConcatenateInt32VectorCalculator"
+//   input_stream: "int32_vector_1"
+//   input_stream: "int32_vector_2"
+//   output_stream: "concatenated_int32_vector"
+// }
+typedef ConcatenateVectorCalculator<int32> ConcatenateInt32VectorCalculator;
+REGISTER_CALCULATOR(ConcatenateInt32VectorCalculator);
+
 // Example config:
 // node {
 //   calculator: "ConcatenateTfLiteTensorVectorCalculator"
@@ -41,4 +56,14 @@ typedef ConcatenateVectorCalculator<TfLiteTensor>
    ConcatenateTfLiteTensorVectorCalculator;
 REGISTER_CALCULATOR(ConcatenateTfLiteTensorVectorCalculator);

+typedef ConcatenateVectorCalculator<::mediapipe::NormalizedLandmark>
+    ConcatenateLandmarkVectorCalculator;
+REGISTER_CALCULATOR(ConcatenateLandmarkVectorCalculator);
+
+#if !defined(MEDIAPIPE_DISABLE_GL_COMPUTE)
+typedef ConcatenateVectorCalculator<::tflite::gpu::gl::GlBuffer>
+    ConcatenateGlBufferVectorCalculator;
+REGISTER_CALCULATOR(ConcatenateGlBufferVectorCalculator);
+#endif
+
 }  // namespace mediapipe
@@ -15,6 +15,7 @@
 #ifndef MEDIAPIPE_CALCULATORS_CORE_CONCATENATE_VECTOR_CALCULATOR_H_
 #define MEDIAPIPE_CALCULATORS_CORE_CONCATENATE_VECTOR_CALCULATOR_H_

+#include <type_traits>
 #include <vector>

 #include "mediapipe/calculators/core/concatenate_vector_calculator.pb.h"
@@ -59,16 +60,58 @@ class ConcatenateVectorCalculator : public CalculatorBase {
        if (cc->Inputs().Index(i).IsEmpty()) return ::mediapipe::OkStatus();
      }
    }
-    auto output = absl::make_unique<std::vector<T>>();
+
+    return ConcatenateVectors<T>(std::is_copy_constructible<T>(), cc);
+  }
+
+  template <typename U>
+  ::mediapipe::Status ConcatenateVectors(std::true_type,
+                                         CalculatorContext* cc) {
+    auto output = absl::make_unique<std::vector<U>>();
    for (int i = 0; i < cc->Inputs().NumEntries(); ++i) {
      if (cc->Inputs().Index(i).IsEmpty()) continue;
-      const std::vector<T>& input = cc->Inputs().Index(i).Get<std::vector<T>>();
+      const std::vector<U>& input = cc->Inputs().Index(i).Get<std::vector<U>>();
      output->insert(output->end(), input.begin(), input.end());
    }
    cc->Outputs().Index(0).Add(output.release(), cc->InputTimestamp());
    return ::mediapipe::OkStatus();
  }

+  template <typename U>
+  ::mediapipe::Status ConcatenateVectors(std::false_type,
+                                         CalculatorContext* cc) {
+    return ConsumeAndConcatenateVectors<T>(std::is_move_constructible<U>(), cc);
+  }
+
+  template <typename U>
+  ::mediapipe::Status ConsumeAndConcatenateVectors(std::true_type,
+                                                   CalculatorContext* cc) {
+    auto output = absl::make_unique<std::vector<U>>();
+    for (int i = 0; i < cc->Inputs().NumEntries(); ++i) {
+      if (cc->Inputs().Index(i).IsEmpty()) continue;
+      ::mediapipe::StatusOr<std::unique_ptr<std::vector<U>>> input_status =
+          cc->Inputs().Index(i).Value().Consume<std::vector<U>>();
+      if (input_status.ok()) {
+        std::unique_ptr<std::vector<U>> input_vector =
+            std::move(input_status).ValueOrDie();
+        output->insert(output->end(),
+                       std::make_move_iterator(input_vector->begin()),
+                       std::make_move_iterator(input_vector->end()));
+      } else {
+        return input_status.status();
+      }
+    }
+    cc->Outputs().Index(0).Add(output.release(), cc->InputTimestamp());
+    return ::mediapipe::OkStatus();
+  }
+
+  template <typename U>
+  ::mediapipe::Status ConsumeAndConcatenateVectors(std::false_type,
+                                                   CalculatorContext* cc) {
+    return ::mediapipe::InternalError(
+        "Cannot copy or move input vectors to concatenate them");
+  }
+
 private:
  bool only_emit_if_all_present_;
 };
@@ -45,7 +45,7 @@ TEST(TestConcatenateIntVectorCalculatorTest, EmptyVectorInputs) {

  std::vector<std::vector<int>> inputs = {{}, {}, {}};
  AddInputVectors(inputs, /*timestamp=*/1, &runner);
-  MEDIAPIPE_ASSERT_OK(runner.Run());
+  MP_ASSERT_OK(runner.Run());

  const std::vector<Packet>& outputs = runner.Outputs().Index(0).packets;
  EXPECT_EQ(1, outputs.size());
@@ -60,7 +60,7 @@ TEST(TestConcatenateIntVectorCalculatorTest, OneTimestamp) {

  std::vector<std::vector<int>> inputs = {{1, 2, 3}, {4}, {5, 6}};
  AddInputVectors(inputs, /*timestamp=*/1, &runner);
-  MEDIAPIPE_ASSERT_OK(runner.Run());
+  MP_ASSERT_OK(runner.Run());

  const std::vector<Packet>& outputs = runner.Outputs().Index(0).packets;
  EXPECT_EQ(1, outputs.size());
@@ -81,7 +81,7 @@ TEST(TestConcatenateIntVectorCalculatorTest, TwoInputsAtTwoTimestamps) {
    std::vector<std::vector<int>> inputs = {{0, 2}, {1}, {3, 5}};
    AddInputVectors(inputs, /*timestamp=*/2, &runner);
  }
-  MEDIAPIPE_ASSERT_OK(runner.Run());
+  MP_ASSERT_OK(runner.Run());

  const std::vector<Packet>& outputs = runner.Outputs().Index(0).packets;
  EXPECT_EQ(2, outputs.size());
@@ -106,7 +106,7 @@ TEST(TestConcatenateIntVectorCalculatorTest, OneEmptyStreamStillOutput) {

  std::vector<std::vector<int>> inputs = {{1, 2, 3}};
  AddInputVectors(inputs, /*timestamp=*/1, &runner);
-  MEDIAPIPE_ASSERT_OK(runner.Run());
+  MP_ASSERT_OK(runner.Run());

  const std::vector<Packet>& outputs = runner.Outputs().Index(0).packets;
  EXPECT_EQ(1, outputs.size());
@@ -125,7 +125,7 @@ TEST(TestConcatenateIntVectorCalculatorTest, OneEmptyStreamNoOutput) {

  std::vector<std::vector<int>> inputs = {{1, 2, 3}};
  AddInputVectors(inputs, /*timestamp=*/1, &runner);
-  MEDIAPIPE_ASSERT_OK(runner.Run());
+  MP_ASSERT_OK(runner.Run());

  const std::vector<Packet>& outputs = runner.Outputs().Index(0).packets;
  EXPECT_EQ(0, outputs.size());
@@ -146,7 +146,7 @@ TEST(ConcatenateFloatVectorCalculatorTest, EmptyVectorInputs) {

  std::vector<std::vector<float>> inputs = {{}, {}, {}};
  AddInputVectors(inputs, /*timestamp=*/1, &runner);
-  MEDIAPIPE_ASSERT_OK(runner.Run());
+  MP_ASSERT_OK(runner.Run());

  const std::vector<Packet>& outputs = runner.Outputs().Index(0).packets;
  EXPECT_EQ(1, outputs.size());
@@ -162,7 +162,7 @@ TEST(ConcatenateFloatVectorCalculatorTest, OneTimestamp) {
  std::vector<std::vector<float>> inputs = {
      {1.0f, 2.0f, 3.0f}, {4.0f}, {5.0f, 6.0f}};
  AddInputVectors(inputs, /*timestamp=*/1, &runner);
-  MEDIAPIPE_ASSERT_OK(runner.Run());
+  MP_ASSERT_OK(runner.Run());

  const std::vector<Packet>& outputs = runner.Outputs().Index(0).packets;
  EXPECT_EQ(1, outputs.size());
@@ -185,7 +185,7 @@ TEST(ConcatenateFloatVectorCalculatorTest, TwoInputsAtTwoTimestamps) {
        {0.0f, 2.0f}, {1.0f}, {3.0f, 5.0f}};
    AddInputVectors(inputs, /*timestamp=*/2, &runner);
  }
-  MEDIAPIPE_ASSERT_OK(runner.Run());
+  MP_ASSERT_OK(runner.Run());

  const std::vector<Packet>& outputs = runner.Outputs().Index(0).packets;
  EXPECT_EQ(2, outputs.size());
@@ -210,7 +210,7 @@ TEST(ConcatenateFloatVectorCalculatorTest, OneEmptyStreamStillOutput) {

  std::vector<std::vector<float>> inputs = {{1.0f, 2.0f, 3.0f}};
  AddInputVectors(inputs, /*timestamp=*/1, &runner);
-  MEDIAPIPE_ASSERT_OK(runner.Run());
+  MP_ASSERT_OK(runner.Run());

  const std::vector<Packet>& outputs = runner.Outputs().Index(0).packets;
  EXPECT_EQ(1, outputs.size());
@@ -229,10 +229,173 @@ TEST(ConcatenateFloatVectorCalculatorTest, OneEmptyStreamNoOutput) {

  std::vector<std::vector<float>> inputs = {{1.0f, 2.0f, 3.0f}};
  AddInputVectors(inputs, /*timestamp=*/1, &runner);
-  MEDIAPIPE_ASSERT_OK(runner.Run());
+  MP_ASSERT_OK(runner.Run());

  const std::vector<Packet>& outputs = runner.Outputs().Index(0).packets;
  EXPECT_EQ(0, outputs.size());
 }

+typedef ConcatenateVectorCalculator<std::unique_ptr<int>>
+    TestConcatenateUniqueIntPtrCalculator;
+REGISTER_CALCULATOR(TestConcatenateUniqueIntPtrCalculator);
+
+TEST(TestConcatenateUniqueIntVectorCalculatorTest, ConsumeOneTimestamp) {
+  /* Note: We don't use CalculatorRunner for this test because it keeps copies
+   * of input packets, so packets sent to the graph don't have sole ownership.
+   * The test needs to send packets that own the data.
+   */
+  CalculatorGraphConfig graph_config =
+      ParseTextProtoOrDie<CalculatorGraphConfig>(R"(
+        input_stream: "in_1"
+        input_stream: "in_2"
+        input_stream: "in_3"
+        node {
+          calculator: "TestConcatenateUniqueIntPtrCalculator"
+          input_stream: "in_1"
+          input_stream: "in_2"
+          input_stream: "in_3"
+          output_stream: "out"
+        }
+      )");
+
+  std::vector<Packet> outputs;
+  tool::AddVectorSink("out", &graph_config, &outputs);
+
+  CalculatorGraph graph;
+  MP_EXPECT_OK(graph.Initialize(graph_config));
+  MP_EXPECT_OK(graph.StartRun({}));
+
+  // input1 : {0, 1, 2}
+  std::unique_ptr<std::vector<std::unique_ptr<int>>> input_1 =
+      absl::make_unique<std::vector<std::unique_ptr<int>>>(3);
+  for (int i = 0; i < 3; ++i) {
+    input_1->at(i) = absl::make_unique<int>(i);
+  }
+  // input2: {3}
+  std::unique_ptr<std::vector<std::unique_ptr<int>>> input_2 =
+      absl::make_unique<std::vector<std::unique_ptr<int>>>(1);
+  input_2->at(0) = absl::make_unique<int>(3);
+  // input3: {4, 5}
+  std::unique_ptr<std::vector<std::unique_ptr<int>>> input_3 =
+      absl::make_unique<std::vector<std::unique_ptr<int>>>(2);
+  input_3->at(0) = absl::make_unique<int>(4);
+  input_3->at(1) = absl::make_unique<int>(5);
+
+  MP_EXPECT_OK(graph.AddPacketToInputStream(
+      "in_1", Adopt(input_1.release()).At(Timestamp(1))));
+  MP_EXPECT_OK(graph.AddPacketToInputStream(
+      "in_2", Adopt(input_2.release()).At(Timestamp(1))));
+  MP_EXPECT_OK(graph.AddPacketToInputStream(
+      "in_3", Adopt(input_3.release()).At(Timestamp(1))));
+
+  MP_EXPECT_OK(graph.WaitUntilIdle());
+  MP_EXPECT_OK(graph.CloseAllPacketSources());
+  MP_EXPECT_OK(graph.WaitUntilDone());
+
+  EXPECT_EQ(1, outputs.size());
+  EXPECT_EQ(Timestamp(1), outputs[0].Timestamp());
+  const std::vector<std::unique_ptr<int>>& result =
+      outputs[0].Get<std::vector<std::unique_ptr<int>>>();
+  EXPECT_EQ(6, result.size());
+  for (int i = 0; i < 6; ++i) {
+    const std::unique_ptr<int>& v = result[i];
+    EXPECT_EQ(i, *v);
+  }
+}
+
+TEST(TestConcatenateUniqueIntVectorCalculatorTest, OneEmptyStreamStillOutput) {
+  /* Note: We don't use CalculatorRunner for this test because it keeps copies
+   * of input packets, so packets sent to the graph don't have sole ownership.
+   * The test needs to send packets that own the data.
+   */
+  CalculatorGraphConfig graph_config =
+      ParseTextProtoOrDie<CalculatorGraphConfig>(R"(
+        input_stream: "in_1"
+        input_stream: "in_2"
+        node {
+          calculator: "TestConcatenateUniqueIntPtrCalculator"
+          input_stream: "in_1"
+          input_stream: "in_2"
+          output_stream: "out"
+        }
+      )");
+
+  std::vector<Packet> outputs;
+  tool::AddVectorSink("out", &graph_config, &outputs);
+
+  CalculatorGraph graph;
+  MP_EXPECT_OK(graph.Initialize(graph_config));
+  MP_EXPECT_OK(graph.StartRun({}));
+
+  // input1 : {0, 1, 2}
+  std::unique_ptr<std::vector<std::unique_ptr<int>>> input_1 =
+      absl::make_unique<std::vector<std::unique_ptr<int>>>(3);
+  for (int i = 0; i < 3; ++i) {
+    input_1->at(i) = absl::make_unique<int>(i);
+  }
+
+  MP_EXPECT_OK(graph.AddPacketToInputStream(
+      "in_1", Adopt(input_1.release()).At(Timestamp(1))));
+
+  MP_EXPECT_OK(graph.WaitUntilIdle());
+  MP_EXPECT_OK(graph.CloseAllPacketSources());
+  MP_EXPECT_OK(graph.WaitUntilDone());
+
+  EXPECT_EQ(1, outputs.size());
+  EXPECT_EQ(Timestamp(1), outputs[0].Timestamp());
+  const std::vector<std::unique_ptr<int>>& result =
+      outputs[0].Get<std::vector<std::unique_ptr<int>>>();
+  EXPECT_EQ(3, result.size());
+  for (int i = 0; i < 3; ++i) {
+    const std::unique_ptr<int>& v = result[i];
+    EXPECT_EQ(i, *v);
+  }
+}
+
+TEST(TestConcatenateUniqueIntVectorCalculatorTest, OneEmptyStreamNoOutput) {
+  /* Note: We don't use CalculatorRunner for this test because it keeps copies
+   * of input packets, so packets sent to the graph don't have sole ownership.
+   * The test needs to send packets that own the data.
+   */
+  CalculatorGraphConfig graph_config =
+      ParseTextProtoOrDie<CalculatorGraphConfig>(R"(
+        input_stream: "in_1"
+        input_stream: "in_2"
+        node {
+          calculator: "TestConcatenateUniqueIntPtrCalculator"
+          input_stream: "in_1"
+          input_stream: "in_2"
+          output_stream: "out"
+          options {
+            [mediapipe.ConcatenateVectorCalculatorOptions.ext] {
+              only_emit_if_all_present: true
+            }
+          }
+        }
+      )");
+
+  std::vector<Packet> outputs;
+  tool::AddVectorSink("out", &graph_config, &outputs);
+
+  CalculatorGraph graph;
+  MP_EXPECT_OK(graph.Initialize(graph_config));
+  MP_EXPECT_OK(graph.StartRun({}));
+
+  // input1 : {0, 1, 2}
+  std::unique_ptr<std::vector<std::unique_ptr<int>>> input_1 =
+      absl::make_unique<std::vector<std::unique_ptr<int>>>(3);
+  for (int i = 0; i < 3; ++i) {
+    input_1->at(i) = absl::make_unique<int>(i);
+  }
+
+  MP_EXPECT_OK(graph.AddPacketToInputStream(
+      "in_1", Adopt(input_1.release()).At(Timestamp(1))));
+
+  MP_EXPECT_OK(graph.WaitUntilIdle());
+  MP_EXPECT_OK(graph.CloseAllPacketSources());
+  MP_EXPECT_OK(graph.WaitUntilDone());
+
+  EXPECT_EQ(0, outputs.size());
+}
+
 }  // namespace mediapipe
@@ -0,0 +1,116 @@
+// Copyright 2020 The MediaPipe Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include <string>
+
+#include "mediapipe/calculators/core/constant_side_packet_calculator.pb.h"
+#include "mediapipe/framework/calculator_framework.h"
+#include "mediapipe/framework/collection_item_id.h"
+#include "mediapipe/framework/port/canonical_errors.h"
+#include "mediapipe/framework/port/ret_check.h"
+#include "mediapipe/framework/port/status.h"
+
+namespace mediapipe {
+
+// Generates an output side packet or multiple output side packets according to
+// the specified options.
+//
+// Example configs:
+// node {
+//   calculator: "ConstantSidePacketCalculator"
+//   output_side_packet: "PACKET:packet"
+//   options: {
+//     [mediapipe.ConstantSidePacketCalculatorOptions.ext]: {
+//       packet { int_value: 2 }
+//     }
+//   }
+// }
+//
+// node {
+//   calculator: "ConstantSidePacketCalculator"
+//   output_side_packet: "PACKET:0:int_packet"
+//   output_side_packet: "PACKET:1:bool_packet"
+//   options: {
+//     [mediapipe.ConstantSidePacketCalculatorOptions.ext]: {
+//       packet { int_value: 2 }
+//       packet { bool_value: true }
+//     }
+//   }
+// }
+class ConstantSidePacketCalculator : public CalculatorBase {
+ public:
+  static ::mediapipe::Status GetContract(CalculatorContract* cc) {
+    const auto& options = cc->Options().GetExtension(
+        ::mediapipe::ConstantSidePacketCalculatorOptions::ext);
+    RET_CHECK_EQ(cc->OutputSidePackets().NumEntries(kPacketTag),
+                 options.packet_size())
+        << "Number of output side packets has to be same as number of packets "
+           "configured in options.";
+
+    int index = 0;
+    for (CollectionItemId id = cc->OutputSidePackets().BeginId(kPacketTag);
+         id != cc->OutputSidePackets().EndId(kPacketTag); ++id, ++index) {
+      const auto& packet_options = options.packet(index);
+      auto& packet = cc->OutputSidePackets().Get(id);
+      if (packet_options.has_int_value()) {
+        packet.Set<int>();
+      } else if (packet_options.has_float_value()) {
+        packet.Set<float>();
+      } else if (packet_options.has_bool_value()) {
+        packet.Set<bool>();
+      } else if (packet_options.has_string_value()) {
+        packet.Set<std::string>();
+      } else {
+        return ::mediapipe::InvalidArgumentError(
+            "None of supported values were specified in options.");
+      }
+    }
+    return ::mediapipe::OkStatus();
+  }
+
+  ::mediapipe::Status Open(CalculatorContext* cc) override {
+    const auto& options = cc->Options().GetExtension(
+        ::mediapipe::ConstantSidePacketCalculatorOptions::ext);
+    int index = 0;
+    for (CollectionItemId id = cc->OutputSidePackets().BeginId(kPacketTag);
+         id != cc->OutputSidePackets().EndId(kPacketTag); ++id, ++index) {
+      auto& packet = cc->OutputSidePackets().Get(id);
+      const auto& packet_options = options.packet(index);
+      if (packet_options.has_int_value()) {
+        packet.Set(MakePacket<int>(packet_options.int_value()));
+      } else if (packet_options.has_float_value()) {
+        packet.Set(MakePacket<float>(packet_options.float_value()));
+      } else if (packet_options.has_bool_value()) {
+        packet.Set(MakePacket<bool>(packet_options.bool_value()));
+      } else if (packet_options.has_string_value()) {
+        packet.Set(MakePacket<std::string>(packet_options.string_value()));
+      } else {
+        return ::mediapipe::InvalidArgumentError(
+            "None of supported values were specified in options.");
+      }
+    }
+    return ::mediapipe::OkStatus();
+  }
+
+  ::mediapipe::Status Process(CalculatorContext* cc) override {
+    return ::mediapipe::OkStatus();
+  }
+
+ private:
+  static constexpr const char* kPacketTag = "PACKET";
+};
+
+REGISTER_CALCULATOR(ConstantSidePacketCalculator);
+
+}  // namespace mediapipe
@@ -0,0 +1,36 @@
+// Copyright 2020 The MediaPipe Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+syntax = "proto2";
+
+package mediapipe;
+
+import "mediapipe/framework/calculator.proto";
+
+message ConstantSidePacketCalculatorOptions {
+  extend CalculatorOptions {
+    optional ConstantSidePacketCalculatorOptions ext = 291214597;
+  }
+
+  message ConstantSidePacket {
+    oneof value {
+      int32 int_value = 1;
+      float float_value = 2;
+      bool bool_value = 3;
+      string string_value = 4;
+    }
+  }
+
+  repeated ConstantSidePacket packet = 1;
+}
@@ -0,0 +1,196 @@
+// Copyright 2020 The MediaPipe Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include <string>
+
+#include "absl/strings/string_view.h"
+#include "absl/strings/substitute.h"
+#include "mediapipe/framework/calculator_framework.h"
+#include "mediapipe/framework/port/gmock.h"
+#include "mediapipe/framework/port/gtest.h"
+#include "mediapipe/framework/port/parse_text_proto.h"
+#include "mediapipe/framework/port/status.h"
+#include "mediapipe/framework/port/status_matchers.h"
+
+namespace mediapipe {
+
+template <typename T>
+void DoTestSingleSidePacket(absl::string_view packet_spec,
+                            const T& expected_value) {
+  static constexpr absl::string_view graph_config_template = R"(
+        node {
+          calculator: "ConstantSidePacketCalculator"
+          output_side_packet: "PACKET:packet"
+          options: {
+            [mediapipe.ConstantSidePacketCalculatorOptions.ext]: {
+              packet $0
+            }
+          }
+        }
+      )";
+  CalculatorGraphConfig graph_config =
+      ::mediapipe::ParseTextProtoOrDie<CalculatorGraphConfig>(
+          absl::Substitute(graph_config_template, packet_spec));
+  CalculatorGraph graph;
+  MP_ASSERT_OK(graph.Initialize(graph_config));
+  MP_ASSERT_OK(graph.StartRun({}));
+  MP_ASSERT_OK(graph.WaitUntilIdle());
+
+  MP_ASSERT_OK(graph.GetOutputSidePacket("packet"));
+  auto actual_value =
+      graph.GetOutputSidePacket("packet").ValueOrDie().template Get<T>();
+  EXPECT_EQ(actual_value, expected_value);
+}
+
+TEST(ConstantSidePacketCalculatorTest, EveryPossibleType) {
+  DoTestSingleSidePacket("{ int_value: 2 }", 2);
+  DoTestSingleSidePacket("{ float_value: 6.5f }", 6.5f);
+  DoTestSingleSidePacket("{ bool_value: true }", true);
+  DoTestSingleSidePacket<std::string>(R"({ string_value: "str" })", "str");
+}
+
+TEST(ConstantSidePacketCalculatorTest, MultiplePackets) {
+  CalculatorGraphConfig graph_config =
+      ::mediapipe::ParseTextProtoOrDie<CalculatorGraphConfig>(R"(
+        node {
+          calculator: "ConstantSidePacketCalculator"
+          output_side_packet: "PACKET:0:int_packet"
+          output_side_packet: "PACKET:1:float_packet"
+          output_side_packet: "PACKET:2:bool_packet"
+          output_side_packet: "PACKET:3:string_packet"
+          output_side_packet: "PACKET:4:another_string_packet"
+          output_side_packet: "PACKET:5:another_int_packet"
+          options: {
+            [mediapipe.ConstantSidePacketCalculatorOptions.ext]: {
+              packet { int_value: 256 }
+              packet { float_value: 0.5f }
+              packet { bool_value: false }
+              packet { string_value: "string" }
+              packet { string_value: "another string" }
+              packet { int_value: 128 }
+            }
+          }
+        }
+      )");
+  CalculatorGraph graph;
+  MP_ASSERT_OK(graph.Initialize(graph_config));
+  MP_ASSERT_OK(graph.StartRun({}));
+  MP_ASSERT_OK(graph.WaitUntilIdle());
+
+  MP_ASSERT_OK(graph.GetOutputSidePacket("int_packet"));
+  EXPECT_EQ(graph.GetOutputSidePacket("int_packet").ValueOrDie().Get<int>(),
+            256);
+  MP_ASSERT_OK(graph.GetOutputSidePacket("float_packet"));
+  EXPECT_EQ(graph.GetOutputSidePacket("float_packet").ValueOrDie().Get<float>(),
+            0.5f);
+  MP_ASSERT_OK(graph.GetOutputSidePacket("bool_packet"));
+  EXPECT_FALSE(
+      graph.GetOutputSidePacket("bool_packet").ValueOrDie().Get<bool>());
+  MP_ASSERT_OK(graph.GetOutputSidePacket("string_packet"));
+  EXPECT_EQ(graph.GetOutputSidePacket("string_packet")
+                .ValueOrDie()
+                .Get<std::string>(),
+            "string");
+  MP_ASSERT_OK(graph.GetOutputSidePacket("another_string_packet"));
+  EXPECT_EQ(graph.GetOutputSidePacket("another_string_packet")
+                .ValueOrDie()
+                .Get<std::string>(),
+            "another string");
+  MP_ASSERT_OK(graph.GetOutputSidePacket("another_int_packet"));
+  EXPECT_EQ(
+      graph.GetOutputSidePacket("another_int_packet").ValueOrDie().Get<int>(),
+      128);
+}
+
+TEST(ConstantSidePacketCalculatorTest, ProcessingPacketsWithCorrectTagOnly) {
+  CalculatorGraphConfig graph_config =
+      ::mediapipe::ParseTextProtoOrDie<CalculatorGraphConfig>(R"(
+        node {
+          calculator: "ConstantSidePacketCalculator"
+          output_side_packet: "PACKET:0:int_packet"
+          output_side_packet: "no_tag0"
+          output_side_packet: "PACKET:1:float_packet"
+          output_side_packet: "INCORRECT_TAG:0:name1"
+          output_side_packet: "PACKET:2:bool_packet"
+          output_side_packet: "PACKET:3:string_packet"
+          output_side_packet: "no_tag2"
+          output_side_packet: "INCORRECT_TAG:1:name2"
+          options: {
+            [mediapipe.ConstantSidePacketCalculatorOptions.ext]: {
+              packet { int_value: 256 }
+              packet { float_value: 0.5f }
+              packet { bool_value: false }
+              packet { string_value: "string" }
+            }
+          }
+        }
+      )");
+  CalculatorGraph graph;
+  MP_ASSERT_OK(graph.Initialize(graph_config));
+  MP_ASSERT_OK(graph.StartRun({}));
+  MP_ASSERT_OK(graph.WaitUntilIdle());
+
+  MP_ASSERT_OK(graph.GetOutputSidePacket("int_packet"));
+  EXPECT_EQ(graph.GetOutputSidePacket("int_packet").ValueOrDie().Get<int>(),
+            256);
+  MP_ASSERT_OK(graph.GetOutputSidePacket("float_packet"));
+  EXPECT_EQ(graph.GetOutputSidePacket("float_packet").ValueOrDie().Get<float>(),
+            0.5f);
+  MP_ASSERT_OK(graph.GetOutputSidePacket("bool_packet"));
+  EXPECT_FALSE(
+      graph.GetOutputSidePacket("bool_packet").ValueOrDie().Get<bool>());
+  MP_ASSERT_OK(graph.GetOutputSidePacket("string_packet"));
+  EXPECT_EQ(graph.GetOutputSidePacket("string_packet")
+                .ValueOrDie()
+                .Get<std::string>(),
+            "string");
+}
+
+TEST(ConstantSidePacketCalculatorTest, IncorrectConfig_MoreOptionsThanPackets) {
+  CalculatorGraphConfig graph_config =
+      ::mediapipe::ParseTextProtoOrDie<CalculatorGraphConfig>(R"(
+        node {
+          calculator: "ConstantSidePacketCalculator"
+          output_side_packet: "PACKET:int_packet"
+          options: {
+            [mediapipe.ConstantSidePacketCalculatorOptions.ext]: {
+              packet { int_value: 256 }
+              packet { float_value: 0.5f }
+            }
+          }
+        }
+      )");
+  CalculatorGraph graph;
+  EXPECT_FALSE(graph.Initialize(graph_config).ok());
+}
+
+TEST(ConstantSidePacketCalculatorTest, IncorrectConfig_MorePacketsThanOptions) {
+  CalculatorGraphConfig graph_config =
+      ::mediapipe::ParseTextProtoOrDie<CalculatorGraphConfig>(R"(
+        node {
+          calculator: "ConstantSidePacketCalculator"
+          output_side_packet: "PACKET:0:int_packet"
+          output_side_packet: "PACKET:1:float_packet"
+          options: {
+            [mediapipe.ConstantSidePacketCalculatorOptions.ext]: {
+              packet { int_value: 256 }
+            }
+          }
+        }
+      )");
+  CalculatorGraph graph;
+  EXPECT_FALSE(graph.Initialize(graph_config).ok());
+}
+
+}  // namespace mediapipe
@@ -0,0 +1,90 @@
+// Copyright 2019 The MediaPipe Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include <cfloat>
+
+#include "mediapipe/calculators/core/dequantize_byte_array_calculator.pb.h"
+#include "mediapipe/framework/calculator_framework.h"
+#include "mediapipe/framework/port/canonical_errors.h"
+#include "mediapipe/framework/port/status.h"
+
+// Dequantizes a byte array to a vector of floats.
+//
+// Example config:
+//   node {
+//     calculator: "DequantizeByteArrayCalculator"
+//     input_stream: "ENCODED:encoded"
+//     output_stream: "FLOAT_VECTOR:float_vector"
+//     options {
+//       [mediapipe.DequantizeByteArrayCalculatorOptions.ext]: {
+//         max_quantized_value: 2
+//         min_quantized_value: -2
+//       }
+//     }
+//   }
+namespace mediapipe {
+
+class DequantizeByteArrayCalculator : public CalculatorBase {
+ public:
+  static ::mediapipe::Status GetContract(CalculatorContract* cc) {
+    cc->Inputs().Tag("ENCODED").Set<std::string>();
+    cc->Outputs().Tag("FLOAT_VECTOR").Set<std::vector<float>>();
+    return ::mediapipe::OkStatus();
+  }
+
+  ::mediapipe::Status Open(CalculatorContext* cc) final {
+    const auto options =
+        cc->Options<::mediapipe::DequantizeByteArrayCalculatorOptions>();
+    if (!options.has_max_quantized_value() ||
+        !options.has_min_quantized_value()) {
+      return ::mediapipe::InvalidArgumentError(
+          "Both max_quantized_value and min_quantized_value must be provided "
+          "in DequantizeByteArrayCalculatorOptions.");
+    }
+    float max_quantized_value = options.max_quantized_value();
+    float min_quantized_value = options.min_quantized_value();
+    if (max_quantized_value < min_quantized_value + FLT_EPSILON) {
+      return ::mediapipe::InvalidArgumentError(
+          "max_quantized_value must be greater than min_quantized_value.");
+    }
+    float range = max_quantized_value - min_quantized_value;
+    scalar_ = range / 255.0;
+    bias_ = (range / 512.0) + min_quantized_value;
+    return ::mediapipe::OkStatus();
+  }
+
+  ::mediapipe::Status Process(CalculatorContext* cc) final {
+    const std::string& encoded =
+        cc->Inputs().Tag("ENCODED").Value().Get<std::string>();
+    std::vector<float> float_vector;
+    float_vector.reserve(encoded.length());
+    for (int i = 0; i < encoded.length(); ++i) {
+      float_vector.push_back(
+          static_cast<unsigned char>(encoded.at(i)) * scalar_ + bias_);
+    }
+    cc->Outputs()
+        .Tag("FLOAT_VECTOR")
+        .AddPacket(MakePacket<std::vector<float>>(float_vector)
+                       .At(cc->InputTimestamp()));
+    return ::mediapipe::OkStatus();
+  }
+
+ private:
+  float scalar_;
+  float bias_;
+};
+
+REGISTER_CALCULATOR(DequantizeByteArrayCalculator);
+
+}  // namespace mediapipe
@@ -0,0 +1,28 @@
+// Copyright 2019 The MediaPipe Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+syntax = "proto2";
+
+package mediapipe;
+
+import "mediapipe/framework/calculator.proto";
+
+message DequantizeByteArrayCalculatorOptions {
+  extend CalculatorOptions {
+    optional DequantizeByteArrayCalculatorOptions ext = 272316343;
+  }
+
+  optional float max_quantized_value = 1;
+  optional float min_quantized_value = 2;
+}
@@ -0,0 +1,137 @@
+// Copyright 2019 The MediaPipe Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include <string>
+#include <vector>
+
+#include "mediapipe/framework/calculator_framework.h"
+#include "mediapipe/framework/calculator_runner.h"
+#include "mediapipe/framework/port/gmock.h"
+#include "mediapipe/framework/port/gtest.h"
+#include "mediapipe/framework/port/parse_text_proto.h"
+#include "mediapipe/framework/port/status.h"
+#include "mediapipe/framework/port/status_matchers.h"  // NOLINT
+
+namespace mediapipe {
+
+TEST(QuantizeFloatVectorCalculatorTest, WrongConfig) {
+  CalculatorGraphConfig::Node node_config =
+      ParseTextProtoOrDie<CalculatorGraphConfig::Node>(R"(
+        calculator: "DequantizeByteArrayCalculator"
+        input_stream: "ENCODED:encoded"
+        output_stream: "FLOAT_VECTOR:float_vector"
+        options {
+          [mediapipe.DequantizeByteArrayCalculatorOptions.ext]: {
+            max_quantized_value: 2
+          }
+        }
+      )");
+  CalculatorRunner runner(node_config);
+  std::string empty_string;
+  runner.MutableInputs()->Tag("ENCODED").packets.push_back(
+      MakePacket<std::string>(empty_string).At(Timestamp(0)));
+  auto status = runner.Run();
+  EXPECT_FALSE(status.ok());
+  EXPECT_THAT(
+      status.message(),
+      testing::HasSubstr(
+          "Both max_quantized_value and min_quantized_value must be provided"));
+}
+
+TEST(QuantizeFloatVectorCalculatorTest, WrongConfig2) {
+  CalculatorGraphConfig::Node node_config =
+      ParseTextProtoOrDie<CalculatorGraphConfig::Node>(R"(
+        calculator: "DequantizeByteArrayCalculator"
+        input_stream: "ENCODED:encoded"
+        output_stream: "FLOAT_VECTOR:float_vector"
+        options {
+          [mediapipe.DequantizeByteArrayCalculatorOptions.ext]: {
+            max_quantized_value: -2
+            min_quantized_value: 2
+          }
+        }
+      )");
+  CalculatorRunner runner(node_config);
+  std::string empty_string;
+  runner.MutableInputs()->Tag("ENCODED").packets.push_back(
+      MakePacket<std::string>(empty_string).At(Timestamp(0)));
+  auto status = runner.Run();
+  EXPECT_FALSE(status.ok());
+  EXPECT_THAT(
+      status.message(),
+      testing::HasSubstr(
+          "max_quantized_value must be greater than min_quantized_value"));
+}
+
+TEST(QuantizeFloatVectorCalculatorTest, WrongConfig3) {
+  CalculatorGraphConfig::Node node_config =
+      ParseTextProtoOrDie<CalculatorGraphConfig::Node>(R"(
+        calculator: "DequantizeByteArrayCalculator"
+        input_stream: "ENCODED:encoded"
+        output_stream: "FLOAT_VECTOR:float_vector"
+        options {
+          [mediapipe.DequantizeByteArrayCalculatorOptions.ext]: {
+            max_quantized_value: 1
+            min_quantized_value: 1
+          }
+        }
+      )");
+  CalculatorRunner runner(node_config);
+  std::string empty_string;
+  runner.MutableInputs()->Tag("ENCODED").packets.push_back(
+      MakePacket<std::string>(empty_string).At(Timestamp(0)));
+  auto status = runner.Run();
+  EXPECT_FALSE(status.ok());
+  EXPECT_THAT(
+      status.message(),
+      testing::HasSubstr(
+          "max_quantized_value must be greater than min_quantized_value"));
+}
+
+TEST(DequantizeByteArrayCalculatorTest, TestDequantization) {
+  CalculatorGraphConfig::Node node_config =
+      ParseTextProtoOrDie<CalculatorGraphConfig::Node>(R"(
+        calculator: "DequantizeByteArrayCalculator"
+        input_stream: "ENCODED:encoded"
+        output_stream: "FLOAT_VECTOR:float_vector"
+        options {
+          [mediapipe.DequantizeByteArrayCalculatorOptions.ext]: {
+            max_quantized_value: 2
+            min_quantized_value: -2
+          }
+        }
+      )");
+  CalculatorRunner runner(node_config);
+  unsigned char input[4] = {0x7F, 0xFF, 0x00, 0x01};
+  runner.MutableInputs()->Tag("ENCODED").packets.push_back(
+      MakePacket<std::string>(
+          std::string(reinterpret_cast<char const*>(input), 4))
+          .At(Timestamp(0)));
+  auto status = runner.Run();
+  MP_ASSERT_OK(runner.Run());
+  const std::vector<Packet>& outputs =
+      runner.Outputs().Tag("FLOAT_VECTOR").packets;
+  EXPECT_EQ(1, outputs.size());
+  const std::vector<float>& result = outputs[0].Get<std::vector<float>>();
+  ASSERT_FALSE(result.empty());
+  EXPECT_EQ(4, result.size());
+  EXPECT_NEAR(0, result[0], 0.01);
+  EXPECT_NEAR(2, result[1], 0.01);
+  EXPECT_NEAR(-2, result[2], 0.01);
+  EXPECT_NEAR(-1.976, result[3], 0.01);
+
+  EXPECT_EQ(Timestamp(0), outputs[0].Timestamp());
+}
+
+}  // namespace mediapipe
@@ -0,0 +1,49 @@
+// Copyright 2019 The MediaPipe Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "mediapipe/calculators/core/end_loop_calculator.h"
+
+#include <vector>
+
+#include "mediapipe/framework/formats/classification.pb.h"
+#include "mediapipe/framework/formats/landmark.pb.h"
+#include "mediapipe/framework/formats/rect.pb.h"
+#include "mediapipe/util/render_data.pb.h"
+#include "tensorflow/lite/interpreter.h"
+
+namespace mediapipe {
+
+typedef EndLoopCalculator<std::vector<::mediapipe::NormalizedRect>>
+    EndLoopNormalizedRectCalculator;
+REGISTER_CALCULATOR(EndLoopNormalizedRectCalculator);
+
+typedef EndLoopCalculator<std::vector<::mediapipe::NormalizedLandmarkList>>
+    EndLoopNormalizedLandmarkListVectorCalculator;
+REGISTER_CALCULATOR(EndLoopNormalizedLandmarkListVectorCalculator);
+
+typedef EndLoopCalculator<std::vector<bool>> EndLoopBooleanCalculator;
+REGISTER_CALCULATOR(EndLoopBooleanCalculator);
+
+typedef EndLoopCalculator<std::vector<::mediapipe::RenderData>>
+    EndLoopRenderDataCalculator;
+REGISTER_CALCULATOR(EndLoopRenderDataCalculator);
+
+typedef EndLoopCalculator<std::vector<::mediapipe::ClassificationList>>
+    EndLoopClassificationListCalculator;
+REGISTER_CALCULATOR(EndLoopClassificationListCalculator);
+
+typedef EndLoopCalculator<std::vector<TfLiteTensor>> EndLoopTensorCalculator;
+REGISTER_CALCULATOR(EndLoopTensorCalculator);
+
+}  // namespace mediapipe
@@ -0,0 +1,106 @@
+// Copyright 2019 The MediaPipe Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef MEDIAPIPE_CALCULATORS_CORE_END_LOOP_CALCULATOR_H_
+#define MEDIAPIPE_CALCULATORS_CORE_END_LOOP_CALCULATOR_H_
+
+#include "mediapipe/framework/calculator_context.h"
+#include "mediapipe/framework/calculator_contract.h"
+#include "mediapipe/framework/calculator_framework.h"
+#include "mediapipe/framework/collection_item_id.h"
+#include "mediapipe/framework/port/integral_types.h"
+#include "mediapipe/framework/port/ret_check.h"
+#include "mediapipe/framework/port/status.h"
+
+namespace mediapipe {
+
+// Calculator for completing the processing of loops on iterable collections
+// inside a MediaPipe graph. The EndLoopCalculator collects all input packets
+// from ITEM input_stream into a collection and upon receiving the flush signal
+// from the "BATCH_END" tagged input stream, it emits the aggregated results
+// at the original timestamp contained in the "BATCH_END" input stream.
+//
+// It is designed to be used like:
+//
+// node {
+//   calculator:    "BeginLoopWithIterableCalculator"
+//   input_stream:  "ITERABLE:input_iterable"      # IterableT @ext_ts
+//   output_stream: "ITEM:input_element"           # ItemT     @loop_internal_ts
+//   output_stream: "BATCH_END:ext_ts"             # Timestamp @loop_internal_ts
+// }
+//
+// node {
+//   calculator:    "ElementToBlaConverterSubgraph"
+//   input_stream:  "ITEM:input_to_loop_body"      # ItemT     @loop_internal_ts
+//   output_stream: "BLA:output_of_loop_body"      # ItemU     @loop_internal_ts
+// }
+//
+// node {
+//   calculator:    "EndLoopWithOutputCalculator"
+//   input_stream:  "ITEM:output_of_loop_body"     # ItemU     @loop_internal_ts
+//   input_stream:  "BATCH_END:ext_ts"             # Timestamp @loop_internal_ts
+//   output_stream: "OUTPUT:aggregated_result"     # IterableU @ext_ts
+// }
+template <typename IterableT>
+class EndLoopCalculator : public CalculatorBase {
+  using ItemT = typename IterableT::value_type;
+
+ public:
+  static ::mediapipe::Status GetContract(CalculatorContract* cc) {
+    RET_CHECK(cc->Inputs().HasTag("BATCH_END"))
+        << "Missing BATCH_END tagged input_stream.";
+    cc->Inputs().Tag("BATCH_END").Set<Timestamp>();
+
+    RET_CHECK(cc->Inputs().HasTag("ITEM"));
+    cc->Inputs().Tag("ITEM").Set<ItemT>();
+
+    RET_CHECK(cc->Outputs().HasTag("ITERABLE"));
+    cc->Outputs().Tag("ITERABLE").Set<IterableT>();
+    return ::mediapipe::OkStatus();
+  }
+
+  ::mediapipe::Status Process(CalculatorContext* cc) override {
+    if (!cc->Inputs().Tag("ITEM").IsEmpty()) {
+      if (!input_stream_collection_) {
+        input_stream_collection_.reset(new IterableT);
+      }
+      input_stream_collection_->push_back(
+          cc->Inputs().Tag("ITEM").template Get<ItemT>());
+    }
+
+    if (!cc->Inputs().Tag("BATCH_END").Value().IsEmpty()) {  // flush signal
+      Timestamp loop_control_ts =
+          cc->Inputs().Tag("BATCH_END").template Get<Timestamp>();
+      if (input_stream_collection_) {
+        cc->Outputs()
+            .Tag("ITERABLE")
+            .Add(input_stream_collection_.release(), loop_control_ts);
+      } else {
+        // Since there is no collection, inform downstream calculators to not
+        // expect any packet by updating the timestamp bounds.
+        cc->Outputs()
+            .Tag("ITERABLE")
+            .SetNextTimestampBound(Timestamp(loop_control_ts.Value() + 1));
+      }
+    }
+    return ::mediapipe::OkStatus();
+  }
+
+ private:
+  std::unique_ptr<IterableT> input_stream_collection_;
+};
+
+}  // namespace mediapipe
+
+#endif  // MEDIAPIPE_CALCULATORS_CORE_END_LOOP_CALCULATOR_H_
@@ -91,7 +91,7 @@ TEST(FlowLimiterCalculator, OneOutputTest) {
  }

  // Run the calculator.
-  MEDIAPIPE_ASSERT_OK(runner.Run()) << "Calculator execution failed.";
+  MP_ASSERT_OK(runner.Run()) << "Calculator execution failed.";
  const std::vector<Packet>& frame_output_packets =
      runner.Outputs().Index(0).packets;

@@ -117,7 +117,7 @@ TEST(FlowLimiterCalculator, BasicTest) {
  }

  // Run the calculator.
-  MEDIAPIPE_ASSERT_OK(runner.Run()) << "Calculator execution failed.";
+  MP_ASSERT_OK(runner.Run()) << "Calculator execution failed.";
  const std::vector<Packet>& frame_output_packets =
      runner.Outputs().Index(0).packets;

@@ -198,7 +198,7 @@ class FlowLimiterCalculatorTest : public testing::Test {
      close_count_++;
      return ::mediapipe::OkStatus();
    };
-    MEDIAPIPE_ASSERT_OK(graph_.Initialize(
+    MP_ASSERT_OK(graph_.Initialize(
        graph_config_, {
                           {"max_in_flight", MakePacket<int>(max_in_flight)},
                           {"callback_0", Adopt(new auto(semaphore_0_func))},
@@ -209,7 +209,7 @@ class FlowLimiterCalculatorTest : public testing::Test {

  // Adds a packet to a graph input stream.
  void AddPacket(const std::string& input_name, int value) {
-    MEDIAPIPE_EXPECT_OK(graph_.AddPacketToInputStream(
+    MP_EXPECT_OK(graph_.AddPacketToInputStream(
        input_name, MakePacket<int>(value).At(Timestamp(value))));
  }

@@ -277,10 +277,10 @@ class FlowLimiterCalculatorTest : public testing::Test {
 //
 TEST_F(FlowLimiterCalculatorTest, BackEdgeCloses) {
  InitializeGraph(1);
-  MEDIAPIPE_ASSERT_OK(graph_.StartRun({}));
+  MP_ASSERT_OK(graph_.StartRun({}));

  auto send_packet = [this](const std::string& input_name, int64 n) {
-    MEDIAPIPE_EXPECT_OK(graph_.AddPacketToInputStream(
+    MP_EXPECT_OK(graph_.AddPacketToInputStream(
        input_name, MakePacket<int64>(n).At(Timestamp(n))));
  };

@@ -288,14 +288,14 @@ TEST_F(FlowLimiterCalculatorTest, BackEdgeCloses) {
    send_packet("in_1", i * 10);
    // This next input should be dropped.
    send_packet("in_1", i * 10 + 5);
-    MEDIAPIPE_EXPECT_OK(graph_.WaitUntilIdle());
+    MP_EXPECT_OK(graph_.WaitUntilIdle());
    send_packet("in_2", i * 10);
    exit_semaphore_.Release(1);
-    MEDIAPIPE_EXPECT_OK(graph_.WaitUntilIdle());
+    MP_EXPECT_OK(graph_.WaitUntilIdle());
  }
-  MEDIAPIPE_EXPECT_OK(graph_.CloseInputStream("in_1"));
-  MEDIAPIPE_EXPECT_OK(graph_.CloseInputStream("in_2"));
-  MEDIAPIPE_EXPECT_OK(graph_.WaitUntilIdle());
+  MP_EXPECT_OK(graph_.CloseInputStream("in_1"));
+  MP_EXPECT_OK(graph_.CloseInputStream("in_2"));
+  MP_EXPECT_OK(graph_.WaitUntilIdle());

  // All output streams are closed and all output packets are delivered,
  // with stream "in_1" and stream "in_2" closed.
@@ -321,17 +321,17 @@ TEST_F(FlowLimiterCalculatorTest, BackEdgeCloses) {
 // input streams are closed after the last input packet has been processed.
 TEST_F(FlowLimiterCalculatorTest, AllStreamsClose) {
  InitializeGraph(1);
-  MEDIAPIPE_ASSERT_OK(graph_.StartRun({}));
+  MP_ASSERT_OK(graph_.StartRun({}));

  exit_semaphore_.Release(10);
  for (int i = 0; i < 10; i++) {
    AddPacket("in_1", i);
-    MEDIAPIPE_EXPECT_OK(graph_.WaitUntilIdle());
+    MP_EXPECT_OK(graph_.WaitUntilIdle());
    AddPacket("in_2", i);
-    MEDIAPIPE_EXPECT_OK(graph_.WaitUntilIdle());
+    MP_EXPECT_OK(graph_.WaitUntilIdle());
  }
-  MEDIAPIPE_EXPECT_OK(graph_.CloseAllInputStreams());
-  MEDIAPIPE_EXPECT_OK(graph_.WaitUntilIdle());
+  MP_EXPECT_OK(graph_.CloseAllInputStreams());
+  MP_EXPECT_OK(graph_.WaitUntilIdle());

  EXPECT_EQ(TimestampValues(out_1_packets_), TimestampValues(out_2_packets_));
  EXPECT_EQ(TimestampValues(out_1_packets_),
@@ -371,7 +371,7 @@ TEST(FlowLimiterCalculator, TwoStreams) {
  };

  CalculatorGraph graph_;
-  MEDIAPIPE_EXPECT_OK(graph_.Initialize(
+  MP_EXPECT_OK(graph_.Initialize(
      graph_config_,
      {
          {"max_in_flight", MakePacket<int>(1)},
@@ -379,63 +379,63 @@ TEST(FlowLimiterCalculator, TwoStreams) {
           MakePacket<std::function<void(const Packet&)>>(allow_cb)},
      }));

-  MEDIAPIPE_EXPECT_OK(graph_.StartRun({}));
+  MP_EXPECT_OK(graph_.StartRun({}));

  auto send_packet = [&graph_](const std::string& input_name, int n) {
-    MEDIAPIPE_EXPECT_OK(graph_.AddPacketToInputStream(
+    MP_EXPECT_OK(graph_.AddPacketToInputStream(
        input_name, MakePacket<int>(n).At(Timestamp(n))));
  };
  send_packet("in_a", 1);
-  MEDIAPIPE_EXPECT_OK(graph_.WaitUntilIdle());
+  MP_EXPECT_OK(graph_.WaitUntilIdle());
  EXPECT_EQ(allow, false);
  EXPECT_EQ(TimestampValues(a_passed), (std::vector<int64>{1}));
  EXPECT_EQ(TimestampValues(b_passed), (std::vector<int64>{}));

  send_packet("in_a", 2);
  send_packet("in_b", 1);
-  MEDIAPIPE_EXPECT_OK(graph_.WaitUntilIdle());
+  MP_EXPECT_OK(graph_.WaitUntilIdle());
  EXPECT_EQ(TimestampValues(a_passed), (std::vector<int64>{1}));
  EXPECT_EQ(TimestampValues(b_passed), (std::vector<int64>{1}));
  EXPECT_EQ(allow, false);

  send_packet("finished", 1);
-  MEDIAPIPE_EXPECT_OK(graph_.WaitUntilIdle());
+  MP_EXPECT_OK(graph_.WaitUntilIdle());
  EXPECT_EQ(TimestampValues(a_passed), (std::vector<int64>{1}));
  EXPECT_EQ(TimestampValues(b_passed), (std::vector<int64>{1}));
  EXPECT_EQ(allow, true);

  send_packet("in_b", 2);
-  MEDIAPIPE_EXPECT_OK(graph_.WaitUntilIdle());
+  MP_EXPECT_OK(graph_.WaitUntilIdle());
  EXPECT_EQ(TimestampValues(a_passed), (std::vector<int64>{1}));
  EXPECT_EQ(TimestampValues(b_passed), (std::vector<int64>{1}));
  EXPECT_EQ(allow, true);

  send_packet("in_b", 3);
-  MEDIAPIPE_EXPECT_OK(graph_.WaitUntilIdle());
+  MP_EXPECT_OK(graph_.WaitUntilIdle());
  EXPECT_EQ(TimestampValues(a_passed), (std::vector<int64>{1}));
  EXPECT_EQ(TimestampValues(b_passed), (std::vector<int64>{1, 3}));
  EXPECT_EQ(allow, false);

  send_packet("in_b", 4);
-  MEDIAPIPE_EXPECT_OK(graph_.WaitUntilIdle());
+  MP_EXPECT_OK(graph_.WaitUntilIdle());
  EXPECT_EQ(TimestampValues(a_passed), (std::vector<int64>{1}));
  EXPECT_EQ(TimestampValues(b_passed), (std::vector<int64>{1, 3}));
  EXPECT_EQ(allow, false);

  send_packet("in_a", 3);
-  MEDIAPIPE_EXPECT_OK(graph_.WaitUntilIdle());
+  MP_EXPECT_OK(graph_.WaitUntilIdle());
  EXPECT_EQ(TimestampValues(a_passed), (std::vector<int64>{1, 3}));
  EXPECT_EQ(TimestampValues(b_passed), (std::vector<int64>{1, 3}));
  EXPECT_EQ(allow, false);

  send_packet("finished", 3);
-  MEDIAPIPE_EXPECT_OK(graph_.WaitUntilIdle());
+  MP_EXPECT_OK(graph_.WaitUntilIdle());
  EXPECT_EQ(TimestampValues(a_passed), (std::vector<int64>{1, 3}));
  EXPECT_EQ(TimestampValues(b_passed), (std::vector<int64>{1, 3}));
  EXPECT_EQ(allow, true);

-  MEDIAPIPE_EXPECT_OK(graph_.CloseAllInputStreams());
-  MEDIAPIPE_EXPECT_OK(graph_.WaitUntilDone());
+  MP_EXPECT_OK(graph_.CloseAllInputStreams());
+  MP_EXPECT_OK(graph_.WaitUntilDone());
 }

 TEST(FlowLimiterCalculator, CanConsume) {
@@ -465,7 +465,7 @@ TEST(FlowLimiterCalculator, CanConsume) {
  };

  CalculatorGraph graph_;
-  MEDIAPIPE_EXPECT_OK(graph_.Initialize(
+  MP_EXPECT_OK(graph_.Initialize(
      graph_config_,
      {
          {"max_in_flight", MakePacket<int>(1)},
@@ -473,21 +473,21 @@ TEST(FlowLimiterCalculator, CanConsume) {
           MakePacket<std::function<void(const Packet&)>>(allow_cb)},
      }));

-  MEDIAPIPE_EXPECT_OK(graph_.StartRun({}));
+  MP_EXPECT_OK(graph_.StartRun({}));

  auto send_packet = [&graph_](const std::string& input_name, int n) {
-    MEDIAPIPE_EXPECT_OK(graph_.AddPacketToInputStream(
+    MP_EXPECT_OK(graph_.AddPacketToInputStream(
        input_name, MakePacket<int>(n).At(Timestamp(n))));
  };
  send_packet("in", 1);
-  MEDIAPIPE_EXPECT_OK(graph_.WaitUntilIdle());
+  MP_EXPECT_OK(graph_.WaitUntilIdle());
  EXPECT_EQ(allow, false);
  EXPECT_EQ(TimestampValues(in_sampled_packets_), (std::vector<int64>{1}));

-  MEDIAPIPE_EXPECT_OK(in_sampled_packets_[0].Consume<int>());
+  MP_EXPECT_OK(in_sampled_packets_[0].Consume<int>());

-  MEDIAPIPE_EXPECT_OK(graph_.CloseAllInputStreams());
-  MEDIAPIPE_EXPECT_OK(graph_.WaitUntilDone());
+  MP_EXPECT_OK(graph_.CloseAllInputStreams());
+  MP_EXPECT_OK(graph_.WaitUntilDone());
 }

 }  // anonymous namespace
@@ -32,7 +32,7 @@ class GateCalculatorTest : public ::testing::Test {
        ->Tag(control_tag)
        .packets.push_back(MakePacket<bool>(control).At(Timestamp(timestamp)));

-    MEDIAPIPE_ASSERT_OK(runner_->Run()) << "Calculator execution failed.";
+    MP_ASSERT_OK(runner_->Run()) << "Calculator execution failed.";
  }

  void SetRunner(const std::string& proto) {
@@ -217,23 +217,23 @@ class ImmediateMuxCalculatorTest : public ::testing::Test {

    // Start running the graph.
    CalculatorGraph graph;
-    MEDIAPIPE_ASSERT_OK(graph.Initialize(graph_config_));
-    MEDIAPIPE_ASSERT_OK(graph.StartRun({}));
+    MP_ASSERT_OK(graph.Initialize(graph_config_));
+    MP_ASSERT_OK(graph.StartRun({}));

    // Send each packet to the graph in the specified order.
    for (int t = 0; t < input_sets.size(); t++) {
      const std::vector<Packet>& input_set = input_sets[t];
-      MEDIAPIPE_EXPECT_OK(graph.WaitUntilIdle());
+      MP_EXPECT_OK(graph.WaitUntilIdle());
      for (int i = 0; i < input_set.size(); i++) {
        const Packet& packet = input_set[i];
        if (!IsNone(packet)) {
-          MEDIAPIPE_EXPECT_OK(graph.AddPacketToInputStream(
+          MP_EXPECT_OK(graph.AddPacketToInputStream(
              absl::StrCat("input_packets_", i), packet));
        }
      }
    }
-    MEDIAPIPE_ASSERT_OK(graph.CloseAllInputStreams());
-    MEDIAPIPE_ASSERT_OK(graph.WaitUntilDone());
+    MP_ASSERT_OK(graph.CloseAllInputStreams());
+    MP_ASSERT_OK(graph.WaitUntilDone());
  }

  CalculatorGraphConfig graph_config_;
@@ -335,22 +335,22 @@ TEST_F(ImmediateMuxCalculatorTest, Demux) {

  // Start the graph and add five input packets.
  CalculatorGraph graph;
-  MEDIAPIPE_ASSERT_OK(graph.Initialize(
-      graph_config_, {
-                         {"callback_0", Adopt(new auto(wait_0))},
-                         {"callback_1", Adopt(new auto(wait_1))},
-                     }));
-  MEDIAPIPE_ASSERT_OK(graph.ObserveOutputStream("output_packets_0", out_cb));
-  MEDIAPIPE_ASSERT_OK(graph.StartRun({}));
-  MEDIAPIPE_EXPECT_OK(
+  MP_ASSERT_OK(graph.Initialize(graph_config_,
+                                {
+                                    {"callback_0", Adopt(new auto(wait_0))},
+                                    {"callback_1", Adopt(new auto(wait_1))},
+                                }));
+  MP_ASSERT_OK(graph.ObserveOutputStream("output_packets_0", out_cb));
+  MP_ASSERT_OK(graph.StartRun({}));
+  MP_EXPECT_OK(
      graph.AddPacketToInputStream("input_packets_0", PacketAt(10000)));
-  MEDIAPIPE_EXPECT_OK(
+  MP_EXPECT_OK(
      graph.AddPacketToInputStream("input_packets_0", PacketAt(20000)));
-  MEDIAPIPE_EXPECT_OK(
+  MP_EXPECT_OK(
      graph.AddPacketToInputStream("input_packets_0", PacketAt(30000)));
-  MEDIAPIPE_EXPECT_OK(
+  MP_EXPECT_OK(
      graph.AddPacketToInputStream("input_packets_0", PacketAt(40000)));
-  MEDIAPIPE_EXPECT_OK(
+  MP_EXPECT_OK(
      graph.AddPacketToInputStream("input_packets_0", PacketAt(50000)));

  // Release the outputs in order 20000, 10000, 30000, 50000, 40000.
@@ -362,8 +362,8 @@ TEST_F(ImmediateMuxCalculatorTest, Demux) {
  semaphore_0.Release(1);  // 50000
  wait_for([&] { return out_packets.size() >= 3; });
  semaphore_1.Release(1);  // 40000
-  MEDIAPIPE_ASSERT_OK(graph.CloseAllInputStreams());
-  MEDIAPIPE_ASSERT_OK(graph.WaitUntilDone());
+  MP_ASSERT_OK(graph.CloseAllInputStreams());
+  MP_ASSERT_OK(graph.WaitUntilDone());

  // Output packets 10000 and 40000 are superseded and dropped.
  EXPECT_THAT(TimestampValues(out_packets), ElementsAre(20000, 30000, 50000));
@@ -219,7 +219,7 @@ TEST(MatrixMultiplyCalculatorTest, Multiply) {
        Adopt(sample).At(Timestamp(i)));
  }

-  MEDIAPIPE_ASSERT_OK(runner.Run());
+  MP_ASSERT_OK(runner.Run());
  EXPECT_EQ(runner.MutableInputs()->Index(0).packets.size(),
            runner.Outputs().Index(0).packets.size());

@@ -112,7 +112,7 @@ TEST(MatrixSubtractCalculatorTest, SubtractFromInput) {
  runner.MutableInputs()->Tag("MINUEND").packets.push_back(
      Adopt(input_matrix).At(Timestamp(0)));

-  MEDIAPIPE_ASSERT_OK(runner.Run());
+  MP_ASSERT_OK(runner.Run());
  EXPECT_EQ(1, runner.Outputs().Index(0).packets.size());

  EXPECT_EQ(Timestamp(0), runner.Outputs().Index(0).packets[0].Timestamp());
@@ -142,7 +142,7 @@ TEST(MatrixSubtractCalculatorTest, SubtractFromSideMatrix) {
      ->Tag("SUBTRAHEND")
      .packets.push_back(Adopt(input_matrix).At(Timestamp(0)));

-  MEDIAPIPE_ASSERT_OK(runner.Run());
+  MP_ASSERT_OK(runner.Run());
  EXPECT_EQ(1, runner.Outputs().Index(0).packets.size());

  EXPECT_EQ(Timestamp(0), runner.Outputs().Index(0).packets[0].Timestamp());
@@ -0,0 +1,83 @@
+// Copyright 2019 The MediaPipe Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+// Defines MatrixToVectorCalculator.
+#include <math.h>
+
+#include <deque>
+#include <memory>
+#include <string>
+
+#include "Eigen/Core"
+#include "absl/memory/memory.h"
+#include "mediapipe/framework/calculator_framework.h"
+#include "mediapipe/framework/formats/matrix.h"
+#include "mediapipe/framework/port/integral_types.h"
+#include "mediapipe/framework/port/logging.h"
+#include "mediapipe/framework/port/parse_text_proto.h"
+#include "mediapipe/framework/tool/status_util.h"
+#include "mediapipe/util/time_series_util.h"
+
+namespace mediapipe {
+
+// A calculator that converts a Matrix M to a vector containing all the
+// entries of M in column-major order.
+//
+// Example config:
+// node {
+//   calculator: "MatrixToVectorCalculator"
+//   input_stream: "input_matrix"
+//   output_stream: "column_major_vector"
+// }
+class MatrixToVectorCalculator : public CalculatorBase {
+ public:
+  static ::mediapipe::Status GetContract(CalculatorContract* cc) {
+    cc->Inputs().Index(0).Set<Matrix>(
+        // Input Packet containing a Matrix.
+    );
+    cc->Outputs().Index(0).Set<std::vector<float>>(
+        // Output Packet containing a vector, one for each input Packet.
+    );
+    return ::mediapipe::OkStatus();
+  }
+
+  ::mediapipe::Status Open(CalculatorContext* cc) override;
+
+  // Outputs a packet containing a vector for each input packet.
+  ::mediapipe::Status Process(CalculatorContext* cc) override;
+};
+REGISTER_CALCULATOR(MatrixToVectorCalculator);
+
+::mediapipe::Status MatrixToVectorCalculator::Open(CalculatorContext* cc) {
+  // Inform the framework that we don't alter timestamps.
+  cc->SetOffset(mediapipe::TimestampDiff(0));
+  return ::mediapipe::OkStatus();
+}
+
+::mediapipe::Status MatrixToVectorCalculator::Process(CalculatorContext* cc) {
+  const Matrix& input = cc->Inputs().Index(0).Get<Matrix>();
+  auto output = absl::make_unique<std::vector<float>>();
+
+  // The following lines work to convert the Matrix to a vector because Matrix
+  // is an Eigen::MatrixXf and Eigen uses column-major layout by default.
+  output->resize(input.rows() * input.cols());
+  auto output_as_matrix =
+      Eigen::Map<Matrix>(output->data(), input.rows(), input.cols());
+  output_as_matrix = input;
+
+  cc->Outputs().Index(0).Add(output.release(), cc->InputTimestamp());
+  return ::mediapipe::OkStatus();
+}
+
+}  // namespace mediapipe
@@ -0,0 +1,88 @@
+// Copyright 2019 The MediaPipe Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include <memory>
+#include <string>
+#include <vector>
+
+#include "mediapipe/framework/calculator_runner.h"
+#include "mediapipe/framework/formats/matrix.h"
+#include "mediapipe/framework/port/gmock.h"
+#include "mediapipe/framework/port/gtest.h"
+#include "mediapipe/framework/port/integral_types.h"
+#include "mediapipe/framework/port/status_matchers.h"
+#include "mediapipe/framework/tool/validate_type.h"
+#include "mediapipe/util/time_series_test_util.h"
+#include "mediapipe/util/time_series_util.h"
+
+namespace mediapipe {
+namespace {
+
+class MatrixToVectorCalculatorTest
+    : public mediapipe::TimeSeriesCalculatorTest<mediapipe::NoOptions> {
+ protected:
+  void SetUp() override { calculator_name_ = "MatrixToVectorCalculator"; }
+
+  void AppendInput(const std::vector<float>& column_major_data,
+                   int64 timestamp) {
+    ASSERT_EQ(num_input_samples_ * num_input_channels_,
+              column_major_data.size());
+    Eigen::Map<const Matrix> data_map(&column_major_data[0],
+                                      num_input_channels_, num_input_samples_);
+    AppendInputPacket(new Matrix(data_map), timestamp);
+  }
+
+  void SetInputStreamParameters(int num_channels, int num_samples) {
+    num_input_channels_ = num_channels;
+    num_input_samples_ = num_samples;
+    input_sample_rate_ = 100;
+    input_packet_rate_ = 20.0;
+  }
+
+  void SetInputHeader(int num_channels, int num_samples) {
+    SetInputStreamParameters(num_channels, num_samples);
+    FillInputHeader();
+  }
+
+  void CheckOutputPacket(int packet, std::vector<float> expected_vector) {
+    const auto& actual_vector =
+        runner_->Outputs().Index(0).packets[packet].Get<std::vector<float>>();
+    EXPECT_THAT(actual_vector, testing::ContainerEq(expected_vector));
+  }
+};
+
+TEST_F(MatrixToVectorCalculatorTest, SingleRow) {
+  InitializeGraph();
+  SetInputHeader(1, 4);  // 1 channel x 4 samples
+  const std::vector<float>& data_vector = {1.0, 2.0, 3.0, 4.0};
+  AppendInput(data_vector, 0);
+  MP_ASSERT_OK(RunGraph());
+  CheckOutputPacket(0, data_vector);
+}
+
+TEST_F(MatrixToVectorCalculatorTest, RegularMatrix) {
+  InitializeGraph();
+  SetInputHeader(4, 2);  // 4 channels x 2 samples
+  // Actual data matrix is the transpose of the appearance below.
+  const std::vector<float>& data_vector = {1.0, 2.0, 3.0, 4.0,
+                                           5.0, 6.0, 7.0, 8.0};
+  AppendInput(data_vector, 0);
+
+  MP_ASSERT_OK(RunGraph());
+  CheckOutputPacket(0, data_vector);
+}
+
+}  // namespace
+
+}  // namespace mediapipe
@@ -78,7 +78,7 @@ TEST(MediaPipeDetectionToSoapboxDetectionCalculatorTest,
  runner.MutableInputs()->Index(1).packets.push_back(
      Adopt(new float(35.5)).At(Timestamp(35)));

-  MEDIAPIPE_ASSERT_OK(runner.Run());
+  MP_ASSERT_OK(runner.Run());

  // Expected combined_output: 5.5, 10, 20, 30, 35.5 at times 5, 10, 20, 30, 35.
  const std::vector<Packet>& actual_output = runner.Outputs().Index(0).packets;
@@ -120,7 +120,7 @@ TEST(MediaPipeDetectionToSoapboxDetectionCalculatorTest,
  runner.MutableInputs()->Index(2).packets.push_back(
      Adopt(new char('c')).At(Timestamp(10)));

-  MEDIAPIPE_ASSERT_OK(runner.Run());
+  MP_ASSERT_OK(runner.Run());

  // Expected combined_output: 'c', 20.5, 30 at times 10, 20, 30.
  const std::vector<Packet>& actual_output = runner.Outputs().Index(0).packets;
@@ -37,7 +37,7 @@ TEST(PacketInnerJoinCalculatorTest, AllMatching) {
  for (int packet_load : packets_on_stream2) {
    runner.MutableInputs()->Index(1).packets.push_back(PacketFrom(packet_load));
  }
-  MEDIAPIPE_ASSERT_OK(runner.Run());
+  MP_ASSERT_OK(runner.Run());
  // Check.
  const std::vector<int> expected = {0, 1, 2, 3};
  ASSERT_EQ(expected.size(), runner.Outputs().Index(0).packets.size());
@@ -64,7 +64,7 @@ TEST(PacketInnerJoinCalculatorTest, NoneMatching) {
  for (int packet_load : packets_on_stream2) {
    runner.MutableInputs()->Index(1).packets.push_back(PacketFrom(packet_load));
  }
-  MEDIAPIPE_ASSERT_OK(runner.Run());
+  MP_ASSERT_OK(runner.Run());
  // Check.
  EXPECT_TRUE(runner.Outputs().Index(0).packets.empty());
  EXPECT_TRUE(runner.Outputs().Index(1).packets.empty());
@@ -82,7 +82,7 @@ TEST(PacketInnerJoinCalculatorTest, SomeMatching) {
  for (int packet_load : packets_on_stream2) {
    runner.MutableInputs()->Index(1).packets.push_back(PacketFrom(packet_load));
  }
-  MEDIAPIPE_ASSERT_OK(runner.Run());
+  MP_ASSERT_OK(runner.Run());
  // Check.
  const std::vector<int> expected = {0, 2, 4, 6};
  ASSERT_EQ(expected.size(), runner.Outputs().Index(0).packets.size());
@@ -12,25 +12,17 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.

-#include <cstdlib>
-#include <memory>
-#include <string>
+#include "mediapipe/calculators/core/packet_resampler_calculator.h"

-#include "absl/strings/str_cat.h"
-#include "mediapipe/calculators/core/packet_resampler_calculator.pb.h"
-#include "mediapipe/framework/calculator_framework.h"
-#include "mediapipe/framework/collection_item_id.h"
-#include "mediapipe/framework/deps/mathutil.h"
-#include "mediapipe/framework/deps/random_base.h"
-#include "mediapipe/framework/formats/video_stream_header.h"
-#include "mediapipe/framework/port/integral_types.h"
-#include "mediapipe/framework/port/logging.h"
-#include "mediapipe/framework/port/ret_check.h"
-#include "mediapipe/framework/port/status.h"
-#include "mediapipe/framework/port/status_macros.h"
-#include "mediapipe/framework/tool/options_util.h"
+#include <memory>

 namespace {
+// Reflect an integer against the lower and upper bound of an interval.
+int64 ReflectBetween(int64 ts, int64 ts_min, int64 ts_max) {
+  if (ts < ts_min) return 2 * ts_min - ts - 1;
+  if (ts >= ts_max) return 2 * ts_max - ts - 1;
+  return ts;
+}

 // Creates a secure random number generator for use in ProcessWithJitter.
 // If no secure random number generator can be constructed, the jitter
@@ -45,114 +37,7 @@ std::unique_ptr<RandomBase> CreateSecureRandom(const std::string& seed) {

 namespace mediapipe {

-// This calculator is used to normalize the frequency of the packets
-// out of a stream. Given a desired frame rate, packets are going to be
-// removed or added to achieve it.
-//
-// The jitter feature is disabled by default. To enable it, you need to
-// implement CreateSecureRandom(const std::string&).
-//
-// The data stream may be either specified as the only stream (by index)
-// or as the stream with tag "DATA".
-//
-// The input and output streams may be accompanied by a VIDEO_HEADER
-// stream.  This stream includes a VideoHeader at Timestamp::PreStream().
-// The input VideoHeader on the VIDEO_HEADER stream will always be updated
-// with the resampler frame rate no matter what the options value for
-// output_header is before being output on the output VIDEO_HEADER stream.
-// If the input VideoHeader is not available, then only the frame rate
-// value will be set in the output.
-//
-// Related:
-//   packet_downsampler_calculator.cc: skips packets regardless of timestamps.
-class PacketResamplerCalculator : public CalculatorBase {
- public:
-  static ::mediapipe::Status GetContract(CalculatorContract* cc);
-
-  ::mediapipe::Status Open(CalculatorContext* cc) override;
-  ::mediapipe::Status Close(CalculatorContext* cc) override;
-  ::mediapipe::Status Process(CalculatorContext* cc) override;
-
- private:
-  // Logic for Process() when jitter_ != 0.0.
-  ::mediapipe::Status ProcessWithJitter(CalculatorContext* cc);
-
-  // Logic for Process() when jitter_ == 0.0.
-  ::mediapipe::Status ProcessWithoutJitter(CalculatorContext* cc);
-
-  // Given the current count of periods that have passed, this returns
-  // the next valid timestamp of the middle point of the next period:
-  //    if count is 0, it returns the first_timestamp_.
-  //    if count is 1, it returns the first_timestamp_ + period (corresponding
-  //       to the first tick using exact fps)
-  // e.g. for frame_rate=30 and first_timestamp_=0:
-  //    0: 0
-  //    1: 33333
-  //    2: 66667
-  //    3: 100000
-  //
-  // Can only be used if jitter_ equals zero.
-  Timestamp PeriodIndexToTimestamp(int64 index) const;
-
-  // Given a Timestamp, finds the closest sync Timestamp based on
-  // first_timestamp_ and the desired fps.
-  //
-  // Can only be used if jitter_ equals zero.
-  int64 TimestampToPeriodIndex(Timestamp timestamp) const;
-
-  // Outputs a packet if it is in range (start_time_, end_time_).
-  void OutputWithinLimits(CalculatorContext* cc, const Packet& packet) const;
-
-  // The timestamp of the first packet received.
-  Timestamp first_timestamp_;
-
-  // Number of frames per second (desired output frequency).
-  double frame_rate_;
-
-  // Inverse of frame_rate_.
-  int64 frame_time_usec_;
-
-  // Number of periods that have passed (= #packets sent to the output).
-  //
-  // Can only be used if jitter_ equals zero.
-  int64 period_count_;
-
-  // The last packet that was received.
-  Packet last_packet_;
-
-  VideoHeader video_header_;
-  // The "DATA" input stream.
-  CollectionItemId input_data_id_;
-  // The "DATA" output stream.
-  CollectionItemId output_data_id_;
-
-  // Indicator whether to flush last packet even if its timestamp is greater
-  // than the final stream timestamp.  Set to false when jitter_ is non-zero.
-  bool flush_last_packet_;
-
-  // Jitter-related variables.
-  std::unique_ptr<RandomBase> random_;
-  double jitter_ = 0.0;
-  Timestamp next_output_timestamp_;
-
-  // If specified, output timestamps are aligned with base_timestamp.
-  // Otherwise, they are aligned with the first input timestamp.
-  Timestamp base_timestamp_;
-
-  // If specified, only outputs at/after start_time are included.
-  Timestamp start_time_;
-
-  // If specified, only outputs before end_time are included.
-  Timestamp end_time_;
-
-  // If set, the output timestamps nearest to start_time and end_time
-  // are included in the output, even if the nearest timestamp is not
-  // between start_time and end_time.
-  bool round_limits_;
-};
-
 REGISTER_CALCULATOR(PacketResamplerCalculator);
-
 namespace {
 // Returns a TimestampDiff (assuming microseconds) corresponding to the
 // given time in seconds.
@@ -203,6 +88,7 @@ TimestampDiff TimestampDiffFromSeconds(double seconds) {

  flush_last_packet_ = resampler_options.flush_last_packet();
  jitter_ = resampler_options.jitter();
+  jitter_with_reflection_ = resampler_options.jitter_with_reflection();

  input_data_id_ = cc->Inputs().GetId("DATA", 0);
  if (!input_data_id_.IsValid()) {
@@ -233,6 +119,9 @@ TimestampDiff TimestampDiffFromSeconds(double seconds) {
      << Timestamp::kTimestampUnitsPerSecond;

  frame_time_usec_ = static_cast<int64>(1000000.0 / frame_rate_);
+  jitter_usec_ = static_cast<int64>(1000000.0 * jitter_ / frame_rate_);
+  RET_CHECK_LE(jitter_usec_, frame_time_usec_);
+
  video_header_.frame_rate = frame_rate_;

  if (resampler_options.output_header() !=
@@ -272,7 +161,10 @@ TimestampDiff TimestampDiffFromSeconds(double seconds) {
          "SecureRandom is not available.  With \"jitter\" specified, "
          "PacketResamplerCalculator processing cannot proceed.");
    }
+    packet_reservoir_random_ = CreateSecureRandom(seed);
  }
+  packet_reservoir_ =
+      std::make_unique<PacketReservoir>(packet_reservoir_random_.get());
  return ::mediapipe::OkStatus();
 }

@@ -287,14 +179,56 @@ TimestampDiff TimestampDiffFromSeconds(double seconds) {
    }
  }
  if (jitter_ != 0.0 && random_ != nullptr) {
-    RETURN_IF_ERROR(ProcessWithJitter(cc));
+    // Packet reservior is used to make sure there's an output for every period,
+    // e.g. partial period at the end of the stream.
+    if (packet_reservoir_->IsEnabled() &&
+        (first_timestamp_ == Timestamp::Unset() ||
+         (cc->InputTimestamp() - next_output_timestamp_min_).Value() >= 0)) {
+      auto curr_packet = cc->Inputs().Get(input_data_id_).Value();
+      packet_reservoir_->AddSample(curr_packet);
+    }
+    MP_RETURN_IF_ERROR(ProcessWithJitter(cc));
  } else {
-    RETURN_IF_ERROR(ProcessWithoutJitter(cc));
+    MP_RETURN_IF_ERROR(ProcessWithoutJitter(cc));
  }
  last_packet_ = cc->Inputs().Get(input_data_id_).Value();
  return ::mediapipe::OkStatus();
 }

+void PacketResamplerCalculator::InitializeNextOutputTimestampWithJitter() {
+  next_output_timestamp_min_ = first_timestamp_;
+  if (jitter_with_reflection_) {
+    next_output_timestamp_ =
+        first_timestamp_ + random_->UnbiasedUniform64(frame_time_usec_);
+    return;
+  }
+  next_output_timestamp_ =
+      first_timestamp_ + frame_time_usec_ * random_->RandFloat();
+}
+
+void PacketResamplerCalculator::UpdateNextOutputTimestampWithJitter() {
+  packet_reservoir_->Clear();
+  if (jitter_with_reflection_) {
+    next_output_timestamp_min_ += frame_time_usec_;
+    Timestamp next_output_timestamp_max_ =
+        next_output_timestamp_min_ + frame_time_usec_;
+
+    next_output_timestamp_ += frame_time_usec_ +
+                              random_->UnbiasedUniform64(2 * jitter_usec_ + 1) -
+                              jitter_usec_;
+    next_output_timestamp_ = Timestamp(ReflectBetween(
+        next_output_timestamp_.Value(), next_output_timestamp_min_.Value(),
+        next_output_timestamp_max_.Value()));
+    CHECK_GE(next_output_timestamp_, next_output_timestamp_min_);
+    CHECK_LT(next_output_timestamp_, next_output_timestamp_max_);
+    return;
+  }
+  packet_reservoir_->Disable();
+  next_output_timestamp_ +=
+      frame_time_usec_ *
+      ((1.0 - jitter_) + 2.0 * jitter_ * random_->RandFloat());
+}
+
 ::mediapipe::Status PacketResamplerCalculator::ProcessWithJitter(
    CalculatorContext* cc) {
  RET_CHECK_GT(cc->InputTimestamp(), Timestamp::PreStream());
@@ -302,29 +236,37 @@ TimestampDiff TimestampDiffFromSeconds(double seconds) {

  if (first_timestamp_ == Timestamp::Unset()) {
    first_timestamp_ = cc->InputTimestamp();
-    next_output_timestamp_ =
-        first_timestamp_ + frame_time_usec_ * random_->RandFloat();
+    InitializeNextOutputTimestampWithJitter();
+    if (first_timestamp_ == next_output_timestamp_) {
+      OutputWithinLimits(
+          cc,
+          cc->Inputs().Get(input_data_id_).Value().At(next_output_timestamp_));
+      UpdateNextOutputTimestampWithJitter();
+    }
    return ::mediapipe::OkStatus();
  }

-  LOG_IF(WARNING, frame_time_usec_ <
-                      (cc->InputTimestamp() - last_packet_.Timestamp()).Value())
-      << "Adding jitter is meaningless when upsampling.";
+  if (frame_time_usec_ <
+      (cc->InputTimestamp() - last_packet_.Timestamp()).Value()) {
+    LOG_FIRST_N(WARNING, 2)
+        << "Adding jitter is not very useful when upsampling.";
+  }

-  const int64 curr_diff =
-      (next_output_timestamp_ - cc->InputTimestamp()).Value();
-  const int64 last_diff =
-      (next_output_timestamp_ - last_packet_.Timestamp()).Value();
-  if (curr_diff * last_diff > 0) {
-    return ::mediapipe::OkStatus();
+  while (true) {
+    const int64 last_diff =
+        (next_output_timestamp_ - last_packet_.Timestamp()).Value();
+    RET_CHECK_GT(last_diff, 0);
+    const int64 curr_diff =
+        (next_output_timestamp_ - cc->InputTimestamp()).Value();
+    if (curr_diff > 0) {
+      break;
+    }
+    OutputWithinLimits(cc, (std::abs(curr_diff) > last_diff
+                                ? last_packet_
+                                : cc->Inputs().Get(input_data_id_).Value())
+                               .At(next_output_timestamp_));
+    UpdateNextOutputTimestampWithJitter();
  }
-  OutputWithinLimits(cc, (std::abs(curr_diff) > std::abs(last_diff)
-                              ? last_packet_
-                              : cc->Inputs().Get(input_data_id_).Value())
-                             .At(next_output_timestamp_));
-  next_output_timestamp_ +=
-      frame_time_usec_ *
-      ((1.0 - jitter_) + 2.0 * jitter_ * random_->RandFloat());
  return ::mediapipe::OkStatus();
 }

@@ -405,6 +347,9 @@ TimestampDiff TimestampDiffFromSeconds(double seconds) {
    OutputWithinLimits(cc,
                       last_packet_.At(PeriodIndexToTimestamp(period_count_)));
  }
+  if (!packet_reservoir_->IsEmpty()) {
+    OutputWithinLimits(cc, packet_reservoir_->GetSample());
+  }
  return ::mediapipe::OkStatus();
 }

@@ -0,0 +1,205 @@
+#ifndef MEDIAPIPE_CALCULATORS_CORE_PACKET_RESAMPLER_CALCULATOR_H_
+#define MEDIAPIPE_CALCULATORS_CORE_PACKET_RESAMPLER_CALCULATOR_H_
+
+#include <cstdlib>
+#include <memory>
+#include <string>
+
+#include "absl/strings/str_cat.h"
+#include "mediapipe/calculators/core/packet_resampler_calculator.pb.h"
+#include "mediapipe/framework/calculator_framework.h"
+#include "mediapipe/framework/collection_item_id.h"
+#include "mediapipe/framework/deps/mathutil.h"
+#include "mediapipe/framework/deps/random_base.h"
+#include "mediapipe/framework/formats/video_stream_header.h"
+#include "mediapipe/framework/port/integral_types.h"
+#include "mediapipe/framework/port/logging.h"
+#include "mediapipe/framework/port/ret_check.h"
+#include "mediapipe/framework/port/status.h"
+#include "mediapipe/framework/port/status_macros.h"
+#include "mediapipe/framework/tool/options_util.h"
+
+namespace mediapipe {
+
+class PacketReservoir {
+ public:
+  PacketReservoir(RandomBase* rng) : rng_(rng) {}
+  // Replace candidate with current packet with 1/count_ probability.
+  void AddSample(Packet sample) {
+    if (rng_->UnbiasedUniform(++count_) == 0) {
+      reservoir_ = sample;
+    }
+  }
+  bool IsEnabled() { return rng_ && enabled_; }
+  void Disable() {
+    if (enabled_) enabled_ = false;
+  }
+  void Clear() { count_ = 0; }
+  bool IsEmpty() { return count_ == 0; }
+  Packet GetSample() { return reservoir_; }
+
+ private:
+  RandomBase* rng_;
+  bool enabled_ = true;
+  int32 count_ = 0;
+  Packet reservoir_;
+};
+
+// This calculator is used to normalize the frequency of the packets
+// out of a stream. Given a desired frame rate, packets are going to be
+// removed or added to achieve it.
+//
+// If jitter_ is specified:
+//   - The first packet is chosen randomly (uniform distribution) among frames
+//     that correspond to timestamps [0, 1/frame_rate).  Let the chosen packet
+//     correspond to timestamp t.
+//   - The next packet is chosen randomly (uniform distribution) among frames
+//     that correspond to [t+(1-jitter)/frame_rate, t+(1+jitter)/frame_rate].
+//     - if jitter_with_reflection_ is true, the timestamp will be reflected
+//       against the boundaries of [t_0 + (k-1)/frame_rate, t_0 + k/frame_rate)
+//       so that its marginal distribution is uniform within this interval.
+//       In the formula, t_0 is the timestamp of the first sampled
+//       packet, and the k is the packet index.
+//       See paper (https://arxiv.org/abs/2002.01147) for details.
+//   - t is updated and the process is repeated.
+//   - Note that seed is specified as input side packet for reproducibility of
+//     the resampling.  For Cloud ML Video Intelligence API, the hash of the
+//     input video should serve this purpose.  For YouTube, either video ID or
+//     content hex ID of the input video should do.
+//
+// If jitter_ is not specified:
+//   - The first packet defines the first_timestamp of the output stream,
+//     so it is always emitted.
+//   - If more packets are emitted, they will have timestamp equal to
+//     round(first_timestamp + k * period) , where k is a positive
+//     integer and the period is defined by the frame rate.
+//     Example: first_timestamp=0, fps=30, then the output stream
+//              will have timestamps: 0, 33333, 66667, 100000, etc...
+//   - The packets selected for the output stream are the ones closer
+//     to the exact middle point (33333.33, 66666.67 in our previous
+//     example). In case of ties, later packets are chosen.
+//   - 'Empty' periods happen when there are no packets for a long time
+//     (greater than a period). In this case, we send a copy of the last
+//     packet received before the empty period.
+// The jitter feature is disabled by default. To enable it, you need to
+// implement CreateSecureRandom(const std::string&).
+//
+// The data stream may be either specified as the only stream (by index)
+// or as the stream with tag "DATA".
+//
+// The input and output streams may be accompanied by a VIDEO_HEADER
+// stream.  This stream includes a VideoHeader at Timestamp::PreStream().
+// The input VideoHeader on the VIDEO_HEADER stream will always be updated
+// with the resampler frame rate no matter what the options value for
+// output_header is before being output on the output VIDEO_HEADER stream.
+// If the input VideoHeader is not available, then only the frame rate
+// value will be set in the output.
+//
+// Related:
+//   packet_downsampler_calculator.cc: skips packets regardless of timestamps.
+class PacketResamplerCalculator : public CalculatorBase {
+ public:
+  static ::mediapipe::Status GetContract(CalculatorContract* cc);
+
+  ::mediapipe::Status Open(CalculatorContext* cc) override;
+  ::mediapipe::Status Close(CalculatorContext* cc) override;
+  ::mediapipe::Status Process(CalculatorContext* cc) override;
+
+ private:
+  // Calculates the first sampled timestamp that incorporates a jittering
+  // offset.
+  void InitializeNextOutputTimestampWithJitter();
+  // Calculates the next sampled timestamp that incorporates a jittering offset.
+  void UpdateNextOutputTimestampWithJitter();
+
+  // Logic for Process() when jitter_ != 0.0.
+  ::mediapipe::Status ProcessWithJitter(CalculatorContext* cc);
+
+  // Logic for Process() when jitter_ == 0.0.
+  ::mediapipe::Status ProcessWithoutJitter(CalculatorContext* cc);
+
+  // Given the current count of periods that have passed, this returns
+  // the next valid timestamp of the middle point of the next period:
+  //    if count is 0, it returns the first_timestamp_.
+  //    if count is 1, it returns the first_timestamp_ + period (corresponding
+  //       to the first tick using exact fps)
+  // e.g. for frame_rate=30 and first_timestamp_=0:
+  //    0: 0
+  //    1: 33333
+  //    2: 66667
+  //    3: 100000
+  //
+  // Can only be used if jitter_ equals zero.
+  Timestamp PeriodIndexToTimestamp(int64 index) const;
+
+  // Given a Timestamp, finds the closest sync Timestamp based on
+  // first_timestamp_ and the desired fps.
+  //
+  // Can only be used if jitter_ equals zero.
+  int64 TimestampToPeriodIndex(Timestamp timestamp) const;
+
+  // Outputs a packet if it is in range (start_time_, end_time_).
+  void OutputWithinLimits(CalculatorContext* cc, const Packet& packet) const;
+
+  // The timestamp of the first packet received.
+  Timestamp first_timestamp_;
+
+  // Number of frames per second (desired output frequency).
+  double frame_rate_;
+
+  // Inverse of frame_rate_.
+  int64 frame_time_usec_;
+
+  // Number of periods that have passed (= #packets sent to the output).
+  //
+  // Can only be used if jitter_ equals zero.
+  int64 period_count_;
+
+  // The last packet that was received.
+  Packet last_packet_;
+
+  VideoHeader video_header_;
+  // The "DATA" input stream.
+  CollectionItemId input_data_id_;
+  // The "DATA" output stream.
+  CollectionItemId output_data_id_;
+
+  // Indicator whether to flush last packet even if its timestamp is greater
+  // than the final stream timestamp.  Set to false when jitter_ is non-zero.
+  bool flush_last_packet_;
+
+  // Jitter-related variables.
+  std::unique_ptr<RandomBase> random_;
+  double jitter_ = 0.0;
+  bool jitter_with_reflection_;
+  int64 jitter_usec_;
+  Timestamp next_output_timestamp_;
+  // If jittering_with_reflection_ is true, next_output_timestamp_ will be
+  // kept within the interval
+  // [next_output_timestamp_min_, next_output_timestamp_min_ + frame_time_usec_)
+  Timestamp next_output_timestamp_min_;
+
+  // If specified, output timestamps are aligned with base_timestamp.
+  // Otherwise, they are aligned with the first input timestamp.
+  Timestamp base_timestamp_;
+
+  // If specified, only outputs at/after start_time are included.
+  Timestamp start_time_;
+
+  // If specified, only outputs before end_time are included.
+  Timestamp end_time_;
+
+  // If set, the output timestamps nearest to start_time and end_time
+  // are included in the output, even if the nearest timestamp is not
+  // between start_time and end_time.W
+  bool round_limits_;
+
+  // packet reservior used for sampling random packet out of partial
+  // period when jitter is enabled
+  std::unique_ptr<PacketReservoir> packet_reservoir_;
+  // random number generator used in packet_reservior_.
+  std::unique_ptr<RandomBase> packet_reservoir_random_;
+};
+
+}  // namespace mediapipe
+#endif  // MEDIAPIPE_CALCULATORS_CORE_PACKET_RESAMPLER_CALCULATOR_H_
@@ -66,6 +66,7 @@ message PacketResamplerCalculatorOptions {
  // pseudo-random number generator does its job and the number of frames is
  // sufficiently large, the average frame rate will be close to this value.
  optional double jitter = 4;
+  optional bool jitter_with_reflection = 9 [default = false];

  // If specified, output timestamps are aligned with base_timestamp.
  // Otherwise, they are aligned with the first input timestamp.
@@ -12,6 +12,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.

+#include "mediapipe/calculators/core/packet_resampler_calculator.h"
+
 #include <memory>
 #include <string>
 #include <vector>
@@ -29,7 +31,6 @@
 namespace mediapipe {

 namespace {
-
 // A simple version of CalculatorRunner with built-in convenience
 // methods for setting inputs from a vector and checking outputs
 // against expected outputs (both timestamps and contents).
@@ -103,7 +104,7 @@ TEST(PacketResamplerCalculatorTest, NoPacketsInStream) {
        "[mediapipe.PacketResamplerCalculatorOptions.ext]: "
        "{frame_rate:30}");
    runner.SetInput({});
-    MEDIAPIPE_ASSERT_OK(runner.Run());
+    MP_ASSERT_OK(runner.Run());
  }
 }

@@ -114,7 +115,7 @@ TEST(PacketResamplerCalculatorTest, SinglePacketInStream) {
        "[mediapipe.PacketResamplerCalculatorOptions.ext]: "
        "{frame_rate:30}");
    runner.SetInput({0});
-    MEDIAPIPE_ASSERT_OK(runner.Run());
+    MP_ASSERT_OK(runner.Run());
    runner.CheckOutputTimestamps({0}, {0});
  }

@@ -124,7 +125,7 @@ TEST(PacketResamplerCalculatorTest, SinglePacketInStream) {
        "[mediapipe.PacketResamplerCalculatorOptions.ext]: "
        "{frame_rate:30}");
    runner.SetInput({1000});
-    MEDIAPIPE_ASSERT_OK(runner.Run());
+    MP_ASSERT_OK(runner.Run());
    runner.CheckOutputTimestamps({1000}, {1000});
  }

@@ -134,7 +135,7 @@ TEST(PacketResamplerCalculatorTest, SinglePacketInStream) {
        "[mediapipe.PacketResamplerCalculatorOptions.ext]: "
        "{frame_rate:30}");
    runner.SetInput({16668});
-    MEDIAPIPE_ASSERT_OK(runner.Run());
+    MP_ASSERT_OK(runner.Run());
    runner.CheckOutputTimestamps({16668}, {16668});
  }
 }
@@ -146,7 +147,7 @@ TEST(PacketResamplerCalculatorTest, TwoPacketsInStream) {
        "[mediapipe.PacketResamplerCalculatorOptions.ext]: "
        "{frame_rate:30}");
    runner.SetInput({0, 16666});
-    MEDIAPIPE_ASSERT_OK(runner.Run());
+    MP_ASSERT_OK(runner.Run());
    runner.CheckOutputTimestamps({0}, {0});
  }

@@ -156,7 +157,7 @@ TEST(PacketResamplerCalculatorTest, TwoPacketsInStream) {
        "[mediapipe.PacketResamplerCalculatorOptions.ext]: "
        "{frame_rate:30}");
    runner.SetInput({0, 16667});
-    MEDIAPIPE_ASSERT_OK(runner.Run());
+    MP_ASSERT_OK(runner.Run());
    runner.CheckOutputTimestamps({0, 16667}, {0, 33333});
  }

@@ -166,7 +167,7 @@ TEST(PacketResamplerCalculatorTest, TwoPacketsInStream) {
        "[mediapipe.PacketResamplerCalculatorOptions.ext]: "
        "{frame_rate:30}");
    runner.SetInput({0, 49999});
-    MEDIAPIPE_ASSERT_OK(runner.Run());
+    MP_ASSERT_OK(runner.Run());
    runner.CheckOutputTimestamps({0, 49999}, {0, 33333});
  }

@@ -176,7 +177,7 @@ TEST(PacketResamplerCalculatorTest, TwoPacketsInStream) {
        "[mediapipe.PacketResamplerCalculatorOptions.ext]: "
        "{frame_rate:30}");
    runner.SetInput({0, 50000});
-    MEDIAPIPE_ASSERT_OK(runner.Run());
+    MP_ASSERT_OK(runner.Run());
    runner.CheckOutputTimestamps({0, 0, 50000}, {0, 33333, 66667});
  }

@@ -186,7 +187,7 @@ TEST(PacketResamplerCalculatorTest, TwoPacketsInStream) {
        "[mediapipe.PacketResamplerCalculatorOptions.ext]: "
        "{frame_rate:30}");
    runner.SetInput({2000, 118666});
-    MEDIAPIPE_ASSERT_OK(runner.Run());
+    MP_ASSERT_OK(runner.Run());
    runner.CheckOutputTimestamps({2000, 2000, 2000, 118666},
                                 {2000, 35333, 68667, 102000});
  }
@@ -197,7 +198,7 @@ TEST(PacketResamplerCalculatorTest, InputAtExactFrequencyMiddlepoints) {
      "[mediapipe.PacketResamplerCalculatorOptions.ext]: "
      "{frame_rate:30}");
  runner.SetInput({0, 33333, 66667, 100000, 133333, 166667, 200000});
-  MEDIAPIPE_ASSERT_OK(runner.Run());
+  MP_ASSERT_OK(runner.Run());
  runner.CheckOutputTimestamps(
      {0, 33333, 66667, 100000, 133333, 166667, 200000},
      {0, 33333, 66667, 100000, 133333, 166667, 200000});
@@ -210,7 +211,7 @@ TEST(PacketResamplerCalculatorTest, MultiplePacketsForPeriods) {
      "[mediapipe.PacketResamplerCalculatorOptions.ext]: "
      "{frame_rate:30}");
  runner.SetInput({0, 16666, 16667, 20000, 33300, 49999, 50000, 66600});
-  MEDIAPIPE_ASSERT_OK(runner.Run());
+  MP_ASSERT_OK(runner.Run());
  runner.CheckOutputTimestamps({0, 33300, 66600}, {0, 33333, 66667});
 }

@@ -222,7 +223,7 @@ TEST(PacketResamplerCalculatorTest, FillPeriodsWithLatestPacket) {
        "[mediapipe.PacketResamplerCalculatorOptions.ext]: "
        "{frame_rate:30}");
    runner.SetInput({0, 5000, 16666, 83334});
-    MEDIAPIPE_ASSERT_OK(runner.Run());
+    MP_ASSERT_OK(runner.Run());
    runner.CheckOutputTimestamps({0, 16666, 16666, 83334},
                                 {0, 33333, 66667, 100000});
  }
@@ -232,7 +233,7 @@ TEST(PacketResamplerCalculatorTest, FillPeriodsWithLatestPacket) {
        "[mediapipe.PacketResamplerCalculatorOptions.ext]: "
        "{frame_rate:30}");
    runner.SetInput({0, 16666, 16667, 25000, 33000, 35000, 135000});
-    MEDIAPIPE_ASSERT_OK(runner.Run());
+    MP_ASSERT_OK(runner.Run());
    runner.CheckOutputTimestamps({0, 33000, 35000, 35000, 135000},
                                 {0, 33333, 66667, 100000, 133333});
  }
@@ -242,7 +243,7 @@ TEST(PacketResamplerCalculatorTest, FillPeriodsWithLatestPacket) {
        "[mediapipe.PacketResamplerCalculatorOptions.ext]: "
        "{frame_rate:30}");
    runner.SetInput({0, 15000, 32000, 49999, 150000});
-    MEDIAPIPE_ASSERT_OK(runner.Run());
+    MP_ASSERT_OK(runner.Run());
    runner.CheckOutputTimestamps({0, 32000, 49999, 49999, 49999, 150000},
                                 {0, 33333, 66667, 100000, 133333, 166667});
  }
@@ -255,7 +256,7 @@ TEST(PacketResamplerCalculatorTest, SuperHighFrameRate) {
        "[mediapipe.PacketResamplerCalculatorOptions.ext]: "
        "{frame_rate:500000}");
    runner.SetInput({0, 10, 13});
-    MEDIAPIPE_ASSERT_OK(runner.Run());
+    MP_ASSERT_OK(runner.Run());
    runner.CheckOutputTimestamps({0, 0, 0, 0, 0, 10, 10, 13},
                                 {0, 2, 4, 6, 8, 10, 12, 14});
  }
@@ -266,7 +267,7 @@ TEST(PacketResamplerCalculatorTest, SuperHighFrameRate) {
        "[mediapipe.PacketResamplerCalculatorOptions.ext]: "
        "{frame_rate:1000000}");
    runner.SetInput({0, 10, 13});
-    MEDIAPIPE_ASSERT_OK(runner.Run());
+    MP_ASSERT_OK(runner.Run());
    runner.CheckOutputTimestamps(
        {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 10, 10, 10, 13},
        {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13});
@@ -280,7 +281,7 @@ TEST(PacketResamplerCalculatorTest, NegativeTimestampTest) {
        "[mediapipe.PacketResamplerCalculatorOptions.ext]: "
        "{frame_rate:30}");
    runner.SetInput({-200, -20, 16466});
-    MEDIAPIPE_ASSERT_OK(runner.Run());
+    MP_ASSERT_OK(runner.Run());
    runner.CheckOutputTimestamps({-200}, {-200});
  }

@@ -290,7 +291,7 @@ TEST(PacketResamplerCalculatorTest, NegativeTimestampTest) {
        "[mediapipe.PacketResamplerCalculatorOptions.ext]: "
        "{frame_rate:30}");
    runner.SetInput({-200, -20, 16467});
-    MEDIAPIPE_ASSERT_OK(runner.Run());
+    MP_ASSERT_OK(runner.Run());
    runner.CheckOutputTimestamps({-200, 16467}, {-200, 33133});
  }

@@ -300,7 +301,7 @@ TEST(PacketResamplerCalculatorTest, NegativeTimestampTest) {
        "[mediapipe.PacketResamplerCalculatorOptions.ext]: "
        "{frame_rate:30}");
    runner.SetInput({-500, 66667});
-    MEDIAPIPE_ASSERT_OK(runner.Run());
+    MP_ASSERT_OK(runner.Run());
    runner.CheckOutputTimestamps({-500, -500, 66667}, {-500, 32833, 66167});
  }

@@ -310,7 +311,7 @@ TEST(PacketResamplerCalculatorTest, NegativeTimestampTest) {
        "[mediapipe.PacketResamplerCalculatorOptions.ext]: "
        "{frame_rate:30}");
    runner.SetInput({-50000, -33334, 33334});
-    MEDIAPIPE_ASSERT_OK(runner.Run());
+    MP_ASSERT_OK(runner.Run());
    runner.CheckOutputTimestamps({-50000, -33334, -33334, 33334},
                                 {-50000, -16667, 16667, 50000});
  }
@@ -323,7 +324,7 @@ TEST(PacketResamplerCalculatorTest, ExactFramesPerSecond) {
        "[mediapipe.PacketResamplerCalculatorOptions.ext]: "
        "{frame_rate:50}");
    runner.SetInput({0, 9999, 29999});
-    MEDIAPIPE_ASSERT_OK(runner.Run());
+    MP_ASSERT_OK(runner.Run());
    runner.CheckOutputTimestamps({0, 29999}, {0, 20000});
  }

@@ -333,7 +334,7 @@ TEST(PacketResamplerCalculatorTest, ExactFramesPerSecond) {
        "[mediapipe.PacketResamplerCalculatorOptions.ext]: "
        "{frame_rate:50}");
    runner.SetInput({0, 10000, 50000});
-    MEDIAPIPE_ASSERT_OK(runner.Run());
+    MP_ASSERT_OK(runner.Run());
    runner.CheckOutputTimestamps({0, 10000, 10000, 50000},
                                 {0, 20000, 40000, 60000});
  }
@@ -347,7 +348,7 @@ TEST(PacketResamplerCalculatorTest, FrameRateTest) {
        "{frame_rate:50, output_header:UPDATE_VIDEO_HEADER}");
    runner.SetInput({0, 10000, 30000, 50000, 60000});
    runner.SetVideoHeader(50.0);
-    MEDIAPIPE_ASSERT_OK(runner.Run());
+    MP_ASSERT_OK(runner.Run());
    runner.CheckOutputTimestamps({0, 10000, 30000, 60000},
                                 {0, 20000, 40000, 60000});
    runner.CheckVideoHeader(50.0);
@@ -360,7 +361,7 @@ TEST(PacketResamplerCalculatorTest, FrameRateTest) {
        "{frame_rate:50, output_header:UPDATE_VIDEO_HEADER}");
    runner.SetInput({0, 5000, 10010, 15001, 19990});
    runner.SetVideoHeader(200.0);
-    MEDIAPIPE_ASSERT_OK(runner.Run());
+    MP_ASSERT_OK(runner.Run());
    runner.CheckOutputTimestamps({0, 19990}, {0, 20000});
    runner.CheckVideoHeader(50.0);
  }
@@ -372,7 +373,7 @@ TEST(PacketResamplerCalculatorTest, FrameRateTest) {
        "{frame_rate:50, output_header:PASS_HEADER}");
    runner.SetInput({0, 5000, 10010, 15001, 19990});
    runner.SetVideoHeader(200.0);
-    MEDIAPIPE_ASSERT_OK(runner.Run());
+    MP_ASSERT_OK(runner.Run());
    runner.CheckOutputTimestamps({0, 19990}, {0, 20000});
    runner.CheckVideoHeader(200.0);
  }
@@ -404,7 +405,7 @@ TEST(PacketResamplerCalculatorTest, SetVideoHeader) {
      ->Tag("VIDEO_HEADER")
      .packets.push_back(
          Adopt(new VideoHeader(video_header_in)).At(Timestamp::PreStream()));
-  MEDIAPIPE_ASSERT_OK(runner.Run());
+  MP_ASSERT_OK(runner.Run());

  ASSERT_EQ(1, runner.Outputs().Tag("VIDEO_HEADER").packets.size());
  EXPECT_EQ(Timestamp::PreStream(),
@@ -424,7 +425,7 @@ TEST(PacketResamplerCalculatorTest, FlushLastPacketWithoutRound) {
        frame_rate: 1
      })");
  runner.SetInput({0, 333333, 666667, 1000000, 1333333});
-  MEDIAPIPE_ASSERT_OK(runner.Run());
+  MP_ASSERT_OK(runner.Run());
  // 1333333 is not emitted as 2000000, because it does not round to 2000000.
  runner.CheckOutputTimestamps({0, 1000000}, {0, 1000000});
 }
@@ -435,7 +436,7 @@ TEST(PacketResamplerCalculatorTest, FlushLastPacketWithRound) {
        frame_rate: 1
      })");
  runner.SetInput({0, 333333, 666667, 1000000, 1333333, 1666667});
-  MEDIAPIPE_ASSERT_OK(runner.Run());
+  MP_ASSERT_OK(runner.Run());
  // 1666667 is emitted as 2000000, because it rounds to 2000000.
  runner.CheckOutputTimestamps({0, 1000000, 1666667}, {0, 1000000, 2000000});
 }
@@ -447,7 +448,7 @@ TEST(PacketResamplerCalculatorTest, DoNotFlushLastPacketWithoutRound) {
        flush_last_packet: false
      })");
  runner.SetInput({0, 333333, 666667, 1000000, 1333333});
-  MEDIAPIPE_ASSERT_OK(runner.Run());
+  MP_ASSERT_OK(runner.Run());
  // 1333333 is not emitted no matter what; see FlushLastPacketWithoutRound.
  runner.CheckOutputTimestamps({0, 1000000}, {0, 1000000});
 }
@@ -459,7 +460,7 @@ TEST(PacketResamplerCalculatorTest, DoNotFlushLastPacketWithRound) {
        flush_last_packet: false
      })");
  runner.SetInput({0, 333333, 666667, 1000000, 1333333, 1666667});
-  MEDIAPIPE_ASSERT_OK(runner.Run());
+  MP_ASSERT_OK(runner.Run());
  // 1666667 is not emitted due to flush_last_packet: false.
  runner.CheckOutputTimestamps({0, 1000000}, {0, 1000000});
 }
@@ -473,7 +474,7 @@ TEST(PacketResamplerCalculatorTest, InputAtExactFrequencyMiddlepointsAligned) {
        "[mediapipe.PacketResamplerCalculatorOptions.ext]: "
        "{frame_rate:30}");
    runner.SetInput({33111, 66667, 100000, 133333, 166667, 200000});
-    MEDIAPIPE_ASSERT_OK(runner.Run());
+    MP_ASSERT_OK(runner.Run());
    runner.CheckOutputTimestamps({33111, 66667, 100000, 133333, 166667, 200000},
                                 {33111, 66444, 99778, 133111, 166444, 199778});
  }
@@ -484,7 +485,7 @@ TEST(PacketResamplerCalculatorTest, InputAtExactFrequencyMiddlepointsAligned) {
        "{frame_rate:30 "
        "base_timestamp:0}");
    runner.SetInput({33111, 66667, 100000, 133333, 166667, 200000});
-    MEDIAPIPE_ASSERT_OK(runner.Run());
+    MP_ASSERT_OK(runner.Run());
    runner.CheckOutputTimestamps(
        {33111, 66667, 100000, 133333, 166667, 200000},
        {33333, 66666, 100000, 133333, 166666, 200000});
@@ -499,7 +500,7 @@ TEST(PacketResamplerCalculatorTest, MultiplePacketsForPeriodsAligned) {
        "[mediapipe.PacketResamplerCalculatorOptions.ext]: "
        "{frame_rate:30}");
    runner.SetInput({-222, 16666, 16667, 20000, 33300, 49999, 50000, 66600});
-    MEDIAPIPE_ASSERT_OK(runner.Run());
+    MP_ASSERT_OK(runner.Run());
    runner.CheckOutputTimestamps({-222, 33300, 66600}, {-222, 33111, 66445});
  }
  {
@@ -509,7 +510,7 @@ TEST(PacketResamplerCalculatorTest, MultiplePacketsForPeriodsAligned) {
        "{frame_rate:30 "
        "base_timestamp:900011}");
    runner.SetInput({-222, 16666, 16667, 20000, 33300, 49999, 50000, 66600});
-    MEDIAPIPE_ASSERT_OK(runner.Run());
+    MP_ASSERT_OK(runner.Run());
    runner.CheckOutputTimestamps({-222, 33300, 66600}, {11, 33344, 66678});
  }
  {
@@ -521,7 +522,7 @@ TEST(PacketResamplerCalculatorTest, MultiplePacketsForPeriodsAligned) {
        "base_timestamp:11}");
    runner.SetInput(
        {899888, 916666, 916667, 920000, 933300, 949999, 950000, 966600});
-    MEDIAPIPE_ASSERT_OK(runner.Run());
+    MP_ASSERT_OK(runner.Run());
    runner.CheckOutputTimestamps({899888, 933300, 966600},
                                 {900011, 933344, 966678});
  }
@@ -536,7 +537,7 @@ TEST(PacketResamplerCalculatorTest, FillPeriodsWithLatestPacketAligned) {
        "[mediapipe.PacketResamplerCalculatorOptions.ext]: "
        "{frame_rate:30}");
    runner.SetInput({-222, 15000, 32000, 49999, 150000});
-    MEDIAPIPE_ASSERT_OK(runner.Run());
+    MP_ASSERT_OK(runner.Run());
    runner.CheckOutputTimestamps({-222, 32000, 49999, 49999, 49999, 150000},
                                 {-222, 33111, 66445, 99778, 133111, 166445});
  }
@@ -547,7 +548,7 @@ TEST(PacketResamplerCalculatorTest, FillPeriodsWithLatestPacketAligned) {
        "{frame_rate:30 "
        "base_timestamp:0}");
    runner.SetInput({-222, 15000, 32000, 49999, 150000});
-    MEDIAPIPE_ASSERT_OK(runner.Run());
+    MP_ASSERT_OK(runner.Run());
    runner.CheckOutputTimestamps({-222, 32000, 49999, 49999, 49999, 150000},
                                 {0, 33333, 66667, 100000, 133333, 166667});
  }
@@ -565,7 +566,7 @@ TEST(PacketResamplerCalculatorTest, FirstInputAfterMiddlepointAligned) {
        "{frame_rate:30 "
        "base_timestamp:0}");
    runner.SetInput({66667, 100020, 133333, 166667});
-    MEDIAPIPE_ASSERT_OK(runner.Run());
+    MP_ASSERT_OK(runner.Run());
    runner.CheckOutputTimestamps({66667, 100020, 133333, 166667},
                                 {66667, 100000, 133334, 166667});
  }
@@ -582,7 +583,7 @@ TEST(PacketResamplerCalculatorTest, FirstInputAfterMiddlepointAligned) {
        "{frame_rate:30 "
        "base_timestamp:0}");
    runner.SetInput({100020, 133333, 166667});
-    MEDIAPIPE_ASSERT_OK(runner.Run());
+    MP_ASSERT_OK(runner.Run());
    runner.CheckOutputTimestamps({100020, 133333, 166667},
                                 {100000, 133333, 166667});
  }
@@ -596,7 +597,7 @@ TEST(PacketResamplerCalculatorTest, OutputTimestampRangeAligned) {
        "{frame_rate:30 "
        "base_timestamp:0}");
    runner.SetInput({-222, 15000, 32000, 49999, 150000});
-    MEDIAPIPE_ASSERT_OK(runner.Run());
+    MP_ASSERT_OK(runner.Run());
    runner.CheckOutputTimestamps({-222, 32000, 49999, 49999, 49999, 150000},
                                 {0, 33333, 66667, 100000, 133333, 166667});
  }
@@ -609,7 +610,7 @@ TEST(PacketResamplerCalculatorTest, OutputTimestampRangeAligned) {
        "start_time:40000 "
        "end_time:160000}");
    runner.SetInput({-222, 15000, 32000, 49999, 150000});
-    MEDIAPIPE_ASSERT_OK(runner.Run());
+    MP_ASSERT_OK(runner.Run());
    runner.CheckOutputTimestamps({49999, 49999, 49999},
                                 {66667, 100000, 133333});
  }
@@ -624,7 +625,7 @@ TEST(PacketResamplerCalculatorTest, OutputTimestampRangeAligned) {
        "end_time:160000 "
        "round_limits:true}");
    runner.SetInput({-222, 15000, 32000, 49999, 150000});
-    MEDIAPIPE_ASSERT_OK(runner.Run());
+    MP_ASSERT_OK(runner.Run());
    runner.CheckOutputTimestamps({32000, 49999, 49999, 49999, 150000},
                                 {33333, 66667, 100000, 133333, 166667});
  }
@@ -654,7 +655,7 @@ TEST(PacketResamplerCalculatorTest, OptionsSidePacket) {
              })"));
    runner.MutableSidePackets()->Tag("OPTIONS") = Adopt(options);
    runner.SetInput({-222, 15000, 32000, 49999, 150000});
-    MEDIAPIPE_ASSERT_OK(runner.Run());
+    MP_ASSERT_OK(runner.Run());
    EXPECT_EQ(6, runner.Outputs().Index(0).packets.size());
  }
  {
@@ -670,7 +671,7 @@ TEST(PacketResamplerCalculatorTest, OptionsSidePacket) {
    runner.MutableSidePackets()->Tag("OPTIONS") = Adopt(options);

    runner.SetInput({-222, 15000, 32000, 49999, 150000});
-    MEDIAPIPE_ASSERT_OK(runner.Run());
+    MP_ASSERT_OK(runner.Run());
    EXPECT_EQ(6, runner.Outputs().Index(0).packets.size());
  }
 }
@@ -0,0 +1,304 @@
+// Copyright 2019 The MediaPipe Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+// Declaration of PacketThinnerCalculator.
+
+#include <cmath>  // for ceil
+#include <memory>
+
+#include "mediapipe/calculators/core/packet_thinner_calculator.pb.h"
+#include "mediapipe/framework/calculator_context.h"
+#include "mediapipe/framework/calculator_framework.h"
+#include "mediapipe/framework/formats/video_stream_header.h"
+#include "mediapipe/framework/port/integral_types.h"
+#include "mediapipe/framework/port/logging.h"
+#include "mediapipe/framework/port/status.h"
+
+namespace mediapipe {
+
+namespace {
+const double kTimebaseUs = 1000000;  // Microseconds.
+const char* const kPeriodTag = "PERIOD";
+}  // namespace
+
+// This calculator is used to thin an input stream of Packets.
+// An example application would be to sample decoded frames of video
+// at a coarser temporal resolution. Unless otherwise stated, all
+// timestamps are in units of microseconds.
+//
+// Thinning can be accomplished in one of two ways:
+// 1) asynchronous thinning (known below as async):
+//    Algorithm does not rely on a master clock and is parameterized only
+//    by a single option -- the period.  Once a packet is emitted, the
+//    thinner will discard subsequent packets for the duration of the period
+//    [Analogous to a refractory period during which packet emission is
+//    suppressed.]
+//    Packets arriving before start_time are discarded, as are packets
+//    arriving at or after end_time.
+// 2) synchronous thinning (known below as sync):
+//    There are two variants of this algorithm, both parameterized by a
+//    start_time and a period.  As in (1), packets arriving before start_time
+//    or at/after end_time are discarded.  Otherwise, at most one packet is
+//    emitted during a period, centered at timestamps generated by the
+//    expression:
+//      start_time + i * period  [where i is a non-negative integer]
+//    During each period, the packet closest to the generated timestamp is
+//    emitted (latest in the case of ties).  In the first variant
+//    (sync_output_timestamps = true), the emitted packet is output at the
+//    generated timestamp.  In the second variant, the packet is output at
+//    its original timestamp.  Both variants emit exactly the same packets,
+//    but at different timestamps.
+//
+// Thinning period can be provided in the calculator options or via a
+// side packet with the tag "PERIOD".
+//
+// Example config:
+// node {
+//   calculator: "PacketThinnerCalculator"
+//   input_stream: "signal"
+//   output_stream: "output"
+//   options {
+//     [mediapipe.PacketThinnerCalculatorOptions.ext] {
+//       thinner_type: SYNC
+//       period: 10
+//       sync_output_timestamps: true
+//       update_frame_rate: false
+//     }
+//   }
+// }
+class PacketThinnerCalculator : public CalculatorBase {
+ public:
+  PacketThinnerCalculator() {}
+  ~PacketThinnerCalculator() override {}
+
+  static ::mediapipe::Status GetContract(CalculatorContract* cc) {
+    cc->Inputs().Index(0).SetAny();
+    cc->Outputs().Index(0).SetSameAs(&cc->Inputs().Index(0));
+    if (cc->InputSidePackets().HasTag(kPeriodTag)) {
+      cc->InputSidePackets().Tag(kPeriodTag).Set<int64>();
+    }
+    return ::mediapipe::OkStatus();
+  }
+
+  ::mediapipe::Status Open(CalculatorContext* cc) override;
+  ::mediapipe::Status Close(CalculatorContext* cc) override;
+  ::mediapipe::Status Process(CalculatorContext* cc) override {
+    if (cc->InputTimestamp() < start_time_) {
+      return ::mediapipe::OkStatus();  // Drop packets before start_time_.
+    } else if (cc->InputTimestamp() >= end_time_) {
+      if (!cc->Outputs().Index(0).IsClosed()) {
+        cc->Outputs()
+            .Index(0)
+            .Close();  // No more Packets will be output after end_time_.
+      }
+      return ::mediapipe::OkStatus();
+    } else {
+      return thinner_type_ == PacketThinnerCalculatorOptions::ASYNC
+                 ? AsyncThinnerProcess(cc)
+                 : SyncThinnerProcess(cc);
+    }
+  }
+
+ private:
+  // Implementation of ASYNC and SYNC versions of thinner algorithm.
+  ::mediapipe::Status AsyncThinnerProcess(CalculatorContext* cc);
+  ::mediapipe::Status SyncThinnerProcess(CalculatorContext* cc);
+
+  // Cached option.
+  PacketThinnerCalculatorOptions::ThinnerType thinner_type_;
+
+  // Given a Timestamp, finds the closest sync Timestamp
+  // based on start_time_ and period_.  This can be earlier or
+  // later than given Timestamp, but is guaranteed to be within
+  // half a period_.
+  Timestamp NearestSyncTimestamp(Timestamp now) const;
+
+  // Cached option used by both async and sync thinners.
+  TimestampDiff period_;  // Interval during which only one packet is emitted.
+  Timestamp start_time_;  // Cached option - default Timestamp::Min()
+  Timestamp end_time_;    // Cached option - default Timestamp::Max()
+
+  // Only used by async thinner:
+  Timestamp next_valid_timestamp_;  // Suppress packets until this timestamp.
+
+  // Only used by sync thinner:
+  Packet saved_packet_;          // Best packet not yet emitted.
+  bool sync_output_timestamps_;  // Cached option.
+};
+REGISTER_CALCULATOR(PacketThinnerCalculator);
+
+namespace {
+TimestampDiff abs(TimestampDiff t) { return t < 0 ? -t : t; }
+}  // namespace
+
+::mediapipe::Status PacketThinnerCalculator::Open(CalculatorContext* cc) {
+  auto& options = cc->Options<PacketThinnerCalculatorOptions>();
+
+  thinner_type_ = options.thinner_type();
+  // This check enables us to assume only two thinner types exist in Process()
+  CHECK(thinner_type_ == PacketThinnerCalculatorOptions::ASYNC ||
+        thinner_type_ == PacketThinnerCalculatorOptions::SYNC)
+      << "Unsupported thinner type.";
+
+  if (thinner_type_ == PacketThinnerCalculatorOptions::ASYNC) {
+    // ASYNC thinner outputs packets with the same timestamp as their input so
+    // its safe to SetOffset(0). SYNC thinner manipulates timestamps of its
+    // output so we don't do this for that case.
+    cc->SetOffset(0);
+  }
+
+  if (cc->InputSidePackets().HasTag(kPeriodTag)) {
+    period_ =
+        TimestampDiff(cc->InputSidePackets().Tag(kPeriodTag).Get<int64>());
+  } else {
+    period_ = TimestampDiff(options.period());
+  }
+  CHECK_LT(TimestampDiff(0), period_) << "Specified period must be positive.";
+
+  if (options.has_start_time()) {
+    start_time_ = Timestamp(options.start_time());
+  } else if (thinner_type_ == PacketThinnerCalculatorOptions::ASYNC) {
+    start_time_ = Timestamp::Min();
+  } else {
+    start_time_ = Timestamp(0);
+  }
+
+  end_time_ =
+      options.has_end_time() ? Timestamp(options.end_time()) : Timestamp::Max();
+  CHECK_LT(start_time_, end_time_)
+      << "Invalid PacketThinner: start_time must be earlier than end_time";
+
+  sync_output_timestamps_ = options.sync_output_timestamps();
+
+  next_valid_timestamp_ = start_time_;
+  // Drop packets until this time.
+  cc->Outputs().Index(0).SetNextTimestampBound(start_time_);
+
+  if (!cc->Inputs().Index(0).Header().IsEmpty()) {
+    if (options.update_frame_rate()) {
+      const VideoHeader& video_header =
+          cc->Inputs().Index(0).Header().Get<VideoHeader>();
+      double new_frame_rate;
+      if (thinner_type_ == PacketThinnerCalculatorOptions::ASYNC) {
+        new_frame_rate =
+            video_header.frame_rate /
+            ceil(video_header.frame_rate * options.period() / kTimebaseUs);
+      } else {
+        const double sampling_rate = kTimebaseUs / options.period();
+        new_frame_rate = video_header.frame_rate < sampling_rate
+                             ? video_header.frame_rate
+                             : sampling_rate;
+      }
+      std::unique_ptr<VideoHeader> header(new VideoHeader);
+      header->format = video_header.format;
+      header->width = video_header.width;
+      header->height = video_header.height;
+      header->frame_rate = new_frame_rate;
+      cc->Outputs().Index(0).SetHeader(Adopt(header.release()));
+    } else {
+      cc->Outputs().Index(0).SetHeader(cc->Inputs().Index(0).Header());
+    }
+  }
+
+  return ::mediapipe::OkStatus();
+}
+
+::mediapipe::Status PacketThinnerCalculator::Close(CalculatorContext* cc) {
+  // Emit any saved packets before quitting.
+  if (!saved_packet_.IsEmpty()) {
+    // Only sync thinner should have saved packets.
+    CHECK_EQ(PacketThinnerCalculatorOptions::SYNC, thinner_type_);
+    if (sync_output_timestamps_) {
+      cc->Outputs().Index(0).AddPacket(
+          saved_packet_.At(NearestSyncTimestamp(saved_packet_.Timestamp())));
+    } else {
+      cc->Outputs().Index(0).AddPacket(saved_packet_);
+    }
+  }
+  return ::mediapipe::OkStatus();
+}
+
+::mediapipe::Status PacketThinnerCalculator::AsyncThinnerProcess(
+    CalculatorContext* cc) {
+  if (cc->InputTimestamp() >= next_valid_timestamp_) {
+    cc->Outputs().Index(0).AddPacket(
+        cc->Inputs().Index(0).Value());  // Emit current packet.
+    next_valid_timestamp_ = cc->InputTimestamp() + period_;
+    // Guaranteed not to emit packets seen during refractory period.
+    cc->Outputs().Index(0).SetNextTimestampBound(next_valid_timestamp_);
+  }
+  return ::mediapipe::OkStatus();
+}
+
+::mediapipe::Status PacketThinnerCalculator::SyncThinnerProcess(
+    CalculatorContext* cc) {
+  if (saved_packet_.IsEmpty()) {
+    // If no packet has been saved, store the current packet.
+    saved_packet_ = cc->Inputs().Index(0).Value();
+    cc->Outputs().Index(0).SetNextTimestampBound(
+        sync_output_timestamps_ ? NearestSyncTimestamp(cc->InputTimestamp())
+                                : cc->InputTimestamp());
+  } else {
+    // Saved packet exists -- update or emit.
+    const Timestamp saved = saved_packet_.Timestamp();
+    const Timestamp saved_sync = NearestSyncTimestamp(saved);
+    const Timestamp now = cc->InputTimestamp();
+    const Timestamp now_sync = NearestSyncTimestamp(now);
+    CHECK_LE(saved_sync, now_sync);
+    if (saved_sync == now_sync) {
+      // Saved Packet is in same interval as current packet.
+      // Replace saved packet with current if it is at least as
+      // central as the saved packet wrt temporal interval.
+      // [We break ties in favor of fresher packets]
+      if (abs(now - now_sync) <= abs(saved - saved_sync)) {
+        saved_packet_ = cc->Inputs().Index(0).Value();
+      }
+    } else {
+      // Saved packet is the best packet from earlier interval: emit!
+      if (sync_output_timestamps_) {
+        cc->Outputs().Index(0).AddPacket(saved_packet_.At(saved_sync));
+        cc->Outputs().Index(0).SetNextTimestampBound(now_sync);
+      } else {
+        cc->Outputs().Index(0).AddPacket(saved_packet_);
+        cc->Outputs().Index(0).SetNextTimestampBound(now);
+      }
+      // Current packet is the first one we've seen from new interval -- save!
+      saved_packet_ = cc->Inputs().Index(0).Value();
+    }
+  }
+  return ::mediapipe::OkStatus();
+}
+
+Timestamp PacketThinnerCalculator::NearestSyncTimestamp(Timestamp now) const {
+  CHECK_NE(start_time_, Timestamp::Unset())
+      << "Method only valid for sync thinner calculator.";
+
+  // Computation is done using int64 arithmetic.  No easy way to avoid
+  // since Timestamps don't support div and multiply.
+  const int64 now64 = now.Value();
+  const int64 start64 = start_time_.Value();
+  const int64 period64 = period_.Value();
+  CHECK_LE(0, period64);
+
+  // Round now64 to its closest interval (units of period64).
+  int64 sync64 =
+      (now64 - start64 + period64 / 2) / period64 * period64 + start64;
+  CHECK_LE(abs(now64 - sync64), period64 / 2)
+      << "start64: " << start64 << "; now64: " << now64
+      << "; sync64: " << sync64;
+
+  return Timestamp(sync64);
+}
+
+}  // namespace mediapipe
@@ -0,0 +1,66 @@
+// Copyright 2018 The MediaPipe Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+syntax = "proto2";
+
+package mediapipe;
+
+import "mediapipe/framework/calculator.proto";
+
+message PacketThinnerCalculatorOptions {
+  extend CalculatorOptions {
+    optional PacketThinnerCalculatorOptions ext = 288533508;
+  }
+
+  enum ThinnerType {
+    ASYNC = 1;  // Asynchronous thinner, described below [default].
+    SYNC = 2;   // Synchronous thinner, also described below.
+  }
+  optional ThinnerType thinner_type = 1 [default = ASYNC];
+
+  // The period (in microsecond) specifies the temporal interval during which
+  // only a single packet is emitted in the output stream.  Has subtly different
+  // semantics depending on the thinner type, as follows.
+  //
+  // Async thinner: this option is a refractory period -- once a packet is
+  // emitted, we guarantee that no packets will be emitted for period ticks.
+  //
+  // Sync thinner: the period specifies a temporal interval during which
+  // only one packet is emitted.  The emitted packet is guaranteed to be
+  // the one closest to the center of the temporal interval (no guarantee on
+  // how ties are broken).  More specifically,
+  //   intervals are centered at start_time + i * period
+  //   (for non-negative integers i).
+  // Thus, each interval extends period/2 ticks before and after its center.
+  // Additionally, in the sync thinner any packets earlier than start_time
+  // are discarded and the thinner calls Close() once timestamp equals or
+  // exceeds end_time.
+  optional int64 period = 2 [default = 1];
+
+  // Packets before start_time and at/after end_time are discarded.
+  // Additionally, for a sync thinner, start time specifies the center of
+  // time invervals as described above and therefore should be set explicitly.
+  optional int64 start_time = 3;  // If not specified, set to 0 for SYNC type,
+                                  // and set to Timestamp::Min() for ASYNC type.
+  optional int64 end_time = 4;    // Set to Timestamp::Max() if not specified.
+
+  // Whether the timestamps of packets emitted by sync thinner should
+  // correspond to the center of their corresponding temporal interval.
+  // If false, packets emitted using original timestamp (as in async thinner).
+  optional bool sync_output_timestamps = 5 [default = true];
+
+  // If true, update the frame rate in the header, if it's available, to an
+  // estimated frame rate due to the sampling.
+  optional bool update_frame_rate = 6 [default = false];
+}
@@ -0,0 +1,357 @@
+// Copyright 2019 The MediaPipe Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include <memory>
+#include <string>
+#include <vector>
+
+#include "absl/strings/str_cat.h"
+#include "mediapipe/calculators/core/packet_thinner_calculator.pb.h"
+#include "mediapipe/framework/calculator_framework.h"
+#include "mediapipe/framework/calculator_runner.h"
+#include "mediapipe/framework/formats/video_stream_header.h"
+#include "mediapipe/framework/port/gmock.h"
+#include "mediapipe/framework/port/gtest.h"
+#include "mediapipe/framework/port/integral_types.h"
+#include "mediapipe/framework/port/status_matchers.h"
+
+namespace mediapipe {
+namespace {
+
+// A simple version of CalculatorRunner with built-in convenience methods for
+// setting inputs from a vector and checking outputs against a vector of
+// expected outputs.
+class SimpleRunner : public CalculatorRunner {
+ public:
+  explicit SimpleRunner(const CalculatorOptions& options)
+      : CalculatorRunner("PacketThinnerCalculator", options) {
+    SetNumInputs(1);
+    SetNumOutputs(1);
+    SetNumInputSidePackets(0);
+  }
+
+  explicit SimpleRunner(const CalculatorGraphConfig::Node& node)
+      : CalculatorRunner(node) {}
+
+  void SetInput(const std::vector<int>& timestamp_list) {
+    MutableInputs()->Index(0).packets.clear();
+    for (const int ts : timestamp_list) {
+      MutableInputs()->Index(0).packets.push_back(
+          MakePacket<std::string>(absl::StrCat("Frame #", ts))
+              .At(Timestamp(ts)));
+    }
+  }
+
+  void SetFrameRate(const double frame_rate) {
+    auto video_header = absl::make_unique<VideoHeader>();
+    video_header->frame_rate = frame_rate;
+    MutableInputs()->Index(0).header = Adopt(video_header.release());
+  }
+
+  std::vector<int64> GetOutputTimestamps() const {
+    std::vector<int64> timestamps;
+    for (const Packet& packet : Outputs().Index(0).packets) {
+      timestamps.emplace_back(packet.Timestamp().Value());
+    }
+    return timestamps;
+  }
+
+  double GetFrameRate() const {
+    CHECK(!Outputs().Index(0).header.IsEmpty());
+    return Outputs().Index(0).header.Get<VideoHeader>().frame_rate;
+  }
+};
+
+// Check that thinner respects start_time and end_time options.
+// We only test with one thinner because the logic for start & end time
+// handling is shared across both types of thinner in Process().
+TEST(PacketThinnerCalculatorTest, StartAndEndTimeTest) {
+  CalculatorOptions options;
+  auto* extension =
+      options.MutableExtension(PacketThinnerCalculatorOptions::ext);
+  extension->set_thinner_type(PacketThinnerCalculatorOptions::ASYNC);
+  extension->set_period(5);
+  extension->set_start_time(4);
+  extension->set_end_time(12);
+  SimpleRunner runner(options);
+  runner.SetInput({2, 3, 5, 7, 11, 13, 17, 19, 23, 29});
+  MP_ASSERT_OK(runner.Run());
+
+  const std::vector<int64> expected_timestamps = {5, 11};
+  EXPECT_EQ(expected_timestamps, runner.GetOutputTimestamps());
+}
+
+TEST(PacketThinnerCalculatorTest, AsyncUniformStreamThinningTest) {
+  CalculatorOptions options;
+  auto* extension =
+      options.MutableExtension(PacketThinnerCalculatorOptions::ext);
+  extension->set_thinner_type(PacketThinnerCalculatorOptions::ASYNC);
+  extension->set_period(5);
+  SimpleRunner runner(options);
+  runner.SetInput({2, 4, 6, 8, 10, 12, 14});
+  MP_ASSERT_OK(runner.Run());
+
+  const std::vector<int64> expected_timestamps = {2, 8, 14};
+  EXPECT_EQ(expected_timestamps, runner.GetOutputTimestamps());
+}
+
+TEST(PacketThinnerCalculatorTest, ASyncUniformStreamThinningTestBySidePacket) {
+  // Note: sync runner but outputting *original* timestamps.
+  CalculatorGraphConfig::Node node;
+  node.set_calculator("PacketThinnerCalculator");
+  node.add_input_side_packet("PERIOD:period");
+  node.add_input_stream("input_stream");
+  node.add_output_stream("output_stream");
+  auto* extension = node.mutable_options()->MutableExtension(
+      PacketThinnerCalculatorOptions::ext);
+  extension->set_thinner_type(PacketThinnerCalculatorOptions::ASYNC);
+  extension->set_start_time(0);
+  extension->set_sync_output_timestamps(false);
+
+  SimpleRunner runner(node);
+  runner.SetInput({2, 4, 6, 8, 10, 12, 14});
+  runner.MutableSidePackets()->Tag("PERIOD") = MakePacket<int64>(5);
+  MP_ASSERT_OK(runner.Run());
+
+  const std::vector<int64> expected_timestamps = {2, 8, 14};
+  EXPECT_EQ(expected_timestamps, runner.GetOutputTimestamps());
+}
+
+TEST(PacketThinnerCalculatorTest, SyncUniformStreamThinningTest1) {
+  // Note: sync runner but outputting *original* timestamps.
+  CalculatorOptions options;
+  auto* extension =
+      options.MutableExtension(PacketThinnerCalculatorOptions::ext);
+  extension->set_thinner_type(PacketThinnerCalculatorOptions::SYNC);
+  extension->set_start_time(0);
+  extension->set_period(5);
+  extension->set_sync_output_timestamps(false);
+  SimpleRunner runner(options);
+  runner.SetInput({2, 4, 6, 8, 10, 12, 14});
+  MP_ASSERT_OK(runner.Run());
+
+  const std::vector<int64> expected_timestamps = {2, 6, 10, 14};
+  EXPECT_EQ(expected_timestamps, runner.GetOutputTimestamps());
+}
+
+TEST(PacketThinnerCalculatorTest, SyncUniformStreamThinningTestBySidePacket1) {
+  // Note: sync runner but outputting *original* timestamps.
+  CalculatorGraphConfig::Node node;
+  node.set_calculator("PacketThinnerCalculator");
+  node.add_input_side_packet("PERIOD:period");
+  node.add_input_stream("input_stream");
+  node.add_output_stream("output_stream");
+  auto* extension = node.mutable_options()->MutableExtension(
+      PacketThinnerCalculatorOptions::ext);
+  extension->set_thinner_type(PacketThinnerCalculatorOptions::SYNC);
+  extension->set_start_time(0);
+  extension->set_sync_output_timestamps(false);
+
+  SimpleRunner runner(node);
+  runner.SetInput({2, 4, 6, 8, 10, 12, 14});
+  runner.MutableSidePackets()->Tag("PERIOD") = MakePacket<int64>(5);
+  MP_ASSERT_OK(runner.Run());
+
+  const std::vector<int64> expected_timestamps = {2, 6, 10, 14};
+  EXPECT_EQ(expected_timestamps, runner.GetOutputTimestamps());
+}
+
+TEST(PacketThinnerCalculatorTest, SyncUniformStreamThinningTest2) {
+  // Same test but now with synced timestamps.
+  CalculatorOptions options;
+  auto* extension =
+      options.MutableExtension(PacketThinnerCalculatorOptions::ext);
+  extension->set_thinner_type(PacketThinnerCalculatorOptions::SYNC);
+  extension->set_start_time(0);
+  extension->set_period(5);
+  extension->set_sync_output_timestamps(true);
+  SimpleRunner runner(options);
+  runner.SetInput({2, 4, 6, 8, 10, 12, 14});
+  MP_ASSERT_OK(runner.Run());
+
+  const std::vector<int64> expected_timestamps = {0, 5, 10, 15};
+  EXPECT_EQ(expected_timestamps, runner.GetOutputTimestamps());
+}
+
+// Test: Given a stream with timestamps corresponding to first ten prime numbers
+// and period of 5, confirm whether timestamps of thinner stream matches
+// expectations.
+TEST(PacketThinnerCalculatorTest, PrimeStreamThinningTest1) {
+  // ASYNC thinner.
+  CalculatorOptions options;
+  auto* extension =
+      options.MutableExtension(PacketThinnerCalculatorOptions::ext);
+  extension->set_thinner_type(PacketThinnerCalculatorOptions::ASYNC);
+  extension->set_period(5);
+  SimpleRunner runner(options);
+  runner.SetInput({2, 3, 5, 7, 11, 13, 17, 19, 23, 29});
+  MP_ASSERT_OK(runner.Run());
+
+  const std::vector<int64> expected_timestamps = {2, 7, 13, 19, 29};
+  EXPECT_EQ(expected_timestamps, runner.GetOutputTimestamps());
+}
+
+TEST(PacketThinnerCalculatorTest, PrimeStreamThinningTest2) {
+  // SYNC with original timestamps.
+  CalculatorOptions options;
+  auto* extension =
+      options.MutableExtension(PacketThinnerCalculatorOptions::ext);
+  extension->set_thinner_type(PacketThinnerCalculatorOptions::SYNC);
+  extension->set_start_time(0);
+  extension->set_period(5);
+  extension->set_sync_output_timestamps(false);
+  SimpleRunner runner(options);
+  runner.SetInput({2, 3, 5, 7, 11, 13, 17, 19, 23, 29});
+  MP_ASSERT_OK(runner.Run());
+
+  const std::vector<int64> expected_timestamps = {2, 5, 11, 17, 19, 23, 29};
+  EXPECT_EQ(expected_timestamps, runner.GetOutputTimestamps());
+}
+
+// Confirm that Calculator correctly handles boundary cases.
+TEST(PacketThinnerCalculatorTest, BoundaryTimestampTest1) {
+  // Odd period, negative start_time
+  CalculatorOptions options;
+  auto* extension =
+      options.MutableExtension(PacketThinnerCalculatorOptions::ext);
+  extension->set_thinner_type(PacketThinnerCalculatorOptions::SYNC);
+  extension->set_start_time(-10);
+  extension->set_period(5);
+  extension->set_sync_output_timestamps(true);
+  SimpleRunner runner(options);
+  // Two timestamps falling on either side of a period boundary.
+  runner.SetInput({2, 3});
+  MP_ASSERT_OK(runner.Run());
+
+  const std::vector<int64> expected_timestamps = {0, 5};
+  EXPECT_EQ(expected_timestamps, runner.GetOutputTimestamps());
+}
+
+TEST(PacketThinnerCalculatorTest, BoundaryTimestampTest2) {
+  // Even period, negative start_time, negative packet timestamps.
+  CalculatorOptions options;
+  auto* extension =
+      options.MutableExtension(PacketThinnerCalculatorOptions::ext);
+  extension->set_thinner_type(PacketThinnerCalculatorOptions::SYNC);
+  extension->set_start_time(-144);
+  extension->set_period(6);
+  extension->set_sync_output_timestamps(true);
+  SimpleRunner runner(options);
+  // Two timestamps falling on either side of a period boundary.
+  runner.SetInput({-4, -3, 8, 9});
+  MP_ASSERT_OK(runner.Run());
+
+  const std::vector<int64> expected_timestamps = {-6, 0, 6, 12};
+  EXPECT_EQ(expected_timestamps, runner.GetOutputTimestamps());
+}
+
+TEST(PacketThinnerCalculatorTest, FrameRateTest1) {
+  CalculatorOptions options;
+  auto* extension =
+      options.MutableExtension(PacketThinnerCalculatorOptions::ext);
+  extension->set_thinner_type(PacketThinnerCalculatorOptions::ASYNC);
+  extension->set_period(5);
+  extension->set_update_frame_rate(true);
+  SimpleRunner runner(options);
+  runner.SetInput({2, 4, 6, 8, 10, 12, 14});
+  runner.SetFrameRate(1000000.0 / 2);
+  MP_ASSERT_OK(runner.Run());
+
+  const std::vector<int64> expected_timestamps = {2, 8, 14};
+  EXPECT_EQ(expected_timestamps, runner.GetOutputTimestamps());
+  // The true sampling period is 6.
+  EXPECT_DOUBLE_EQ(1000000.0 / 6, runner.GetFrameRate());
+}
+
+TEST(PacketThinnerCalculatorTest, FrameRateTest2) {
+  CalculatorOptions options;
+  auto* extension =
+      options.MutableExtension(PacketThinnerCalculatorOptions::ext);
+  extension->set_thinner_type(PacketThinnerCalculatorOptions::ASYNC);
+  extension->set_period(5);
+  extension->set_update_frame_rate(true);
+  SimpleRunner runner(options);
+  runner.SetInput({8, 16, 24, 32, 40, 48, 56});
+  runner.SetFrameRate(1000000.0 / 8);
+  MP_ASSERT_OK(runner.Run());
+  const std::vector<int64> expected_timestamps = {8, 16, 24, 32, 40, 48, 56};
+  EXPECT_EQ(expected_timestamps, runner.GetOutputTimestamps());
+  // The true sampling period is still 8.
+  EXPECT_DOUBLE_EQ(1000000.0 / 8, runner.GetFrameRate());
+}
+
+TEST(PacketThinnerCalculatorTest, FrameRateTest3) {
+  // Note: sync runner but outputting *original* timestamps.
+  CalculatorOptions options;
+  auto* extension =
+      options.MutableExtension(PacketThinnerCalculatorOptions::ext);
+  extension->set_thinner_type(PacketThinnerCalculatorOptions::SYNC);
+  extension->set_start_time(0);
+  extension->set_period(5);
+  extension->set_sync_output_timestamps(false);
+  extension->set_update_frame_rate(true);
+  SimpleRunner runner(options);
+  runner.SetInput({2, 4, 6, 8, 10, 12, 14});
+  runner.SetFrameRate(1000000.0 / 2);
+  MP_ASSERT_OK(runner.Run());
+
+  const std::vector<int64> expected_timestamps = {2, 6, 10, 14};
+  EXPECT_EQ(expected_timestamps, runner.GetOutputTimestamps());
+  // The true (long-run) sampling period is 5.
+  EXPECT_DOUBLE_EQ(1000000.0 / 5, runner.GetFrameRate());
+}
+
+TEST(PacketThinnerCalculatorTest, FrameRateTest4) {
+  // Same test but now with synced timestamps.
+  CalculatorOptions options;
+  auto* extension =
+      options.MutableExtension(PacketThinnerCalculatorOptions::ext);
+  extension->set_thinner_type(PacketThinnerCalculatorOptions::SYNC);
+  extension->set_start_time(0);
+  extension->set_period(5);
+  extension->set_sync_output_timestamps(true);
+  extension->set_update_frame_rate(true);
+  SimpleRunner runner(options);
+  runner.SetInput({2, 4, 6, 8, 10, 12, 14});
+  runner.SetFrameRate(1000000.0 / 2);
+  MP_ASSERT_OK(runner.Run());
+
+  const std::vector<int64> expected_timestamps = {0, 5, 10, 15};
+  EXPECT_EQ(expected_timestamps, runner.GetOutputTimestamps());
+  // The true (long-run) sampling period is 5.
+  EXPECT_DOUBLE_EQ(1000000.0 / 5, runner.GetFrameRate());
+}
+
+TEST(PacketThinnerCalculatorTest, FrameRateTest5) {
+  CalculatorOptions options;
+  auto* extension =
+      options.MutableExtension(PacketThinnerCalculatorOptions::ext);
+  extension->set_thinner_type(PacketThinnerCalculatorOptions::SYNC);
+  extension->set_start_time(0);
+  extension->set_period(5);
+  extension->set_sync_output_timestamps(true);
+  extension->set_update_frame_rate(true);
+  SimpleRunner runner(options);
+  runner.SetInput({8, 16, 24, 32, 40, 48, 56});
+  runner.SetFrameRate(1000000.0 / 8);
+  MP_ASSERT_OK(runner.Run());
+
+  const std::vector<int64> expected_timestamps = {10, 15, 25, 30, 40, 50, 55};
+  EXPECT_EQ(expected_timestamps, runner.GetOutputTimestamps());
+  // The true (long-run) sampling period is 8.
+  EXPECT_DOUBLE_EQ(1000000.0 / 8, runner.GetFrameRate());
+}
+
+}  // namespace
+}  // namespace mediapipe
@@ -17,6 +17,7 @@
 #include "mediapipe/framework/calculator_framework.h"
 #include "mediapipe/framework/port/ret_check.h"
 #include "mediapipe/framework/port/status.h"
+#include "mediapipe/framework/timestamp.h"

 namespace mediapipe {

@@ -24,13 +25,17 @@ namespace mediapipe {
 // together with some previous output.
 //
 // For the first packet that arrives on the MAIN input, the timestamp bound is
-// advanced on the output. Downstream calculators will see this as an empty
+// advanced on the PREV_LOOP. Downstream calculators will see this as an empty
 // packet. This way they are not kept waiting for the previous output, which
 // for the first iteration does not exist.
 //
-// Thereafter, each packet received on MAIN is matched with a packet received
-// on LOOP; the LOOP packet's timestamp is changed to that of the MAIN packet,
-// and it is output on PREV_LOOP.
+// Thereafter,
+// - Each non-empty MAIN packet results in:
+//   a) a PREV_LOOP packet with contents of the LOOP packet received at the
+//      timestamp of the previous non-empty MAIN packet
+//   b) or in a PREV_LOOP timestamp bound update if the LOOP packet was empty.
+// - Each empty MAIN packet indicating timestamp bound update results in a
+//   PREV_LOOP timestamp bound update.
 //
 // Example config:
 // node {
@@ -55,63 +60,115 @@ class PreviousLoopbackCalculator : public CalculatorBase {
    // TODO: an optional PREV_TIMESTAMP output could be added to
    // carry the original timestamp of the packet on PREV_LOOP.
    cc->SetInputStreamHandler("ImmediateInputStreamHandler");
+    // Process() function is invoked in response to MAIN/LOOP stream timestamp
+    // bound updates.
+    cc->SetProcessTimestampBounds(true);
    return ::mediapipe::OkStatus();
  }

  ::mediapipe::Status Open(CalculatorContext* cc) final {
    main_id_ = cc->Inputs().GetId("MAIN", 0);
    loop_id_ = cc->Inputs().GetId("LOOP", 0);
-    loop_out_id_ = cc->Outputs().GetId("PREV_LOOP", 0);
+    prev_loop_id_ = cc->Outputs().GetId("PREV_LOOP", 0);
    cc->Outputs()
-        .Get(loop_out_id_)
+        .Get(prev_loop_id_)
        .SetHeader(cc->Inputs().Get(loop_id_).Header());
-
-    // Use an empty packet for the first round, since there is no previous
-    // output.
-    loopback_packets_.push_back({});
-
    return ::mediapipe::OkStatus();
  }

  ::mediapipe::Status Process(CalculatorContext* cc) final {
-    Packet& main_packet = cc->Inputs().Get(main_id_).Value();
-    if (!main_packet.IsEmpty()) {
-      main_ts_.push_back(main_packet.Timestamp());
-    }
-    Packet& loopback_packet = cc->Inputs().Get(loop_id_).Value();
-    if (!loopback_packet.IsEmpty()) {
-      loopback_packets_.push_back(loopback_packet);
-      while (!main_ts_.empty() &&
-             main_ts_.front() <= loopback_packets_.front().Timestamp()) {
-        main_ts_.pop_front();
-      }
-    }
+    // Non-empty packets and empty packets indicating timestamp bound updates
+    // are guaranteed to have timestamps greater than timestamps of previous
+    // packets within the same stream. Calculator tracks and operates on such
+    // packets.

-    while (!main_ts_.empty() && !loopback_packets_.empty()) {
-      Timestamp main_timestamp = main_ts_.front();
-      main_ts_.pop_front();
-      Packet previous_loopback = loopback_packets_.front().At(main_timestamp);
-      loopback_packets_.pop_front();
-
-      if (previous_loopback.IsEmpty()) {
-        // TODO: SetCompleteTimestampBound would be more useful.
-        cc->Outputs()
-            .Get(loop_out_id_)
-            .SetNextTimestampBound(main_timestamp + 1);
+    const Packet& main_packet = cc->Inputs().Get(main_id_).Value();
+    if (prev_main_ts_ < main_packet.Timestamp()) {
+      Timestamp loop_timestamp;
+      if (!main_packet.IsEmpty()) {
+        loop_timestamp = prev_non_empty_main_ts_;
+        prev_non_empty_main_ts_ = main_packet.Timestamp();
      } else {
-        cc->Outputs().Get(loop_out_id_).AddPacket(std::move(previous_loopback));
+        // Calculator advances PREV_LOOP timestamp bound in response to empty
+        // MAIN packet, hence not caring about corresponding loop packet.
+        loop_timestamp = Timestamp::Unset();
      }
+      main_packet_specs_.push_back({.timestamp = main_packet.Timestamp(),
+                                    .loop_timestamp = loop_timestamp});
+      prev_main_ts_ = main_packet.Timestamp();
+    }
+
+    const Packet& loop_packet = cc->Inputs().Get(loop_id_).Value();
+    if (prev_loop_ts_ < loop_packet.Timestamp()) {
+      loop_packets_.push_back(loop_packet);
+      prev_loop_ts_ = loop_packet.Timestamp();
+    }
+
+    auto& prev_loop = cc->Outputs().Get(prev_loop_id_);
+    while (!main_packet_specs_.empty() && !loop_packets_.empty()) {
+      // The earliest MAIN packet.
+      const MainPacketSpec& main_spec = main_packet_specs_.front();
+      // The earliest LOOP packet.
+      const Packet& loop_candidate = loop_packets_.front();
+      // Match LOOP and MAIN packets.
+      if (main_spec.loop_timestamp < loop_candidate.Timestamp()) {
+        // No LOOP packet can match the MAIN packet under review.
+        prev_loop.SetNextTimestampBound(main_spec.timestamp + 1);
+        main_packet_specs_.pop_front();
+      } else if (main_spec.loop_timestamp > loop_candidate.Timestamp()) {
+        // No MAIN packet can match the LOOP packet under review.
+        loop_packets_.pop_front();
+      } else {
+        // Exact match found.
+        if (loop_candidate.IsEmpty()) {
+          // However, LOOP packet is empty.
+          prev_loop.SetNextTimestampBound(main_spec.timestamp + 1);
+        } else {
+          prev_loop.AddPacket(loop_candidate.At(main_spec.timestamp));
+        }
+        loop_packets_.pop_front();
+        main_packet_specs_.pop_front();
+      }
+    }
+
+    if (main_packet_specs_.empty() && cc->Inputs().Get(main_id_).IsDone()) {
+      prev_loop.Close();
    }
    return ::mediapipe::OkStatus();
  }

 private:
+  struct MainPacketSpec {
+    Timestamp timestamp;
+    // Expected timestamp of the packet from LOOP stream that corresponds to the
+    // packet from MAIN stream descirbed by this spec.
+    Timestamp loop_timestamp;
+  };
+
  CollectionItemId main_id_;
  CollectionItemId loop_id_;
-  CollectionItemId loop_out_id_;
+  CollectionItemId prev_loop_id_;

-  std::deque<Timestamp> main_ts_;
-  std::deque<Packet> loopback_packets_;
+  // Contains specs for MAIN packets which only can be:
+  // - non-empty packets
+  // - empty packets indicating timestamp bound updates
+  //
+  // Sorted according to packet timestamps.
+  std::deque<MainPacketSpec> main_packet_specs_;
+  Timestamp prev_main_ts_ = Timestamp::Unstarted();
+  Timestamp prev_non_empty_main_ts_ = Timestamp::Unstarted();
+
+  // Contains LOOP packets which only can be:
+  // - the very first empty packet
+  // - non empty packets
+  // - empty packets indicating timestamp bound updates
+  //
+  // Sorted according to packet timestamps.
+  std::deque<Packet> loop_packets_;
+  // Using "Timestamp::Unset" instead of "Timestamp::Unstarted" in order to
+  // allow addition of the very first empty packet (which doesn't indicate
+  // timestamp bound change necessarily).
+  Timestamp prev_loop_ts_ = Timestamp::Unset();
 };
 REGISTER_CALCULATOR(PreviousLoopbackCalculator);

@@ -13,6 +13,7 @@
 // limitations under the License.

 #include <algorithm>
+#include <functional>
 #include <memory>
 #include <string>
 #include <vector>
@@ -25,12 +26,17 @@
 #include "mediapipe/framework/port/gtest.h"
 #include "mediapipe/framework/port/integral_types.h"
 #include "mediapipe/framework/port/parse_text_proto.h"
+#include "mediapipe/framework/port/status.h"
 #include "mediapipe/framework/port/status_matchers.h"
 #include "mediapipe/framework/timestamp.h"
 #include "mediapipe/framework/tool/sink.h"

 namespace mediapipe {

+using ::testing::ElementsAre;
+using ::testing::Eq;
+using ::testing::Pair;
+using ::testing::Value;
 namespace {

 // Returns the timestamp values for a vector of Packets.
@@ -43,6 +49,23 @@ std::vector<int64> TimestampValues(const std::vector<Packet>& packets) {
  return result;
 }

+MATCHER(EmptyPacket, negation ? "isn't empty" : "is empty") {
+  if (arg.IsEmpty()) {
+    return true;
+  }
+  return false;
+}
+
+MATCHER_P(IntPacket, value, "") {
+  return Value(arg.template Get<int>(), Eq(value));
+}
+
+MATCHER_P2(PairPacket, timestamp, pair, "") {
+  Timestamp actual_timestamp = arg.Timestamp();
+  const auto& actual_pair = arg.template Get<std::pair<Packet, Packet>>();
+  return Value(actual_timestamp, Eq(timestamp)) && Value(actual_pair, pair);
+}
+
 TEST(PreviousLoopbackCalculator, CorrectTimestamps) {
  std::vector<Packet> in_prev;
  CalculatorGraphConfig graph_config_ =
@@ -74,37 +97,672 @@ TEST(PreviousLoopbackCalculator, CorrectTimestamps) {
  tool::AddVectorSink("pair", &graph_config_, &in_prev);

  CalculatorGraph graph_;
-  MEDIAPIPE_ASSERT_OK(graph_.Initialize(graph_config_, {}));
-  MEDIAPIPE_ASSERT_OK(graph_.StartRun({}));
+  MP_ASSERT_OK(graph_.Initialize(graph_config_, {}));
+  MP_ASSERT_OK(graph_.StartRun({}));

  auto send_packet = [&graph_](const std::string& input_name, int n) {
-    MEDIAPIPE_EXPECT_OK(graph_.AddPacketToInputStream(
+    MP_EXPECT_OK(graph_.AddPacketToInputStream(
        input_name, MakePacket<int>(n).At(Timestamp(n))));
  };
-  auto pair_values = [](const Packet& packet) {
-    auto pair = packet.Get<std::pair<Packet, Packet>>();
-    int first = pair.first.IsEmpty() ? -1 : pair.first.Get<int>();
-    int second = pair.second.IsEmpty() ? -1 : pair.second.Get<int>();
-    return std::make_pair(first, second);
-  };

  send_packet("in", 1);
-  MEDIAPIPE_EXPECT_OK(graph_.WaitUntilIdle());
-  EXPECT_EQ(TimestampValues(in_prev), (std::vector<int64>{1}));
-  EXPECT_EQ(pair_values(in_prev.back()), std::make_pair(1, -1));
+  MP_EXPECT_OK(graph_.WaitUntilIdle());
+  EXPECT_THAT(TimestampValues(in_prev), ElementsAre(1));
+  EXPECT_THAT(in_prev.back(),
+              PairPacket(Timestamp(1), Pair(IntPacket(1), EmptyPacket())));
+
+  send_packet("in", 2);
+  MP_EXPECT_OK(graph_.WaitUntilIdle());
+  EXPECT_THAT(TimestampValues(in_prev), ElementsAre(1, 2));
+  EXPECT_THAT(in_prev.back(),
+              PairPacket(Timestamp(2), Pair(IntPacket(2), IntPacket(1))));

  send_packet("in", 5);
-  MEDIAPIPE_EXPECT_OK(graph_.WaitUntilIdle());
-  EXPECT_EQ(TimestampValues(in_prev), (std::vector<int64>{1, 5}));
-  EXPECT_EQ(pair_values(in_prev.back()), std::make_pair(5, 1));
+  MP_EXPECT_OK(graph_.WaitUntilIdle());
+  EXPECT_THAT(TimestampValues(in_prev), ElementsAre(1, 2, 5));
+  EXPECT_THAT(in_prev.back(),
+              PairPacket(Timestamp(5), Pair(IntPacket(5), IntPacket(2))));

  send_packet("in", 15);
-  MEDIAPIPE_EXPECT_OK(graph_.WaitUntilIdle());
-  EXPECT_EQ(TimestampValues(in_prev), (std::vector<int64>{1, 5, 15}));
-  EXPECT_EQ(pair_values(in_prev.back()), std::make_pair(15, 5));
+  MP_EXPECT_OK(graph_.WaitUntilIdle());
+  EXPECT_THAT(TimestampValues(in_prev), ElementsAre(1, 2, 5, 15));
+  EXPECT_THAT(in_prev.back(),
+              PairPacket(Timestamp(15), Pair(IntPacket(15), IntPacket(5))));

-  MEDIAPIPE_EXPECT_OK(graph_.CloseAllInputStreams());
-  MEDIAPIPE_EXPECT_OK(graph_.WaitUntilDone());
+  MP_EXPECT_OK(graph_.CloseAllInputStreams());
+  MP_EXPECT_OK(graph_.WaitUntilDone());
+}
+
+// A Calculator that outputs a summary packet in CalculatorBase::Close().
+class PacketOnCloseCalculator : public CalculatorBase {
+ public:
+  static ::mediapipe::Status GetContract(CalculatorContract* cc) {
+    cc->Inputs().Index(0).Set<int>();
+    cc->Outputs().Index(0).Set<int>();
+    return ::mediapipe::OkStatus();
+  }
+
+  ::mediapipe::Status Open(CalculatorContext* cc) final {
+    cc->SetOffset(TimestampDiff(0));
+    return ::mediapipe::OkStatus();
+  }
+
+  ::mediapipe::Status Process(CalculatorContext* cc) final {
+    sum_ += cc->Inputs().Index(0).Value().Get<int>();
+    cc->Outputs().Index(0).AddPacket(cc->Inputs().Index(0).Value());
+    return ::mediapipe::OkStatus();
+  }
+
+  ::mediapipe::Status Close(CalculatorContext* cc) final {
+    cc->Outputs().Index(0).AddPacket(
+        MakePacket<int>(sum_).At(Timestamp::Max()));
+    return ::mediapipe::OkStatus();
+  }
+
+ private:
+  int sum_ = 0;
+};
+REGISTER_CALCULATOR(PacketOnCloseCalculator);
+
+// Demonstrates that all ouput and input streams in PreviousLoopbackCalculator
+// will close as expected when all graph input streams are closed.
+TEST(PreviousLoopbackCalculator, ClosesCorrectly) {
+  std::vector<Packet> outputs;
+  CalculatorGraphConfig graph_config_ =
+      ParseTextProtoOrDie<CalculatorGraphConfig>(R"(
+        input_stream: 'in'
+        node {
+          calculator: 'PreviousLoopbackCalculator'
+          input_stream: 'MAIN:in'
+          input_stream: 'LOOP:out'
+          input_stream_info: { tag_index: 'LOOP' back_edge: true }
+          output_stream: 'PREV_LOOP:previous'
+        }
+        # This calculator synchronizes its inputs as normal, so it is used
+        # to check that both "in" and "previous" are ready.
+        node {
+          calculator: 'PassThroughCalculator'
+          input_stream: 'in'
+          input_stream: 'previous'
+          output_stream: 'out'
+          output_stream: 'previous2'
+        }
+        node {
+          calculator: 'PacketOnCloseCalculator'
+          input_stream: 'out'
+          output_stream: 'close_out'
+        }
+      )");
+  tool::AddVectorSink("close_out", &graph_config_, &outputs);
+
+  CalculatorGraph graph_;
+  MP_ASSERT_OK(graph_.Initialize(graph_config_, {}));
+  MP_ASSERT_OK(graph_.StartRun({}));
+
+  auto send_packet = [&graph_](const std::string& input_name, int n) {
+    MP_EXPECT_OK(graph_.AddPacketToInputStream(
+        input_name, MakePacket<int>(n).At(Timestamp(n))));
+  };
+
+  send_packet("in", 1);
+  MP_EXPECT_OK(graph_.WaitUntilIdle());
+  EXPECT_THAT(TimestampValues(outputs), ElementsAre(1));
+
+  send_packet("in", 2);
+  MP_EXPECT_OK(graph_.WaitUntilIdle());
+  EXPECT_THAT(TimestampValues(outputs), ElementsAre(1, 2));
+
+  send_packet("in", 5);
+  MP_EXPECT_OK(graph_.WaitUntilIdle());
+  EXPECT_THAT(TimestampValues(outputs), ElementsAre(1, 2, 5));
+
+  send_packet("in", 15);
+  MP_EXPECT_OK(graph_.WaitUntilIdle());
+  EXPECT_THAT(TimestampValues(outputs), ElementsAre(1, 2, 5, 15));
+
+  MP_EXPECT_OK(graph_.CloseAllInputStreams());
+  MP_EXPECT_OK(graph_.WaitUntilIdle());
+  EXPECT_THAT(TimestampValues(outputs),
+              ElementsAre(1, 2, 5, 15, Timestamp::Max().Value()));
+
+  MP_EXPECT_OK(graph_.WaitUntilDone());
+}
+
+// Demonstrates that downstream calculators won't be blocked by
+// always-empty-LOOP-stream.
+TEST(PreviousLoopbackCalculator, EmptyLoopForever) {
+  std::vector<Packet> outputs;
+  CalculatorGraphConfig graph_config_ =
+      ParseTextProtoOrDie<CalculatorGraphConfig>(R"(
+        input_stream: 'in'
+        node {
+          calculator: 'PreviousLoopbackCalculator'
+          input_stream: 'MAIN:in'
+          input_stream: 'LOOP:previous'
+          input_stream_info: { tag_index: 'LOOP' back_edge: true }
+          output_stream: 'PREV_LOOP:previous'
+        }
+        # This calculator synchronizes its inputs as normal, so it is used
+        # to check that both "in" and "previous" are ready.
+        node {
+          calculator: 'PassThroughCalculator'
+          input_stream: 'in'
+          input_stream: 'previous'
+          output_stream: 'out'
+          output_stream: 'previous2'
+        }
+        node {
+          calculator: 'PacketOnCloseCalculator'
+          input_stream: 'out'
+          output_stream: 'close_out'
+        }
+      )");
+  tool::AddVectorSink("close_out", &graph_config_, &outputs);
+
+  CalculatorGraph graph_;
+  MP_ASSERT_OK(graph_.Initialize(graph_config_, {}));
+  MP_ASSERT_OK(graph_.StartRun({}));
+
+  auto send_packet = [&graph_](const std::string& input_name, int n) {
+    MP_EXPECT_OK(graph_.AddPacketToInputStream(
+        input_name, MakePacket<int>(n).At(Timestamp(n))));
+  };
+
+  for (int main_ts = 0; main_ts < 50; ++main_ts) {
+    send_packet("in", main_ts);
+    MP_EXPECT_OK(graph_.WaitUntilIdle());
+    std::vector<int64> ts_values = TimestampValues(outputs);
+    EXPECT_EQ(ts_values.size(), main_ts + 1);
+    for (int j = 0; j < main_ts + 1; ++j) {
+      EXPECT_EQ(ts_values[j], j);
+    }
+  }
+
+  MP_EXPECT_OK(graph_.CloseAllInputStreams());
+  MP_EXPECT_OK(graph_.WaitUntilIdle());
+  MP_EXPECT_OK(graph_.WaitUntilDone());
+}
+
+class PreviousLoopbackCalculatorProcessingTimestampsTest
+    : public testing::Test {
+ protected:
+  void SetUp() override {
+    CalculatorGraphConfig graph_config =
+        ParseTextProtoOrDie<CalculatorGraphConfig>(R"(
+          input_stream: 'input'
+          input_stream: 'force_main_empty'
+          input_stream: 'force_loop_empty'
+          # Used to indicate "main" timestamp bound updates.
+          node {
+            calculator: 'GateCalculator'
+            input_stream: 'input'
+            input_stream: 'DISALLOW:force_main_empty'
+            output_stream: 'main'
+          }
+          node {
+            calculator: 'PreviousLoopbackCalculator'
+            input_stream: 'MAIN:main'
+            input_stream: 'LOOP:loop'
+            input_stream_info: { tag_index: 'LOOP' back_edge: true }
+            output_stream: 'PREV_LOOP:prev_loop'
+          }
+          node {
+            calculator: 'PassThroughCalculator'
+            input_stream: 'input'
+            input_stream: 'prev_loop'
+            output_stream: 'passed_through_input'
+            output_stream: 'passed_through_prev_loop'
+          }
+          # Used to indicate "loop" timestamp bound updates.
+          node {
+            calculator: 'GateCalculator'
+            input_stream: 'input'
+            input_stream: 'DISALLOW:force_loop_empty'
+            output_stream: 'loop'
+          }
+          node {
+            calculator: 'MakePairCalculator'
+            input_stream: 'passed_through_input'
+            input_stream: 'passed_through_prev_loop'
+            output_stream: 'passed_through_input_and_prev_loop'
+          }
+        )");
+    tool::AddVectorSink("passed_through_input_and_prev_loop", &graph_config,
+                        &output_packets_);
+    MP_ASSERT_OK(graph_.Initialize(graph_config, {}));
+    MP_ASSERT_OK(graph_.StartRun({}));
+  }
+
+  void SendPackets(int timestamp, int input, bool force_main_empty,
+                   bool force_loop_empty) {
+    MP_ASSERT_OK(graph_.AddPacketToInputStream(
+        "input", MakePacket<int>(input).At(Timestamp(timestamp))));
+    MP_ASSERT_OK(graph_.AddPacketToInputStream(
+        "force_main_empty",
+        MakePacket<bool>(force_main_empty).At(Timestamp(timestamp))));
+    MP_ASSERT_OK(graph_.AddPacketToInputStream(
+        "force_loop_empty",
+        MakePacket<bool>(force_loop_empty).At(Timestamp(timestamp))));
+  }
+
+  CalculatorGraph graph_;
+  std::vector<Packet> output_packets_;
+};
+
+TEST_F(PreviousLoopbackCalculatorProcessingTimestampsTest,
+       MultiplePacketsEmptyMainNonEmptyLoop) {
+  SendPackets(/*timestamp=*/1, /*input=*/1, /*force_main_empty=*/true,
+              /*force_loop_empty=*/false);
+  MP_EXPECT_OK(graph_.WaitUntilIdle());
+  EXPECT_THAT(
+      output_packets_,
+      ElementsAre(PairPacket(Timestamp(1), Pair(IntPacket(1), EmptyPacket()))));
+
+  SendPackets(/*timestamp=*/2, /*input=*/2, /*force_main_empty=*/true,
+              /*force_loop_empty=*/false);
+  MP_EXPECT_OK(graph_.WaitUntilIdle());
+  EXPECT_THAT(
+      output_packets_,
+      ElementsAre(PairPacket(Timestamp(1), Pair(IntPacket(1), EmptyPacket())),
+                  PairPacket(Timestamp(2), Pair(IntPacket(2), EmptyPacket()))));
+
+  SendPackets(/*timestamp=*/3, /*input=*/3, /*force_main_empty=*/true,
+              /*force_loop_empty=*/false);
+  MP_EXPECT_OK(graph_.WaitUntilIdle());
+  EXPECT_THAT(
+      output_packets_,
+      ElementsAre(PairPacket(Timestamp(1), Pair(IntPacket(1), EmptyPacket())),
+                  PairPacket(Timestamp(2), Pair(IntPacket(2), EmptyPacket())),
+                  PairPacket(Timestamp(3), Pair(IntPacket(3), EmptyPacket()))));
+
+  SendPackets(/*timestamp=*/5, /*input=*/5, /*force_main_empty=*/true,
+              /*force_loop_empty=*/false);
+  MP_EXPECT_OK(graph_.WaitUntilIdle());
+  EXPECT_THAT(
+      output_packets_,
+      ElementsAre(PairPacket(Timestamp(1), Pair(IntPacket(1), EmptyPacket())),
+                  PairPacket(Timestamp(2), Pair(IntPacket(2), EmptyPacket())),
+                  PairPacket(Timestamp(3), Pair(IntPacket(3), EmptyPacket())),
+                  PairPacket(Timestamp(5), Pair(IntPacket(5), EmptyPacket()))));
+
+  SendPackets(/*timestamp=*/15, /*input=*/15,
+              /*force_main_empty=*/true,
+              /*force_loop_empty=*/false);
+  MP_EXPECT_OK(graph_.WaitUntilIdle());
+  EXPECT_THAT(
+      output_packets_,
+      ElementsAre(
+          PairPacket(Timestamp(1), Pair(IntPacket(1), EmptyPacket())),
+          PairPacket(Timestamp(2), Pair(IntPacket(2), EmptyPacket())),
+          PairPacket(Timestamp(3), Pair(IntPacket(3), EmptyPacket())),
+          PairPacket(Timestamp(5), Pair(IntPacket(5), EmptyPacket())),
+          PairPacket(Timestamp(15), Pair(IntPacket(15), EmptyPacket()))));
+
+  MP_EXPECT_OK(graph_.CloseAllInputStreams());
+  MP_EXPECT_OK(graph_.WaitUntilDone());
+}
+
+TEST_F(PreviousLoopbackCalculatorProcessingTimestampsTest,
+       MultiplePacketsNonEmptyMainEmptyLoop) {
+  SendPackets(/*timestamp=*/1, /*input=*/1,
+              /*force_main_empty=*/false,
+              /*force_loop_empty=*/true);
+  MP_EXPECT_OK(graph_.WaitUntilIdle());
+  EXPECT_THAT(
+      output_packets_,
+      ElementsAre(PairPacket(Timestamp(1), Pair(IntPacket(1), EmptyPacket()))));
+
+  SendPackets(/*timestamp=*/2, /*input=*/2,
+              /*force_main_empty=*/false,
+              /*force_loop_empty=*/true);
+  MP_EXPECT_OK(graph_.WaitUntilIdle());
+  EXPECT_THAT(
+      output_packets_,
+      ElementsAre(PairPacket(Timestamp(1), Pair(IntPacket(1), EmptyPacket())),
+                  PairPacket(Timestamp(2), Pair(IntPacket(2), EmptyPacket()))));
+
+  SendPackets(/*timestamp=*/3, /*input=*/3,
+              /*force_main_empty=*/false,
+              /*force_loop_empty=*/true);
+  MP_EXPECT_OK(graph_.WaitUntilIdle());
+  EXPECT_THAT(
+      output_packets_,
+      ElementsAre(PairPacket(Timestamp(1), Pair(IntPacket(1), EmptyPacket())),
+                  PairPacket(Timestamp(2), Pair(IntPacket(2), EmptyPacket())),
+                  PairPacket(Timestamp(3), Pair(IntPacket(3), EmptyPacket()))));
+
+  SendPackets(/*timestamp=*/5, /*input=*/5,
+              /*force_main_empty=*/false,
+              /*force_loop_empty=*/true);
+  MP_EXPECT_OK(graph_.WaitUntilIdle());
+  EXPECT_THAT(
+      output_packets_,
+      ElementsAre(PairPacket(Timestamp(1), Pair(IntPacket(1), EmptyPacket())),
+                  PairPacket(Timestamp(2), Pair(IntPacket(2), EmptyPacket())),
+                  PairPacket(Timestamp(3), Pair(IntPacket(3), EmptyPacket())),
+                  PairPacket(Timestamp(5), Pair(IntPacket(5), EmptyPacket()))));
+
+  SendPackets(/*timestamp=*/15, /*input=*/15,
+              /*force_main_empty=*/false,
+              /*force_loop_empty=*/true);
+  MP_EXPECT_OK(graph_.WaitUntilIdle());
+  EXPECT_THAT(
+      output_packets_,
+      ElementsAre(
+          PairPacket(Timestamp(1), Pair(IntPacket(1), EmptyPacket())),
+          PairPacket(Timestamp(2), Pair(IntPacket(2), EmptyPacket())),
+          PairPacket(Timestamp(3), Pair(IntPacket(3), EmptyPacket())),
+          PairPacket(Timestamp(5), Pair(IntPacket(5), EmptyPacket())),
+          PairPacket(Timestamp(15), Pair(IntPacket(15), EmptyPacket()))));
+
+  MP_EXPECT_OK(graph_.CloseAllInputStreams());
+  MP_EXPECT_OK(graph_.WaitUntilDone());
+}
+
+TEST_F(PreviousLoopbackCalculatorProcessingTimestampsTest,
+       MultiplePacketsAlteringMainNonEmptyLoop) {
+  SendPackets(/*timestamp=*/1, /*input=*/1,
+              /*force_main_empty=*/false,
+              /*force_loop_empty=*/false);
+  MP_EXPECT_OK(graph_.WaitUntilIdle());
+  EXPECT_THAT(
+      output_packets_,
+      ElementsAre(PairPacket(Timestamp(1), Pair(IntPacket(1), EmptyPacket()))));
+
+  SendPackets(/*timestamp=*/2, /*input=*/2, /*force_main_empty=*/true,
+              /*force_loop_empty=*/false);
+  MP_EXPECT_OK(graph_.WaitUntilIdle());
+  EXPECT_THAT(
+      output_packets_,
+      ElementsAre(PairPacket(Timestamp(1), Pair(IntPacket(1), EmptyPacket())),
+                  PairPacket(Timestamp(2), Pair(IntPacket(2), EmptyPacket()))));
+
+  SendPackets(/*timestamp=*/3, /*input=*/3,
+              /*force_main_empty=*/false,
+              /*force_loop_empty=*/false);
+  MP_EXPECT_OK(graph_.WaitUntilIdle());
+  EXPECT_THAT(
+      output_packets_,
+      ElementsAre(PairPacket(Timestamp(1), Pair(IntPacket(1), EmptyPacket())),
+                  PairPacket(Timestamp(2), Pair(IntPacket(2), EmptyPacket())),
+                  PairPacket(Timestamp(3), Pair(IntPacket(3), IntPacket(1)))));
+
+  SendPackets(/*timestamp=*/5, /*input=*/5,
+              /*force_main_empty=*/false,
+              /*force_loop_empty=*/false);
+  MP_EXPECT_OK(graph_.WaitUntilIdle());
+  EXPECT_THAT(
+      output_packets_,
+      ElementsAre(PairPacket(Timestamp(1), Pair(IntPacket(1), EmptyPacket())),
+                  PairPacket(Timestamp(2), Pair(IntPacket(2), EmptyPacket())),
+                  PairPacket(Timestamp(3), Pair(IntPacket(3), IntPacket(1))),
+                  PairPacket(Timestamp(5), Pair(IntPacket(5), IntPacket(3)))));
+
+  SendPackets(/*timestamp=*/15, /*input=*/15,
+              /*force_main_empty=*/true,
+              /*force_loop_empty=*/false);
+  MP_EXPECT_OK(graph_.WaitUntilIdle());
+  EXPECT_THAT(
+      output_packets_,
+      ElementsAre(
+          PairPacket(Timestamp(1), Pair(IntPacket(1), EmptyPacket())),
+          PairPacket(Timestamp(2), Pair(IntPacket(2), EmptyPacket())),
+          PairPacket(Timestamp(3), Pair(IntPacket(3), IntPacket(1))),
+          PairPacket(Timestamp(5), Pair(IntPacket(5), IntPacket(3))),
+          PairPacket(Timestamp(15), Pair(IntPacket(15), EmptyPacket()))));
+
+  MP_EXPECT_OK(graph_.CloseAllInputStreams());
+  MP_EXPECT_OK(graph_.WaitUntilDone());
+}
+
+TEST_F(PreviousLoopbackCalculatorProcessingTimestampsTest,
+       MultiplePacketsNonEmptyMainAlteringLoop) {
+  SendPackets(/*timestamp=*/1, /*input=*/1,
+              /*force_main_empty=*/false,
+              /*force_loop_empty=*/false);
+  MP_EXPECT_OK(graph_.WaitUntilIdle());
+  EXPECT_THAT(
+      output_packets_,
+      ElementsAre(PairPacket(Timestamp(1), Pair(IntPacket(1), EmptyPacket()))));
+
+  SendPackets(/*timestamp=*/2, /*input=*/2,
+              /*force_main_empty=*/false,
+              /*force_loop_empty=*/true);
+  MP_EXPECT_OK(graph_.WaitUntilIdle());
+  EXPECT_THAT(
+      output_packets_,
+      ElementsAre(PairPacket(Timestamp(1), Pair(IntPacket(1), EmptyPacket())),
+                  PairPacket(Timestamp(2), Pair(IntPacket(2), IntPacket(1)))));
+
+  SendPackets(/*timestamp=*/3, /*input=*/3,
+              /*force_main_empty=*/false,
+              /*force_loop_empty=*/false);
+  MP_EXPECT_OK(graph_.WaitUntilIdle());
+  EXPECT_THAT(
+      output_packets_,
+      ElementsAre(PairPacket(Timestamp(1), Pair(IntPacket(1), EmptyPacket())),
+                  PairPacket(Timestamp(2), Pair(IntPacket(2), IntPacket(1))),
+                  PairPacket(Timestamp(3), Pair(IntPacket(3), EmptyPacket()))));
+
+  SendPackets(/*timestamp=*/5, /*input=*/5,
+              /*force_main_empty=*/false,
+              /*force_loop_empty=*/true);
+  MP_EXPECT_OK(graph_.WaitUntilIdle());
+  EXPECT_THAT(
+      output_packets_,
+      ElementsAre(PairPacket(Timestamp(1), Pair(IntPacket(1), EmptyPacket())),
+                  PairPacket(Timestamp(2), Pair(IntPacket(2), IntPacket(1))),
+                  PairPacket(Timestamp(3), Pair(IntPacket(3), EmptyPacket())),
+                  PairPacket(Timestamp(5), Pair(IntPacket(5), IntPacket(3)))));
+
+  SendPackets(/*timestamp=*/15, /*input=*/15,
+              /*force_main_empty=*/false,
+              /*force_loop_empty=*/false);
+  MP_EXPECT_OK(graph_.WaitUntilIdle());
+  EXPECT_THAT(
+      output_packets_,
+      ElementsAre(
+          PairPacket(Timestamp(1), Pair(IntPacket(1), EmptyPacket())),
+          PairPacket(Timestamp(2), Pair(IntPacket(2), IntPacket(1))),
+          PairPacket(Timestamp(3), Pair(IntPacket(3), EmptyPacket())),
+          PairPacket(Timestamp(5), Pair(IntPacket(5), IntPacket(3))),
+          PairPacket(Timestamp(15), Pair(IntPacket(15), EmptyPacket()))));
+
+  MP_EXPECT_OK(graph_.CloseAllInputStreams());
+  MP_EXPECT_OK(graph_.WaitUntilDone());
+}
+
+TEST_F(PreviousLoopbackCalculatorProcessingTimestampsTest,
+       MultiplePacketsCheckIfLastCorrectAlteringMainAlteringLoop) {
+  int num_packets = 1000;
+  for (int i = 0; i < num_packets; ++i) {
+    bool force_main_empty = i % 3 == 0 ? true : false;
+    bool force_loop_empty = i % 2 == 0 ? true : false;
+    SendPackets(/*timestamp=*/i + 1, /*input=*/i + 1, force_main_empty,
+                force_loop_empty);
+  }
+  SendPackets(/*timestamp=*/num_packets + 1,
+              /*input=*/num_packets + 1, /*force_main_empty=*/false,
+              /*force_loop_empty=*/false);
+  SendPackets(/*timestamp=*/num_packets + 2,
+              /*input=*/num_packets + 2, /*force_main_empty=*/false,
+              /*force_loop_empty=*/false);
+
+  MP_EXPECT_OK(graph_.WaitUntilIdle());
+  ASSERT_FALSE(output_packets_.empty());
+  EXPECT_THAT(
+      output_packets_.back(),
+      PairPacket(Timestamp(num_packets + 2),
+                 Pair(IntPacket(num_packets + 2), IntPacket(num_packets + 1))));
+
+  MP_EXPECT_OK(graph_.CloseAllInputStreams());
+  MP_EXPECT_OK(graph_.WaitUntilDone());
+}
+
+// Similar to GateCalculator, but it doesn't propagate timestamp bound updates.
+class DroppingGateCalculator : public CalculatorBase {
+ public:
+  static ::mediapipe::Status GetContract(CalculatorContract* cc) {
+    cc->Inputs().Index(0).SetAny();
+    cc->Inputs().Tag("DISALLOW").Set<bool>();
+    cc->Outputs().Index(0).SetSameAs(&cc->Inputs().Index(0));
+    return ::mediapipe::OkStatus();
+  }
+
+  ::mediapipe::Status Process(CalculatorContext* cc) final {
+    if (!cc->Inputs().Index(0).IsEmpty() &&
+        !cc->Inputs().Tag("DISALLOW").Get<bool>()) {
+      cc->Outputs().Index(0).AddPacket(cc->Inputs().Index(0).Value());
+    }
+    return ::mediapipe::OkStatus();
+  }
+};
+REGISTER_CALCULATOR(DroppingGateCalculator);
+
+// Tests PreviousLoopbackCalculator in cases when there are no "LOOP" timestamp
+// bound updates and non-empty packets for a while and the aforementioned start
+// to arrive at some point. So, "PREV_LOOP" is delayed for a couple of inputs.
+class PreviousLoopbackCalculatorDelayBehaviorTest : public testing::Test {
+ protected:
+  void SetUp() override {
+    CalculatorGraphConfig graph_config =
+        ParseTextProtoOrDie<CalculatorGraphConfig>(R"(
+          input_stream: 'input'
+          # Drops "loop" when set to "true", delaying output of prev_loop, hence
+          # delaying output of the graph.
+          input_stream: 'delay_next_output'
+          node {
+            calculator: 'PreviousLoopbackCalculator'
+            input_stream: 'MAIN:input'
+            input_stream: 'LOOP:loop'
+            input_stream_info: { tag_index: 'LOOP' back_edge: true }
+            output_stream: 'PREV_LOOP:prev_loop'
+          }
+          node {
+            calculator: 'PassThroughCalculator'
+            input_stream: 'input'
+            input_stream: 'prev_loop'
+            output_stream: 'passed_through_input'
+            output_stream: 'passed_through_prev_loop'
+          }
+          node {
+            calculator: 'DroppingGateCalculator'
+            input_stream: 'input'
+            input_stream: 'DISALLOW:delay_next_output'
+            output_stream: 'loop'
+          }
+          node {
+            calculator: 'MakePairCalculator'
+            input_stream: 'passed_through_input'
+            input_stream: 'passed_through_prev_loop'
+            output_stream: 'passed_through_input_and_prev_loop'
+          }
+        )");
+    tool::AddVectorSink("passed_through_input_and_prev_loop", &graph_config,
+                        &output_packets_);
+    MP_ASSERT_OK(graph_.Initialize(graph_config, {}));
+    MP_ASSERT_OK(graph_.StartRun({}));
+  }
+
+  void SendPackets(int timestamp, int input, bool delay_next_output) {
+    MP_ASSERT_OK(graph_.AddPacketToInputStream(
+        "input", MakePacket<int>(input).At(Timestamp(timestamp))));
+    MP_ASSERT_OK(graph_.AddPacketToInputStream(
+        "delay_next_output",
+        MakePacket<bool>(delay_next_output).At(Timestamp(timestamp))));
+  }
+
+  CalculatorGraph graph_;
+  std::vector<Packet> output_packets_;
+};
+
+TEST_F(PreviousLoopbackCalculatorDelayBehaviorTest, MultipleDelayedOutputs) {
+  SendPackets(/*timestamp=*/1, /*input=*/1, /*delay_next_output=*/true);
+  MP_EXPECT_OK(graph_.WaitUntilIdle());
+  EXPECT_THAT(
+      output_packets_,
+      ElementsAre(PairPacket(Timestamp(1), Pair(IntPacket(1), EmptyPacket()))));
+
+  SendPackets(/*timestamp=*/2, /*input=*/2, /*delay_next_output=*/true);
+  MP_EXPECT_OK(graph_.WaitUntilIdle());
+  EXPECT_THAT(
+      output_packets_,
+      ElementsAre(PairPacket(Timestamp(1), Pair(IntPacket(1), EmptyPacket()))));
+
+  SendPackets(/*timestamp=*/3, /*input=*/3, /*delay_next_output=*/true);
+  MP_EXPECT_OK(graph_.WaitUntilIdle());
+  EXPECT_THAT(
+      output_packets_,
+      ElementsAre(PairPacket(Timestamp(1), Pair(IntPacket(1), EmptyPacket()))));
+
+  SendPackets(/*timestamp=*/5, /*input=*/5, /*delay_next_output=*/false);
+  MP_EXPECT_OK(graph_.WaitUntilIdle());
+  EXPECT_THAT(
+      output_packets_,
+      ElementsAre(PairPacket(Timestamp(1), Pair(IntPacket(1), EmptyPacket())),
+                  PairPacket(Timestamp(2), Pair(IntPacket(2), EmptyPacket())),
+                  PairPacket(Timestamp(3), Pair(IntPacket(3), EmptyPacket())),
+                  PairPacket(Timestamp(5), Pair(IntPacket(5), EmptyPacket()))));
+
+  SendPackets(/*timestamp=*/15, /*input=*/15, /*delay_next_output=*/false);
+  MP_EXPECT_OK(graph_.WaitUntilIdle());
+  EXPECT_THAT(
+      output_packets_,
+      ElementsAre(
+          PairPacket(Timestamp(1), Pair(IntPacket(1), EmptyPacket())),
+          PairPacket(Timestamp(2), Pair(IntPacket(2), EmptyPacket())),
+          PairPacket(Timestamp(3), Pair(IntPacket(3), EmptyPacket())),
+          PairPacket(Timestamp(5), Pair(IntPacket(5), EmptyPacket())),
+          PairPacket(Timestamp(15), Pair(IntPacket(15), IntPacket(5)))));
+
+  MP_EXPECT_OK(graph_.CloseAllInputStreams());
+  MP_EXPECT_OK(graph_.WaitUntilDone());
+}
+
+TEST_F(PreviousLoopbackCalculatorDelayBehaviorTest,
+       NonDelayedOutputFollowedByMultipleDelayedOutputs) {
+  SendPackets(/*timestamp=*/1, /*input=*/1, /*delay_next_output=*/false);
+  MP_EXPECT_OK(graph_.WaitUntilIdle());
+  EXPECT_THAT(
+      output_packets_,
+      ElementsAre(PairPacket(Timestamp(1), Pair(IntPacket(1), EmptyPacket()))));
+
+  SendPackets(/*timestamp=*/2, /*input=*/2, /*delay_next_output=*/true);
+  MP_EXPECT_OK(graph_.WaitUntilIdle());
+  EXPECT_THAT(
+      output_packets_,
+      ElementsAre(PairPacket(Timestamp(1), Pair(IntPacket(1), EmptyPacket())),
+                  PairPacket(Timestamp(2), Pair(IntPacket(2), IntPacket(1)))));
+
+  SendPackets(/*timestamp=*/3, /*input=*/3, /*delay_next_output=*/true);
+  MP_EXPECT_OK(graph_.WaitUntilIdle());
+  EXPECT_THAT(
+      output_packets_,
+      ElementsAre(PairPacket(Timestamp(1), Pair(IntPacket(1), EmptyPacket())),
+                  PairPacket(Timestamp(2), Pair(IntPacket(2), IntPacket(1)))));
+
+  SendPackets(/*timestamp=*/5, /*input=*/5, /*delay_next_output=*/false);
+  MP_EXPECT_OK(graph_.WaitUntilIdle());
+  EXPECT_THAT(
+      output_packets_,
+      ElementsAre(PairPacket(Timestamp(1), Pair(IntPacket(1), EmptyPacket())),
+                  PairPacket(Timestamp(2), Pair(IntPacket(2), IntPacket(1))),
+                  PairPacket(Timestamp(3), Pair(IntPacket(3), EmptyPacket())),
+                  PairPacket(Timestamp(5), Pair(IntPacket(5), EmptyPacket()))));
+
+  SendPackets(/*timestamp=*/15, /*input=*/15, /*delay_next_output=*/false);
+  MP_EXPECT_OK(graph_.WaitUntilIdle());
+  EXPECT_THAT(
+      output_packets_,
+      ElementsAre(
+          PairPacket(Timestamp(1), Pair(IntPacket(1), EmptyPacket())),
+          PairPacket(Timestamp(2), Pair(IntPacket(2), IntPacket(1))),
+          PairPacket(Timestamp(3), Pair(IntPacket(3), EmptyPacket())),
+          PairPacket(Timestamp(5), Pair(IntPacket(5), EmptyPacket())),
+          PairPacket(Timestamp(15), Pair(IntPacket(15), IntPacket(5)))));
+
+  MP_EXPECT_OK(graph_.CloseAllInputStreams());
+  MP_EXPECT_OK(graph_.WaitUntilDone());
 }

 }  // anonymous namespace
@@ -124,7 +124,7 @@ TEST(QuantizeFloatVectorCalculatorTest, TestEmptyVector) {
      ->Tag("FLOAT_VECTOR")
      .packets.push_back(
          MakePacket<std::vector<float>>(empty_vector).At(Timestamp(0)));
-  MEDIAPIPE_ASSERT_OK(runner.Run());
+  MP_ASSERT_OK(runner.Run());
  const std::vector<Packet>& outputs = runner.Outputs().Tag("ENCODED").packets;
  EXPECT_EQ(1, outputs.size());
  EXPECT_TRUE(outputs[0].Get<std::string>().empty());
@@ -150,7 +150,7 @@ TEST(QuantizeFloatVectorCalculatorTest, TestNonEmptyVector) {
      ->Tag("FLOAT_VECTOR")
      .packets.push_back(
          MakePacket<std::vector<float>>(vector).At(Timestamp(0)));
-  MEDIAPIPE_ASSERT_OK(runner.Run());
+  MP_ASSERT_OK(runner.Run());
  const std::vector<Packet>& outputs = runner.Outputs().Tag("ENCODED").packets;
  EXPECT_EQ(1, outputs.size());
  const std::string& result = outputs[0].Get<std::string>();
@@ -188,7 +188,7 @@ TEST(QuantizeFloatVectorCalculatorTest, TestSaturation) {
      ->Tag("FLOAT_VECTOR")
      .packets.push_back(
          MakePacket<std::vector<float>>(vector).At(Timestamp(0)));
-  MEDIAPIPE_ASSERT_OK(runner.Run());
+  MP_ASSERT_OK(runner.Run());
  const std::vector<Packet>& outputs = runner.Outputs().Tag("ENCODED").packets;
  EXPECT_EQ(1, outputs.size());
  const std::string& result = outputs[0].Get<std::string>();
@@ -38,7 +38,7 @@ TEST(SequenceShiftCalculatorTest, ZeroShift) {
      "[mediapipe.SequenceShiftCalculatorOptions.ext]: { packet_offset: 0 }", 1,
      1, 0);
  AddPackets(&runner);
-  MEDIAPIPE_ASSERT_OK(runner.Run());
+  MP_ASSERT_OK(runner.Run());
  const std::vector<Packet>& input_packets =
      runner.MutableInputs()->Index(0).packets;
  const std::vector<Packet>& output_packets = runner.Outputs().Index(0).packets;
@@ -59,7 +59,7 @@ TEST(SequenceShiftCalculatorTest, PositiveShift) {
      "[mediapipe.SequenceShiftCalculatorOptions.ext]: { packet_offset: 3 }", 1,
      1, 0);
  AddPackets(&runner);
-  MEDIAPIPE_ASSERT_OK(runner.Run());
+  MP_ASSERT_OK(runner.Run());
  const std::vector<Packet>& input_packets =
      runner.MutableInputs()->Index(0).packets;
  const std::vector<Packet>& output_packets = runner.Outputs().Index(0).packets;
@@ -83,7 +83,7 @@ TEST(SequenceShiftCalculatorTest, NegativeShift) {
      "[mediapipe.SequenceShiftCalculatorOptions.ext]: { packet_offset: -2 }",
      1, 1, 0);
  AddPackets(&runner);
-  MEDIAPIPE_ASSERT_OK(runner.Run());
+  MP_ASSERT_OK(runner.Run());
  const std::vector<Packet>& input_packets =
      runner.MutableInputs()->Index(0).packets;
  const std::vector<Packet>& output_packets = runner.Outputs().Index(0).packets;
@@ -0,0 +1,161 @@
+// Copyright 2019 The MediaPipe Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include <map>
+#include <memory>
+#include <set>
+#include <string>
+
+#include "mediapipe/framework/calculator_framework.h"
+#include "mediapipe/framework/port/logging.h"
+#include "mediapipe/framework/port/ret_check.h"
+#include "mediapipe/framework/port/status.h"
+
+namespace mediapipe {
+
+using mediapipe::PacketTypeSet;
+using mediapipe::Timestamp;
+
+namespace {
+
+constexpr char kTagAtPreStream[] = "AT_PRESTREAM";
+constexpr char kTagAtPostStream[] = "AT_POSTSTREAM";
+constexpr char kTagAtZero[] = "AT_ZERO";
+constexpr char kTagAtTick[] = "AT_TICK";
+constexpr char kTagTick[] = "TICK";
+
+static std::map<std::string, Timestamp>* kTimestampMap = []() {
+  auto* res = new std::map<std::string, Timestamp>();
+  res->emplace(kTagAtPreStream, Timestamp::PreStream());
+  res->emplace(kTagAtPostStream, Timestamp::PostStream());
+  res->emplace(kTagAtZero, Timestamp(0));
+  res->emplace(kTagAtTick, Timestamp::Unset());
+  return res;
+}();
+
+template <typename CC>
+std::string GetOutputTag(const CC& cc) {
+  // Single output tag only is required by contract.
+  return *cc.Outputs().GetTags().begin();
+}
+
+}  // namespace
+
+// Outputs side packet(s) in corresponding output stream(s) with a particular
+// timestamp, depending on the tag used to define output stream(s). (One tag can
+// be used only.)
+//
+// Valid tags are AT_PRESTREAM, AT_POSTSTREAM, AT_ZERO and AT_TICK and
+// corresponding timestamps are Timestamp::PreStream(), Timestamp::PostStream(),
+// Timestamp(0) and timestamp of a packet received in TICK input.
+//
+// Examples:
+// node {
+//   calculator: "SidePacketToStreamCalculator"
+//   input_side_packet: "side_packet"
+//   output_stream: "AT_PRESTREAM:packet"
+// }
+//
+// node {
+//   calculator: "SidePacketToStreamCalculator"
+//   input_stream: "TICK:tick"
+//   input_side_packet: "side_packet"
+//   output_stream: "AT_TICK:packet"
+// }
+class SidePacketToStreamCalculator : public CalculatorBase {
+ public:
+  SidePacketToStreamCalculator() = default;
+  ~SidePacketToStreamCalculator() override = default;
+
+  static ::mediapipe::Status GetContract(CalculatorContract* cc);
+  ::mediapipe::Status Open(CalculatorContext* cc) override;
+  ::mediapipe::Status Process(CalculatorContext* cc) override;
+  ::mediapipe::Status Close(CalculatorContext* cc) override;
+
+ private:
+  bool is_tick_processing_ = false;
+  std::string output_tag_;
+};
+REGISTER_CALCULATOR(SidePacketToStreamCalculator);
+
+::mediapipe::Status SidePacketToStreamCalculator::GetContract(
+    CalculatorContract* cc) {
+  const auto& tags = cc->Outputs().GetTags();
+  RET_CHECK(tags.size() == 1 && kTimestampMap->count(*tags.begin()) == 1)
+      << "Only one of AT_PRESTREAM, AT_POSTSTREAM, AT_ZERO and AT_TICK tags is "
+         "allowed and required to specify output stream(s).";
+  RET_CHECK(
+      (cc->Outputs().HasTag(kTagAtTick) && cc->Inputs().HasTag(kTagTick)) ||
+      (!cc->Outputs().HasTag(kTagAtTick) && !cc->Inputs().HasTag(kTagTick)))
+      << "Either both of TICK and AT_TICK should be used or none of them.";
+  const std::string output_tag = GetOutputTag(*cc);
+  const int num_entries = cc->Outputs().NumEntries(output_tag);
+  RET_CHECK_EQ(num_entries, cc->InputSidePackets().NumEntries())
+      << "Same number of input side packets and output streams is required.";
+  for (int i = 0; i < num_entries; ++i) {
+    cc->InputSidePackets().Index(i).SetAny();
+    cc->Outputs()
+        .Get(output_tag, i)
+        .SetSameAs(cc->InputSidePackets().Index(i).GetSameAs());
+  }
+
+  if (cc->Inputs().HasTag(kTagTick)) {
+    cc->Inputs().Tag(kTagTick).SetAny();
+  }
+
+  return ::mediapipe::OkStatus();
+}
+
+::mediapipe::Status SidePacketToStreamCalculator::Open(CalculatorContext* cc) {
+  output_tag_ = GetOutputTag(*cc);
+  if (cc->Inputs().HasTag(kTagTick)) {
+    is_tick_processing_ = true;
+    // Set offset, so output timestamp bounds are updated in response to TICK
+    // timestamp bound update.
+    cc->SetOffset(TimestampDiff(0));
+  }
+  return ::mediapipe::OkStatus();
+}
+
+::mediapipe::Status SidePacketToStreamCalculator::Process(
+    CalculatorContext* cc) {
+  if (is_tick_processing_) {
+    // TICK input is guaranteed to be non-empty, as it's the only input stream
+    // for this calculator.
+    const auto& timestamp = cc->Inputs().Tag(kTagTick).Value().Timestamp();
+    for (int i = 0; i < cc->Outputs().NumEntries(output_tag_); ++i) {
+      cc->Outputs()
+          .Get(output_tag_, i)
+          .AddPacket(cc->InputSidePackets().Index(i).At(timestamp));
+    }
+
+    return ::mediapipe::OkStatus();
+  }
+
+  return ::mediapipe::tool::StatusStop();
+}
+
+::mediapipe::Status SidePacketToStreamCalculator::Close(CalculatorContext* cc) {
+  if (!cc->Outputs().HasTag(kTagAtTick)) {
+    const auto& timestamp = kTimestampMap->at(output_tag_);
+    for (int i = 0; i < cc->Outputs().NumEntries(output_tag_); ++i) {
+      cc->Outputs()
+          .Get(output_tag_, i)
+          .AddPacket(cc->InputSidePackets().Index(i).At(timestamp));
+    }
+  }
+  return ::mediapipe::OkStatus();
+}
+
+}  // namespace mediapipe
@@ -0,0 +1,275 @@
+// Copyright 2020 The MediaPipe Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include <string>
+#include <vector>
+
+#include "absl/memory/memory.h"
+#include "absl/strings/match.h"
+#include "absl/strings/str_replace.h"
+#include "absl/strings/string_view.h"
+#include "mediapipe/framework/calculator_framework.h"
+#include "mediapipe/framework/port/gtest.h"
+#include "mediapipe/framework/port/integral_types.h"
+#include "mediapipe/framework/port/parse_text_proto.h"
+#include "mediapipe/framework/port/status.h"
+#include "mediapipe/framework/port/status_matchers.h"
+#include "mediapipe/framework/tool/options_util.h"
+
+namespace mediapipe {
+namespace {
+
+TEST(SidePacketToStreamCalculator, WrongConfig_MissingTick) {
+  CalculatorGraphConfig graph_config =
+      ParseTextProtoOrDie<CalculatorGraphConfig>(
+          R"(
+            input_stream: "tick"
+            input_side_packet: "side_packet"
+            output_stream: "packet"
+            node {
+              calculator: "SidePacketToStreamCalculator"
+              input_side_packet: "side_packet"
+              output_stream: "AT_TICK:packet"
+            }
+          )");
+  CalculatorGraph graph;
+  auto status = graph.Initialize(graph_config);
+  EXPECT_FALSE(status.ok());
+  EXPECT_PRED2(
+      absl::StrContains, status.message(),
+      "Either both of TICK and AT_TICK should be used or none of them.");
+}
+
+TEST(SidePacketToStreamCalculator, WrongConfig_NonExistentTag) {
+  CalculatorGraphConfig graph_config =
+      ParseTextProtoOrDie<CalculatorGraphConfig>(
+          R"(
+            input_stream: "tick"
+            input_side_packet: "side_packet"
+            output_stream: "packet"
+            node {
+              calculator: "SidePacketToStreamCalculator"
+              input_side_packet: "side_packet"
+              output_stream: "DOES_NOT_EXIST:packet"
+            }
+          )");
+  CalculatorGraph graph;
+  auto status = graph.Initialize(graph_config);
+  EXPECT_FALSE(status.ok());
+  EXPECT_PRED2(absl::StrContains, status.message(),
+               "Only one of AT_PRESTREAM, AT_POSTSTREAM, AT_ZERO and AT_TICK "
+               "tags is allowed and required to specify output stream(s).");
+}
+
+TEST(SidePacketToStreamCalculator, WrongConfig_MixedTags) {
+  CalculatorGraphConfig graph_config =
+      ParseTextProtoOrDie<CalculatorGraphConfig>(
+          R"(
+            input_stream: "tick"
+            input_side_packet: "side_packet0"
+            input_side_packet: "side_packet1"
+            node {
+              calculator: "SidePacketToStreamCalculator"
+              input_side_packet: "side_packet0"
+              input_side_packet: "side_packet1"
+              output_stream: "AT_TICK:packet0"
+              output_stream: "AT_PRE_STREAM:packet1"
+            }
+          )");
+  CalculatorGraph graph;
+  auto status = graph.Initialize(graph_config);
+  EXPECT_FALSE(status.ok());
+  EXPECT_PRED2(absl::StrContains, status.message(),
+               "Only one of AT_PRESTREAM, AT_POSTSTREAM, AT_ZERO and AT_TICK "
+               "tags is allowed and required to specify output stream(s).");
+}
+
+TEST(SidePacketToStreamCalculator, WrongConfig_NotEnoughSidePackets) {
+  CalculatorGraphConfig graph_config =
+      ParseTextProtoOrDie<CalculatorGraphConfig>(
+          R"(
+            input_side_packet: "side_packet0"
+            input_side_packet: "side_packet1"
+            node {
+              calculator: "SidePacketToStreamCalculator"
+              input_side_packet: "side_packet0"
+              output_stream: "AT_PRESTREAM:0:packet0"
+              output_stream: "AT_PRESTREAM:1:packet1"
+            }
+          )");
+  CalculatorGraph graph;
+  auto status = graph.Initialize(graph_config);
+  EXPECT_FALSE(status.ok());
+  EXPECT_PRED2(
+      absl::StrContains, status.message(),
+      "Same number of input side packets and output streams is required.");
+}
+
+TEST(SidePacketToStreamCalculator, WrongConfig_NotEnoughOutputStreams) {
+  CalculatorGraphConfig graph_config =
+      ParseTextProtoOrDie<CalculatorGraphConfig>(
+          R"(
+            input_side_packet: "side_packet0"
+            input_side_packet: "side_packet1"
+            node {
+              calculator: "SidePacketToStreamCalculator"
+              input_side_packet: "side_packet0"
+              input_side_packet: "side_packet1"
+              output_stream: "AT_PRESTREAM:packet0"
+            }
+          )");
+  CalculatorGraph graph;
+  auto status = graph.Initialize(graph_config);
+  EXPECT_FALSE(status.ok());
+  EXPECT_PRED2(
+      absl::StrContains, status.message(),
+      "Same number of input side packets and output streams is required.");
+}
+
+void DoTestNonAtTickOutputTag(absl::string_view tag,
+                              Timestamp expected_timestamp) {
+  CalculatorGraphConfig graph_config =
+      ParseTextProtoOrDie<CalculatorGraphConfig>(absl::StrReplaceAll(
+          R"(
+            input_side_packet: "side_packet"
+            output_stream: "packet"
+            node {
+              calculator: "SidePacketToStreamCalculator"
+              input_side_packet: "side_packet"
+              output_stream: "$tag:packet"
+            }
+          )",
+          {{"$tag", tag}}));
+  CalculatorGraph graph;
+  MP_ASSERT_OK(graph.Initialize(graph_config));
+  const int expected_value = 10;
+  std::vector<Packet> output_packets;
+  MP_ASSERT_OK(graph.ObserveOutputStream(
+      "packet", [&output_packets](const Packet& packet) {
+        output_packets.push_back(packet);
+        return ::mediapipe::OkStatus();
+      }));
+  MP_ASSERT_OK(
+      graph.StartRun({{"side_packet", MakePacket<int>(expected_value)}}));
+  MP_ASSERT_OK(graph.WaitForObservedOutput());
+
+  ASSERT_FALSE(output_packets.empty());
+  EXPECT_EQ(expected_timestamp, output_packets.back().Timestamp());
+  EXPECT_EQ(expected_value, output_packets.back().Get<int>());
+}
+
+TEST(SidePacketToStreamCalculator, NoAtTickOutputTags) {
+  DoTestNonAtTickOutputTag("AT_PRESTREAM", Timestamp::PreStream());
+  DoTestNonAtTickOutputTag("AT_POSTSTREAM", Timestamp::PostStream());
+  DoTestNonAtTickOutputTag("AT_ZERO", Timestamp(0));
+}
+
+TEST(SidePacketToStreamCalculator, AtTick) {
+  CalculatorGraphConfig graph_config =
+      ParseTextProtoOrDie<CalculatorGraphConfig>(
+          R"(
+            input_stream: "tick"
+            input_side_packet: "side_packet"
+            output_stream: "packet"
+            node {
+              calculator: "SidePacketToStreamCalculator"
+              input_stream: "TICK:tick"
+              input_side_packet: "side_packet"
+              output_stream: "AT_TICK:packet"
+            }
+          )");
+  std::vector<Packet> output_packets;
+  tool::AddVectorSink("packet", &graph_config, &output_packets);
+  CalculatorGraph graph;
+
+  MP_ASSERT_OK(graph.Initialize(graph_config));
+  const int expected_value = 20;
+  MP_ASSERT_OK(
+      graph.StartRun({{"side_packet", MakePacket<int>(expected_value)}}));
+
+  auto tick_and_verify = [&graph, &output_packets,
+                          expected_value](int at_timestamp) {
+    MP_ASSERT_OK(graph.AddPacketToInputStream(
+        "tick",
+        MakePacket<int>(/*doesn't matter*/ 1).At(Timestamp(at_timestamp))));
+    MP_ASSERT_OK(graph.WaitUntilIdle());
+
+    ASSERT_FALSE(output_packets.empty());
+    EXPECT_EQ(Timestamp(at_timestamp), output_packets.back().Timestamp());
+    EXPECT_EQ(expected_value, output_packets.back().Get<int>());
+  };
+
+  tick_and_verify(/*at_timestamp=*/0);
+  tick_and_verify(/*at_timestamp=*/1);
+  tick_and_verify(/*at_timestamp=*/128);
+  tick_and_verify(/*at_timestamp=*/1024);
+  tick_and_verify(/*at_timestamp=*/1025);
+}
+
+TEST(SidePacketToStreamCalculator, AtTick_MultipleSidePackets) {
+  CalculatorGraphConfig graph_config =
+      ParseTextProtoOrDie<CalculatorGraphConfig>(
+          R"(
+            input_stream: "tick"
+            input_side_packet: "side_packet0"
+            input_side_packet: "side_packet1"
+            output_stream: "packet0"
+            output_stream: "packet1"
+            node {
+              calculator: "SidePacketToStreamCalculator"
+              input_stream: "TICK:tick"
+              input_side_packet: "side_packet0"
+              input_side_packet: "side_packet1"
+              output_stream: "AT_TICK:0:packet0"
+              output_stream: "AT_TICK:1:packet1"
+            }
+          )");
+  std::vector<Packet> output_packets0;
+  tool::AddVectorSink("packet0", &graph_config, &output_packets0);
+  std::vector<Packet> output_packets1;
+  tool::AddVectorSink("packet1", &graph_config, &output_packets1);
+  CalculatorGraph graph;
+
+  MP_ASSERT_OK(graph.Initialize(graph_config));
+  const int expected_value0 = 20;
+  const int expected_value1 = 128;
+  MP_ASSERT_OK(
+      graph.StartRun({{"side_packet0", MakePacket<int>(expected_value0)},
+                      {"side_packet1", MakePacket<int>(expected_value1)}}));
+
+  auto tick_and_verify = [&graph, &output_packets0, &output_packets1,
+                          expected_value0, expected_value1](int at_timestamp) {
+    MP_ASSERT_OK(graph.AddPacketToInputStream(
+        "tick",
+        MakePacket<int>(/*doesn't matter*/ 1).At(Timestamp(at_timestamp))));
+    MP_ASSERT_OK(graph.WaitUntilIdle());
+
+    ASSERT_FALSE(output_packets0.empty());
+    ASSERT_FALSE(output_packets1.empty());
+
+    EXPECT_EQ(Timestamp(at_timestamp), output_packets0.back().Timestamp());
+    EXPECT_EQ(expected_value0, output_packets0.back().Get<int>());
+    EXPECT_EQ(Timestamp(at_timestamp), output_packets1.back().Timestamp());
+    EXPECT_EQ(expected_value1, output_packets1.back().Get<int>());
+  };
+
+  tick_and_verify(/*at_timestamp=*/0);
+  tick_and_verify(/*at_timestamp=*/1);
+  tick_and_verify(/*at_timestamp=*/128);
+  tick_and_verify(/*at_timestamp=*/1024);
+  tick_and_verify(/*at_timestamp=*/1025);
+}
+
+}  // namespace
+}  // namespace mediapipe
@@ -16,8 +16,16 @@

 #include <vector>

+#include "mediapipe/framework/formats/detection.pb.h"
+#include "mediapipe/framework/formats/landmark.pb.h"
+#include "mediapipe/framework/formats/matrix.h"
+#include "mediapipe/framework/formats/rect.pb.h"
 #include "tensorflow/lite/interpreter.h"

+#if !defined(MEDIAPIPE_DISABLE_GL_COMPUTE)
+#include "tensorflow/lite/delegates/gpu/gl/gl_buffer.h"
+#endif  //  !MEDIAPIPE_DISABLE_GPU
+
 namespace mediapipe {

 // Example config:
@@ -34,7 +42,33 @@ namespace mediapipe {
 //     }
 //   }
 // }
-typedef SplitVectorCalculator<TfLiteTensor> SplitTfLiteTensorVectorCalculator;
+typedef SplitVectorCalculator<TfLiteTensor, false>
+    SplitTfLiteTensorVectorCalculator;
 REGISTER_CALCULATOR(SplitTfLiteTensorVectorCalculator);

+typedef SplitVectorCalculator<::mediapipe::NormalizedLandmark, false>
+    SplitLandmarkVectorCalculator;
+REGISTER_CALCULATOR(SplitLandmarkVectorCalculator);
+
+typedef SplitVectorCalculator<::mediapipe::NormalizedLandmarkList, false>
+    SplitNormalizedLandmarkListVectorCalculator;
+REGISTER_CALCULATOR(SplitNormalizedLandmarkListVectorCalculator);
+
+typedef SplitVectorCalculator<::mediapipe::NormalizedRect, false>
+    SplitNormalizedRectVectorCalculator;
+REGISTER_CALCULATOR(SplitNormalizedRectVectorCalculator);
+
+typedef SplitVectorCalculator<Matrix, false> SplitMatrixVectorCalculator;
+REGISTER_CALCULATOR(SplitMatrixVectorCalculator);
+
+#if !defined(MEDIAPIPE_DISABLE_GL_COMPUTE)
+typedef SplitVectorCalculator<::tflite::gpu::gl::GlBuffer, true>
+    MovableSplitGlBufferVectorCalculator;
+REGISTER_CALCULATOR(MovableSplitGlBufferVectorCalculator);
+#endif
+
+typedef SplitVectorCalculator<::mediapipe::Detection, false>
+    SplitDetectionVectorCalculator;
+REGISTER_CALCULATOR(SplitDetectionVectorCalculator);
+
 }  // namespace mediapipe
@@ -15,12 +15,14 @@
 #ifndef MEDIAPIPE_CALCULATORS_CORE_SPLIT_VECTOR_CALCULATOR_H_
 #define MEDIAPIPE_CALCULATORS_CORE_SPLIT_VECTOR_CALCULATOR_H_

+#include <type_traits>
 #include <vector>

 #include "mediapipe/calculators/core/split_vector_calculator.pb.h"
 #include "mediapipe/framework/calculator_framework.h"
 #include "mediapipe/framework/port/canonical_errors.h"
 #include "mediapipe/framework/port/ret_check.h"
+#include "mediapipe/framework/port/status.h"
 #include "mediapipe/util/resource_util.h"
 #include "tensorflow/lite/error_reporter.h"
 #include "tensorflow/lite/interpreter.h"
@@ -29,15 +31,31 @@

 namespace mediapipe {

+template <typename T>
+using IsCopyable = std::enable_if_t<std::is_copy_constructible<T>::value, bool>;
+
+template <typename T>
+using IsNotCopyable =
+    std::enable_if_t<!std::is_copy_constructible<T>::value, bool>;
+
+template <typename T>
+using IsMovable = std::enable_if_t<std::is_move_constructible<T>::value, bool>;
+
+template <typename T>
+using IsNotMovable =
+    std::enable_if_t<!std::is_move_constructible<T>::value, bool>;
+
 // Splits an input packet with std::vector<T> into multiple std::vector<T>
 // output packets using the [begin, end) ranges specified in
 // SplitVectorCalculatorOptions. If the option "element_only" is set to true,
 // all ranges should be of size 1 and all outputs will be elements of type T. If
 // "element_only" is false, ranges can be non-zero in size and all outputs will
-// be of type std::vector<T>.
+// be of type std::vector<T>. If the option "combine_outputs" is set to true,
+// only one output stream can be specified and all ranges of elements will be
+// combined into one vector.
 // To use this class for a particular type T, register a calculator using
 // SplitVectorCalculator<T>.
-template <typename T>
+template <typename T, bool move_elements>
 class SplitVectorCalculator : public CalculatorBase {
 public:
  static ::mediapipe::Status GetContract(CalculatorContract* cc) {
@@ -49,28 +67,40 @@ class SplitVectorCalculator : public CalculatorBase {
    const auto& options =
        cc->Options<::mediapipe::SplitVectorCalculatorOptions>();

-    if (cc->Outputs().NumEntries() != options.ranges_size()) {
-      return ::mediapipe::InvalidArgumentError(
-          "The number of output streams should match the number of ranges "
-          "specified in the CalculatorOptions.");
+    if (!std::is_copy_constructible<T>::value || move_elements) {
+      // Ranges of elements shouldn't overlap when the vector contains
+      // non-copyable elements.
+      RET_CHECK_OK(checkRangesDontOverlap(options));
    }

-    // Set the output types for each output stream.
-    for (int i = 0; i < cc->Outputs().NumEntries(); ++i) {
-      if (options.ranges(i).begin() < 0 || options.ranges(i).end() < 0 ||
-          options.ranges(i).begin() >= options.ranges(i).end()) {
+    if (options.combine_outputs()) {
+      RET_CHECK_EQ(cc->Outputs().NumEntries(), 1);
+      cc->Outputs().Index(0).Set<std::vector<T>>();
+      RET_CHECK_OK(checkRangesDontOverlap(options));
+    } else {
+      if (cc->Outputs().NumEntries() != options.ranges_size()) {
        return ::mediapipe::InvalidArgumentError(
-            "Indices should be non-negative and begin index should be less "
-            "than the end index.");
+            "The number of output streams should match the number of ranges "
+            "specified in the CalculatorOptions.");
      }
-      if (options.element_only()) {
-        if (options.ranges(i).end() - options.ranges(i).begin() != 1) {
+
+      // Set the output types for each output stream.
+      for (int i = 0; i < cc->Outputs().NumEntries(); ++i) {
+        if (options.ranges(i).begin() < 0 || options.ranges(i).end() < 0 ||
+            options.ranges(i).begin() >= options.ranges(i).end()) {
          return ::mediapipe::InvalidArgumentError(
-              "Since element_only is true, all ranges should be of size 1.");
+              "Indices should be non-negative and begin index should be less "
+              "than the end index.");
+        }
+        if (options.element_only()) {
+          if (options.ranges(i).end() - options.ranges(i).begin() != 1) {
+            return ::mediapipe::InvalidArgumentError(
+                "Since element_only is true, all ranges should be of size 1.");
+          }
+          cc->Outputs().Index(i).Set<T>();
+        } else {
+          cc->Outputs().Index(i).Set<std::vector<T>>();
        }
-        cc->Outputs().Index(i).Set<T>();
-      } else {
-        cc->Outputs().Index(i).Set<std::vector<T>>();
      }
    }

@@ -83,41 +113,140 @@ class SplitVectorCalculator : public CalculatorBase {
    const auto& options =
        cc->Options<::mediapipe::SplitVectorCalculatorOptions>();

+    element_only_ = options.element_only();
+    combine_outputs_ = options.combine_outputs();
+
    for (const auto& range : options.ranges()) {
      ranges_.push_back({range.begin(), range.end()});
      max_range_end_ = std::max(max_range_end_, range.end());
+      total_elements_ += range.end() - range.begin();
    }

-    element_only_ = options.element_only();
-
    return ::mediapipe::OkStatus();
  }

  ::mediapipe::Status Process(CalculatorContext* cc) override {
-    const auto& input = cc->Inputs().Index(0).Get<std::vector<T>>();
-    RET_CHECK_GE(input.size(), max_range_end_);
+    if (cc->Inputs().Index(0).IsEmpty()) return ::mediapipe::OkStatus();

-    if (element_only_) {
-      for (int i = 0; i < ranges_.size(); ++i) {
-        cc->Outputs().Index(i).AddPacket(
-            MakePacket<T>(input[ranges_[i].first]).At(cc->InputTimestamp()));
-      }
+    if (move_elements) {
+      return ProcessMovableElements<T>(cc);
    } else {
+      return ProcessCopyableElements<T>(cc);
+    }
+  }
+
+  template <typename U, IsCopyable<U> = true>
+  ::mediapipe::Status ProcessCopyableElements(CalculatorContext* cc) {
+    // static_assert(std::is_copy_constructible<U>::value,
+    //              "Cannot copy non-copyable elements");
+    const auto& input = cc->Inputs().Index(0).Get<std::vector<U>>();
+    RET_CHECK_GE(input.size(), max_range_end_);
+    if (combine_outputs_) {
+      auto output = absl::make_unique<std::vector<U>>();
+      output->reserve(total_elements_);
      for (int i = 0; i < ranges_.size(); ++i) {
-        auto output = absl::make_unique<std::vector<T>>(
+        auto elements = absl::make_unique<std::vector<U>>(
            input.begin() + ranges_[i].first,
            input.begin() + ranges_[i].second);
-        cc->Outputs().Index(i).Add(output.release(), cc->InputTimestamp());
+        output->insert(output->end(), elements->begin(), elements->end());
+      }
+      cc->Outputs().Index(0).Add(output.release(), cc->InputTimestamp());
+    } else {
+      if (element_only_) {
+        for (int i = 0; i < ranges_.size(); ++i) {
+          cc->Outputs().Index(i).AddPacket(
+              MakePacket<U>(input[ranges_[i].first]).At(cc->InputTimestamp()));
+        }
+      } else {
+        for (int i = 0; i < ranges_.size(); ++i) {
+          auto output = absl::make_unique<std::vector<T>>(
+              input.begin() + ranges_[i].first,
+              input.begin() + ranges_[i].second);
+          cc->Outputs().Index(i).Add(output.release(), cc->InputTimestamp());
+        }
      }
    }

    return ::mediapipe::OkStatus();
  }

+  template <typename U, IsNotCopyable<U> = true>
+  ::mediapipe::Status ProcessCopyableElements(CalculatorContext* cc) {
+    return ::mediapipe::InternalError("Cannot copy non-copyable elements.");
+  }
+
+  template <typename U, IsMovable<U> = true>
+  ::mediapipe::Status ProcessMovableElements(CalculatorContext* cc) {
+    ::mediapipe::StatusOr<std::unique_ptr<std::vector<U>>> input_status =
+        cc->Inputs().Index(0).Value().Consume<std::vector<U>>();
+    if (!input_status.ok()) return input_status.status();
+    std::unique_ptr<std::vector<U>> input_vector =
+        std::move(input_status).ValueOrDie();
+    RET_CHECK_GE(input_vector->size(), max_range_end_);
+
+    if (combine_outputs_) {
+      auto output = absl::make_unique<std::vector<U>>();
+      output->reserve(total_elements_);
+      for (int i = 0; i < ranges_.size(); ++i) {
+        output->insert(
+            output->end(),
+            std::make_move_iterator(input_vector->begin() + ranges_[i].first),
+            std::make_move_iterator(input_vector->begin() + ranges_[i].second));
+      }
+      cc->Outputs().Index(0).Add(output.release(), cc->InputTimestamp());
+    } else {
+      if (element_only_) {
+        for (int i = 0; i < ranges_.size(); ++i) {
+          cc->Outputs().Index(i).AddPacket(
+              MakePacket<U>(std::move(input_vector->at(ranges_[i].first)))
+                  .At(cc->InputTimestamp()));
+        }
+      } else {
+        for (int i = 0; i < ranges_.size(); ++i) {
+          auto output = absl::make_unique<std::vector<T>>();
+          output->insert(
+              output->end(),
+              std::make_move_iterator(input_vector->begin() + ranges_[i].first),
+              std::make_move_iterator(input_vector->begin() +
+                                      ranges_[i].second));
+          cc->Outputs().Index(i).Add(output.release(), cc->InputTimestamp());
+        }
+      }
+    }
+
+    return ::mediapipe::OkStatus();
+  }
+
+  template <typename U, IsNotMovable<U> = true>
+  ::mediapipe::Status ProcessMovableElements(CalculatorContext* cc) {
+    return ::mediapipe::InternalError("Cannot move non-movable elements.");
+  }
+
 private:
+  static ::mediapipe::Status checkRangesDontOverlap(
+      const ::mediapipe::SplitVectorCalculatorOptions& options) {
+    for (int i = 0; i < options.ranges_size() - 1; ++i) {
+      for (int j = i + 1; j < options.ranges_size(); ++j) {
+        const auto& range_0 = options.ranges(i);
+        const auto& range_1 = options.ranges(j);
+        if ((range_0.begin() >= range_1.begin() &&
+             range_0.begin() < range_1.end()) ||
+            (range_1.begin() >= range_0.begin() &&
+             range_1.begin() < range_0.end())) {
+          return ::mediapipe::InvalidArgumentError(
+              "Ranges must be non-overlapping when using combine_outputs "
+              "option.");
+        }
+      }
+    }
+    return ::mediapipe::OkStatus();
+  }
+
  std::vector<std::pair<int32, int32>> ranges_;
  int32 max_range_end_ = -1;
+  int32 total_elements_ = 0;
  bool element_only_ = false;
+  bool combine_outputs_ = false;
 };

 }  // namespace mediapipe
@@ -37,4 +37,7 @@ message SplitVectorCalculatorOptions {
  // just element of type T. By default, if a range specifies only one element,
  // it is outputted as an std::vector<T>.
  optional bool element_only = 2 [default = false];
+
+  // Combines output elements to one vector.
+  optional bool combine_outputs = 3 [default = false];
 }
@@ -105,6 +105,34 @@ class SplitTfLiteTensorVectorCalculatorTest : public ::testing::Test {
    }
  }

+  void ValidateCombinedVectorOutput(std::vector<Packet>& output_packets,
+                                    int expected_elements,
+                                    std::vector<int>& input_begin_indices,
+                                    std::vector<int>& input_end_indices) {
+    ASSERT_EQ(1, output_packets.size());
+    ASSERT_EQ(input_begin_indices.size(), input_end_indices.size());
+    const std::vector<TfLiteTensor>& output_vec =
+        output_packets[0].Get<std::vector<TfLiteTensor>>();
+    ASSERT_EQ(expected_elements, output_vec.size());
+    const int num_ranges = input_begin_indices.size();
+
+    int element_id = 0;
+    for (int range_id = 0; range_id < num_ranges; ++range_id) {
+      for (int i = input_begin_indices[range_id];
+           i < input_end_indices[range_id]; ++i) {
+        const int expected_value = i;
+        const TfLiteTensor* result = &output_vec[element_id];
+        float* result_buffer = result->data.f;
+        ASSERT_NE(result_buffer, nullptr);
+        ASSERT_EQ(result_buffer, input_buffers_[i]);
+        for (int j = 0; j < width * height * channels; ++j) {
+          ASSERT_EQ(expected_value, result_buffer[j]);
+        }
+        element_id++;
+      }
+    }
+  }
+
  void ValidateElementOutput(std::vector<Packet>& output_packets,
                             int input_begin_index) {
    ASSERT_EQ(1, output_packets.size());
@@ -161,12 +189,12 @@ TEST_F(SplitTfLiteTensorVectorCalculatorTest, SmokeTest) {

  // Run the graph.
  CalculatorGraph graph;
-  MEDIAPIPE_ASSERT_OK(graph.Initialize(graph_config));
-  MEDIAPIPE_ASSERT_OK(graph.StartRun({}));
-  MEDIAPIPE_ASSERT_OK(graph.AddPacketToInputStream(
+  MP_ASSERT_OK(graph.Initialize(graph_config));
+  MP_ASSERT_OK(graph.StartRun({}));
+  MP_ASSERT_OK(graph.AddPacketToInputStream(
      "tensor_in", Adopt(input_vec_.release()).At(Timestamp(0))));
  // Wait until the calculator finishes processing.
-  MEDIAPIPE_ASSERT_OK(graph.WaitUntilIdle());
+  MP_ASSERT_OK(graph.WaitUntilIdle());

  ValidateVectorOutput(range_0_packets, /*expected_elements=*/1,
                       /*input_begin_index=*/0);
@@ -176,8 +204,8 @@ TEST_F(SplitTfLiteTensorVectorCalculatorTest, SmokeTest) {
                       /*input_begin_index=*/4);

  // Fully close the graph at the end.
-  MEDIAPIPE_ASSERT_OK(graph.CloseInputStream("tensor_in"));
-  MEDIAPIPE_ASSERT_OK(graph.WaitUntilDone());
+  MP_ASSERT_OK(graph.CloseInputStream("tensor_in"));
+  MP_ASSERT_OK(graph.WaitUntilDone());
 }

 TEST_F(SplitTfLiteTensorVectorCalculatorTest, InvalidRangeTest) {
@@ -234,6 +262,65 @@ TEST_F(SplitTfLiteTensorVectorCalculatorTest, InvalidOutputStreamCountTest) {
  ASSERT_FALSE(graph.Initialize(graph_config).ok());
 }

+TEST_F(SplitTfLiteTensorVectorCalculatorTest,
+       InvalidCombineOutputsMultipleOutputsTest) {
+  ASSERT_NE(interpreter_, nullptr);
+
+  // Prepare a graph to use the SplitTfLiteTensorVectorCalculator.
+  CalculatorGraphConfig graph_config =
+      ::mediapipe::ParseTextProtoOrDie<CalculatorGraphConfig>(
+          R"(
+            input_stream: "tensor_in"
+            node {
+              calculator: "SplitTfLiteTensorVectorCalculator"
+              input_stream: "tensor_in"
+              output_stream: "range_0"
+              output_stream: "range_1"
+              options {
+                [mediapipe.SplitVectorCalculatorOptions.ext] {
+                  ranges: { begin: 0 end: 1 }
+                  ranges: { begin: 2 end: 3 }
+                  combine_outputs: true
+                }
+              }
+            }
+          )");
+
+  // Run the graph.
+  CalculatorGraph graph;
+  // The graph should fail running because the number of output streams does not
+  // match the number of range elements in the options.
+  ASSERT_FALSE(graph.Initialize(graph_config).ok());
+}
+
+TEST_F(SplitTfLiteTensorVectorCalculatorTest, InvalidOverlappingRangesTest) {
+  ASSERT_NE(interpreter_, nullptr);
+
+  // Prepare a graph to use the SplitTfLiteTensorVectorCalculator.
+  CalculatorGraphConfig graph_config =
+      ::mediapipe::ParseTextProtoOrDie<CalculatorGraphConfig>(
+          R"(
+            input_stream: "tensor_in"
+            node {
+              calculator: "SplitTfLiteTensorVectorCalculator"
+              input_stream: "tensor_in"
+              output_stream: "range_0"
+              options {
+                [mediapipe.SplitVectorCalculatorOptions.ext] {
+                  ranges: { begin: 0 end: 3 }
+                  ranges: { begin: 1 end: 4 }
+                  combine_outputs: true
+                }
+              }
+            }
+          )");
+
+  // Run the graph.
+  CalculatorGraph graph;
+  // The graph should fail running because there are overlapping ranges.
+  ASSERT_FALSE(graph.Initialize(graph_config).ok());
+}
+
 TEST_F(SplitTfLiteTensorVectorCalculatorTest, SmokeTestElementOnly) {
  ASSERT_NE(interpreter_, nullptr);

@@ -270,12 +357,12 @@ TEST_F(SplitTfLiteTensorVectorCalculatorTest, SmokeTestElementOnly) {

  // Run the graph.
  CalculatorGraph graph;
-  MEDIAPIPE_ASSERT_OK(graph.Initialize(graph_config));
-  MEDIAPIPE_ASSERT_OK(graph.StartRun({}));
-  MEDIAPIPE_ASSERT_OK(graph.AddPacketToInputStream(
+  MP_ASSERT_OK(graph.Initialize(graph_config));
+  MP_ASSERT_OK(graph.StartRun({}));
+  MP_ASSERT_OK(graph.AddPacketToInputStream(
      "tensor_in", Adopt(input_vec_.release()).At(Timestamp(0))));
  // Wait until the calculator finishes processing.
-  MEDIAPIPE_ASSERT_OK(graph.WaitUntilIdle());
+  MP_ASSERT_OK(graph.WaitUntilIdle());

  ValidateElementOutput(range_0_packets,
                        /*input_begin_index=*/0);
@@ -285,8 +372,55 @@ TEST_F(SplitTfLiteTensorVectorCalculatorTest, SmokeTestElementOnly) {
                        /*input_begin_index=*/4);

  // Fully close the graph at the end.
-  MEDIAPIPE_ASSERT_OK(graph.CloseInputStream("tensor_in"));
-  MEDIAPIPE_ASSERT_OK(graph.WaitUntilDone());
+  MP_ASSERT_OK(graph.CloseInputStream("tensor_in"));
+  MP_ASSERT_OK(graph.WaitUntilDone());
+}
+
+TEST_F(SplitTfLiteTensorVectorCalculatorTest, SmokeTestCombiningOutputs) {
+  ASSERT_NE(interpreter_, nullptr);
+
+  PrepareTfLiteTensorVector(/*vector_size=*/5);
+  ASSERT_NE(input_vec_, nullptr);
+
+  // Prepare a graph to use the SplitTfLiteTensorVectorCalculator.
+  CalculatorGraphConfig graph_config =
+      ::mediapipe::ParseTextProtoOrDie<CalculatorGraphConfig>(
+          R"(
+            input_stream: "tensor_in"
+            node {
+              calculator: "SplitTfLiteTensorVectorCalculator"
+              input_stream: "tensor_in"
+              output_stream: "range_0"
+              options {
+                [mediapipe.SplitVectorCalculatorOptions.ext] {
+                  ranges: { begin: 0 end: 1 }
+                  ranges: { begin: 2 end: 3 }
+                  ranges: { begin: 4 end: 5 }
+                  combine_outputs: true
+                }
+              }
+            }
+          )");
+  std::vector<Packet> range_0_packets;
+  tool::AddVectorSink("range_0", &graph_config, &range_0_packets);
+
+  // Run the graph.
+  CalculatorGraph graph;
+  MP_ASSERT_OK(graph.Initialize(graph_config));
+  MP_ASSERT_OK(graph.StartRun({}));
+  MP_ASSERT_OK(graph.AddPacketToInputStream(
+      "tensor_in", Adopt(input_vec_.release()).At(Timestamp(0))));
+  // Wait until the calculator finishes processing.
+  MP_ASSERT_OK(graph.WaitUntilIdle());
+
+  std::vector<int> input_begin_indices = {0, 2, 4};
+  std::vector<int> input_end_indices = {1, 3, 5};
+  ValidateCombinedVectorOutput(range_0_packets, /*expected_elements=*/3,
+                               input_begin_indices, input_end_indices);
+
+  // Fully close the graph at the end.
+  MP_ASSERT_OK(graph.CloseInputStream("tensor_in"));
+  MP_ASSERT_OK(graph.WaitUntilDone());
 }

 TEST_F(SplitTfLiteTensorVectorCalculatorTest,
@@ -318,4 +452,243 @@ TEST_F(SplitTfLiteTensorVectorCalculatorTest,
  ASSERT_FALSE(graph.Initialize(graph_config).ok());
 }

+typedef SplitVectorCalculator<std::unique_ptr<int>, true>
+    MovableSplitUniqueIntPtrCalculator;
+REGISTER_CALCULATOR(MovableSplitUniqueIntPtrCalculator);
+
+class MovableSplitUniqueIntPtrCalculatorTest : public ::testing::Test {
+ protected:
+  void ValidateVectorOutput(std::vector<Packet>& output_packets,
+                            int expected_elements, int input_begin_index) {
+    ASSERT_EQ(1, output_packets.size());
+    const std::vector<std::unique_ptr<int>>& output_vec =
+        output_packets[0].Get<std::vector<std::unique_ptr<int>>>();
+    ASSERT_EQ(expected_elements, output_vec.size());
+
+    for (int i = 0; i < expected_elements; ++i) {
+      const int expected_value = input_begin_index + i;
+      const std::unique_ptr<int>& result = output_vec[i];
+      ASSERT_NE(result, nullptr);
+      ASSERT_EQ(expected_value, *result);
+    }
+  }
+
+  void ValidateElementOutput(std::vector<Packet>& output_packets,
+                             int expected_value) {
+    ASSERT_EQ(1, output_packets.size());
+    const std::unique_ptr<int>& result =
+        output_packets[0].Get<std::unique_ptr<int>>();
+    ASSERT_NE(result, nullptr);
+    ASSERT_EQ(expected_value, *result);
+  }
+
+  void ValidateCombinedVectorOutput(std::vector<Packet>& output_packets,
+                                    int expected_elements,
+                                    std::vector<int>& input_begin_indices,
+                                    std::vector<int>& input_end_indices) {
+    ASSERT_EQ(1, output_packets.size());
+    ASSERT_EQ(input_begin_indices.size(), input_end_indices.size());
+    const std::vector<std::unique_ptr<int>>& output_vector =
+        output_packets[0].Get<std::vector<std::unique_ptr<int>>>();
+    ASSERT_EQ(expected_elements, output_vector.size());
+    const int num_ranges = input_begin_indices.size();
+
+    int element_id = 0;
+    for (int range_id = 0; range_id < num_ranges; ++range_id) {
+      for (int i = input_begin_indices[range_id];
+           i < input_end_indices[range_id]; ++i) {
+        const int expected_value = i;
+        const std::unique_ptr<int>& result = output_vector[element_id];
+        ASSERT_NE(result, nullptr);
+        ASSERT_EQ(expected_value, *result);
+        ++element_id;
+      }
+    }
+  }
+};
+
+TEST_F(MovableSplitUniqueIntPtrCalculatorTest, InvalidOverlappingRangesTest) {
+  // Prepare a graph to use the TestMovableSplitUniqueIntPtrVectorCalculator.
+  CalculatorGraphConfig graph_config =
+      ::mediapipe::ParseTextProtoOrDie<CalculatorGraphConfig>(
+          R"(
+            input_stream: "input_vector"
+            node {
+              calculator: "MovableSplitUniqueIntPtrCalculator"
+              input_stream: "input_vector"
+              output_stream: "range_0"
+              options {
+                [mediapipe.SplitVectorCalculatorOptions.ext] {
+                  ranges: { begin: 0 end: 3 }
+                  ranges: { begin: 1 end: 4 }
+                }
+              }
+            }
+          )");
+
+  // Run the graph.
+  CalculatorGraph graph;
+  // The graph should fail running because there are overlapping ranges.
+  ASSERT_FALSE(graph.Initialize(graph_config).ok());
+}
+
+TEST_F(MovableSplitUniqueIntPtrCalculatorTest, SmokeTest) {
+  // Prepare a graph to use the TestMovableSplitUniqueIntPtrVectorCalculator.
+  CalculatorGraphConfig graph_config =
+      ::mediapipe::ParseTextProtoOrDie<CalculatorGraphConfig>(
+          R"(
+            input_stream: "input_vector"
+            node {
+              calculator: "MovableSplitUniqueIntPtrCalculator"
+              input_stream: "input_vector"
+              output_stream: "range_0"
+              output_stream: "range_1"
+              output_stream: "range_2"
+              options {
+                [mediapipe.SplitVectorCalculatorOptions.ext] {
+                  ranges: { begin: 0 end: 1 }
+                  ranges: { begin: 1 end: 4 }
+                  ranges: { begin: 4 end: 5 }
+                }
+              }
+            }
+          )");
+
+  std::vector<Packet> range_0_packets;
+  tool::AddVectorSink("range_0", &graph_config, &range_0_packets);
+  std::vector<Packet> range_1_packets;
+  tool::AddVectorSink("range_1", &graph_config, &range_1_packets);
+  std::vector<Packet> range_2_packets;
+  tool::AddVectorSink("range_2", &graph_config, &range_2_packets);
+
+  // Run the graph.
+  CalculatorGraph graph;
+  MP_ASSERT_OK(graph.Initialize(graph_config));
+  MP_ASSERT_OK(graph.StartRun({}));
+
+  // input_vector : {0, 1, 2, 3, 4, 5}
+  std::unique_ptr<std::vector<std::unique_ptr<int>>> input_vector =
+      absl::make_unique<std::vector<std::unique_ptr<int>>>(6);
+  for (int i = 0; i < 6; ++i) {
+    input_vector->at(i) = absl::make_unique<int>(i);
+  }
+
+  MP_ASSERT_OK(graph.AddPacketToInputStream(
+      "input_vector", Adopt(input_vector.release()).At(Timestamp(1))));
+
+  MP_ASSERT_OK(graph.WaitUntilIdle());
+  MP_ASSERT_OK(graph.CloseAllPacketSources());
+  MP_ASSERT_OK(graph.WaitUntilDone());
+
+  ValidateVectorOutput(range_0_packets, /*expected_elements=*/1,
+                       /*input_begin_index=*/0);
+  ValidateVectorOutput(range_1_packets, /*expected_elements=*/3,
+                       /*input_begin_index=*/1);
+  ValidateVectorOutput(range_2_packets, /*expected_elements=*/1,
+                       /*input_begin_index=*/4);
+}
+
+TEST_F(MovableSplitUniqueIntPtrCalculatorTest, SmokeTestElementOnly) {
+  // Prepare a graph to use the TestMovableSplitUniqueIntPtrVectorCalculator.
+  CalculatorGraphConfig graph_config =
+      ::mediapipe::ParseTextProtoOrDie<CalculatorGraphConfig>(
+          R"(
+            input_stream: "input_vector"
+            node {
+              calculator: "MovableSplitUniqueIntPtrCalculator"
+              input_stream: "input_vector"
+              output_stream: "range_0"
+              output_stream: "range_1"
+              output_stream: "range_2"
+              options {
+                [mediapipe.SplitVectorCalculatorOptions.ext] {
+                  ranges: { begin: 0 end: 1 }
+                  ranges: { begin: 2 end: 3 }
+                  ranges: { begin: 4 end: 5 }
+                  element_only: true
+                }
+              }
+            }
+          )");
+
+  std::vector<Packet> range_0_packets;
+  tool::AddVectorSink("range_0", &graph_config, &range_0_packets);
+  std::vector<Packet> range_1_packets;
+  tool::AddVectorSink("range_1", &graph_config, &range_1_packets);
+  std::vector<Packet> range_2_packets;
+  tool::AddVectorSink("range_2", &graph_config, &range_2_packets);
+
+  // Run the graph.
+  CalculatorGraph graph;
+  MP_ASSERT_OK(graph.Initialize(graph_config));
+  MP_ASSERT_OK(graph.StartRun({}));
+
+  // input_vector : {0, 1, 2, 3, 4, 5}
+  std::unique_ptr<std::vector<std::unique_ptr<int>>> input_vector =
+      absl::make_unique<std::vector<std::unique_ptr<int>>>(6);
+  for (int i = 0; i < 6; ++i) {
+    input_vector->at(i) = absl::make_unique<int>(i);
+  }
+
+  MP_ASSERT_OK(graph.AddPacketToInputStream(
+      "input_vector", Adopt(input_vector.release()).At(Timestamp(1))));
+
+  MP_ASSERT_OK(graph.WaitUntilIdle());
+  MP_ASSERT_OK(graph.CloseAllPacketSources());
+  MP_ASSERT_OK(graph.WaitUntilDone());
+
+  ValidateElementOutput(range_0_packets, /*expected_value=*/0);
+  ValidateElementOutput(range_1_packets, /*expected_value=*/2);
+  ValidateElementOutput(range_2_packets, /*expected_value=*/4);
+}
+
+TEST_F(MovableSplitUniqueIntPtrCalculatorTest, SmokeTestCombiningOutputs) {
+  // Prepare a graph to use the TestMovableSplitUniqueIntPtrVectorCalculator.
+  CalculatorGraphConfig graph_config =
+      ::mediapipe::ParseTextProtoOrDie<CalculatorGraphConfig>(
+          R"(
+            input_stream: "input_vector"
+            node {
+              calculator: "MovableSplitUniqueIntPtrCalculator"
+              input_stream: "input_vector"
+              output_stream: "range_0"
+              options {
+                [mediapipe.SplitVectorCalculatorOptions.ext] {
+                  ranges: { begin: 0 end: 1 }
+                  ranges: { begin: 2 end: 3 }
+                  ranges: { begin: 4 end: 5 }
+                  combine_outputs: true
+                }
+              }
+            }
+          )");
+
+  std::vector<Packet> range_0_packets;
+  tool::AddVectorSink("range_0", &graph_config, &range_0_packets);
+
+  // Run the graph.
+  CalculatorGraph graph;
+  MP_ASSERT_OK(graph.Initialize(graph_config));
+  MP_ASSERT_OK(graph.StartRun({}));
+
+  // input_vector : {0, 1, 2, 3, 4, 5}
+  std::unique_ptr<std::vector<std::unique_ptr<int>>> input_vector =
+      absl::make_unique<std::vector<std::unique_ptr<int>>>(6);
+  for (int i = 0; i < 6; ++i) {
+    input_vector->at(i) = absl::make_unique<int>(i);
+  }
+
+  MP_ASSERT_OK(graph.AddPacketToInputStream(
+      "input_vector", Adopt(input_vector.release()).At(Timestamp(1))));
+
+  MP_ASSERT_OK(graph.WaitUntilIdle());
+  MP_ASSERT_OK(graph.CloseAllPacketSources());
+  MP_ASSERT_OK(graph.WaitUntilDone());
+
+  std::vector<int> input_begin_indices = {0, 2, 4};
+  std::vector<int> input_end_indices = {1, 3, 5};
+  ValidateCombinedVectorOutput(range_0_packets, /*expected_elements=*/3,
+                               input_begin_indices, input_end_indices);
+}
+
 }  // namespace mediapipe
@@ -0,0 +1,48 @@
+// Copyright 2019 The MediaPipe Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "mediapipe/framework/calculator_framework.h"
+#include "mediapipe/framework/port/status.h"
+#include "mediapipe/framework/timestamp.h"
+
+namespace mediapipe {
+
+// A calculator that takes a packet of an input stream and converts it to an
+// output side packet. This calculator only works under the assumption that the
+// input stream only has a single packet passing through.
+//
+// Example config:
+// node {
+//   calculator: "StreamToSidePacketCalculator"
+//   input_stream: "stream"
+//   output_side_packet: "side_packet"
+// }
+class StreamToSidePacketCalculator : public mediapipe::CalculatorBase {
+ public:
+  static mediapipe::Status GetContract(mediapipe::CalculatorContract* cc) {
+    cc->Inputs().Index(0).SetAny();
+    cc->OutputSidePackets().Index(0).SetAny();
+    return mediapipe::OkStatus();
+  }
+
+  mediapipe::Status Process(mediapipe::CalculatorContext* cc) override {
+    mediapipe::Packet& packet = cc->Inputs().Index(0).Value();
+    cc->OutputSidePackets().Index(0).Set(
+        packet.At(mediapipe::Timestamp::Unset()));
+    return mediapipe::OkStatus();
+  }
+};
+REGISTER_CALCULATOR(StreamToSidePacketCalculator);
+
+}  // namespace mediapipe
@@ -0,0 +1,67 @@
+// Copyright 2019 The MediaPipe Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include <memory>
+#include <string>
+
+#include "absl/memory/memory.h"
+#include "mediapipe/framework/calculator_runner.h"
+#include "mediapipe/framework/packet.h"
+#include "mediapipe/framework/port/gmock.h"
+#include "mediapipe/framework/port/gtest.h"
+#include "mediapipe/framework/port/status.h"
+#include "mediapipe/framework/port/status_matchers.h"
+#include "mediapipe/framework/timestamp.h"
+
+namespace mediapipe {
+
+using ::testing::Test;
+
+class StreamToSidePacketCalculatorTest : public Test {
+ protected:
+  StreamToSidePacketCalculatorTest() {
+    const char kConfig[] = R"(
+      calculator: "StreamToSidePacketCalculator"
+      input_stream: "stream"
+      output_side_packet: "side_packet"
+    )";
+    runner_ = absl::make_unique<CalculatorRunner>(kConfig);
+  }
+
+  std::unique_ptr<CalculatorRunner> runner_;
+};
+
+TEST_F(StreamToSidePacketCalculatorTest,
+       StreamToSidePacketCalculatorWithEmptyStreamFails) {
+  EXPECT_EQ(runner_->Run().code(), mediapipe::StatusCode::kUnavailable);
+}
+
+TEST_F(StreamToSidePacketCalculatorTest,
+       StreamToSidePacketCalculatorWithSinglePacketCreatesSidePacket) {
+  runner_->MutableInputs()->Index(0).packets.push_back(
+      Adopt(new std::string("test")).At(Timestamp(1)));
+  MP_ASSERT_OK(runner_->Run());
+  EXPECT_EQ(runner_->OutputSidePackets().Index(0).Get<std::string>(), "test");
+}
+
+TEST_F(StreamToSidePacketCalculatorTest,
+       StreamToSidePacketCalculatorWithMultiplePacketsFails) {
+  runner_->MutableInputs()->Index(0).packets.push_back(
+      Adopt(new std::string("test1")).At(Timestamp(1)));
+  runner_->MutableInputs()->Index(0).packets.push_back(
+      Adopt(new std::string("test2")).At(Timestamp(2)));
+  EXPECT_EQ(runner_->Run().code(), mediapipe::StatusCode::kAlreadyExists);
+}
+
+}  // namespace mediapipe
@@ -0,0 +1,79 @@
+// Copyright 2019 The MediaPipe Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include <sys/types.h>
+
+#include <memory>
+#include <string>
+
+#include "absl/strings/numbers.h"
+#include "mediapipe/framework/calculator_framework.h"
+#include "mediapipe/framework/port/integral_types.h"
+#include "mediapipe/framework/port/status.h"
+
+namespace mediapipe {
+
+// Calculator that converts a std::string into an integer type, or fails if the
+// conversion is not possible.
+//
+// Example config:
+// node {
+//   calculator: "StringToIntCalculator"
+//   input_side_packet: "string"
+//   output_side_packet: "index"
+// }
+template <typename IntType>
+class StringToIntCalculatorTemplate : public CalculatorBase {
+ public:
+  static ::mediapipe::Status GetContract(CalculatorContract* cc) {
+    cc->InputSidePackets().Index(0).Set<std::string>();
+    cc->OutputSidePackets().Index(0).Set<IntType>();
+    return ::mediapipe::OkStatus();
+  }
+
+  ::mediapipe::Status Open(CalculatorContext* cc) override {
+    IntType number;
+    if (!absl::SimpleAtoi(cc->InputSidePackets().Index(0).Get<std::string>(),
+                          &number)) {
+      return ::mediapipe::InvalidArgumentError(
+          "The std::string could not be parsed as an integer.");
+    }
+    cc->OutputSidePackets().Index(0).Set(MakePacket<IntType>(number));
+    return ::mediapipe::OkStatus();
+  }
+
+  ::mediapipe::Status Process(CalculatorContext* cc) override {
+    return ::mediapipe::OkStatus();
+  }
+};
+
+using StringToIntCalculator = StringToIntCalculatorTemplate<int>;
+REGISTER_CALCULATOR(StringToIntCalculator);
+
+using StringToUintCalculator = StringToIntCalculatorTemplate<uint>;
+REGISTER_CALCULATOR(StringToUintCalculator);
+
+using StringToInt32Calculator = StringToIntCalculatorTemplate<int32>;
+REGISTER_CALCULATOR(StringToInt32Calculator);
+
+using StringToUint32Calculator = StringToIntCalculatorTemplate<uint32>;
+REGISTER_CALCULATOR(StringToUint32Calculator);
+
+using StringToInt64Calculator = StringToIntCalculatorTemplate<int64>;
+REGISTER_CALCULATOR(StringToInt64Calculator);
+
+using StringToUint64Calculator = StringToIntCalculatorTemplate<uint64>;
+REGISTER_CALCULATOR(StringToUint64Calculator);
+
+}  // namespace mediapipe
@@ -12,15 +12,14 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.

+load("//mediapipe/framework/port:build_config.bzl", "mediapipe_cc_proto_library")
+
 licenses(["notice"])  # Apache 2.0

 package(default_visibility = ["//visibility:private"])

 exports_files(["LICENSE"])

-load("//mediapipe/framework/port:build_config.bzl", "mediapipe_cc_proto_library")
-load("@bazel_skylib//lib:selects.bzl", "selects")
-
 proto_library(
    name = "opencv_image_encoder_calculator_proto",
    srcs = ["opencv_image_encoder_calculator.proto"],
@@ -81,15 +80,25 @@ mediapipe_cc_proto_library(
    name = "opencv_image_encoder_calculator_cc_proto",
    srcs = ["opencv_image_encoder_calculator.proto"],
    cc_deps = ["//mediapipe/framework:calculator_cc_proto"],
-    visibility = ["//mediapipe:__subpackages__"],
+    visibility = [
+        "//visibility:public",
+    ],
    deps = [":opencv_image_encoder_calculator_proto"],
 )

+mediapipe_cc_proto_library(
+    name = "opencv_encoded_image_to_image_frame_calculator_cc_proto",
+    srcs = ["opencv_encoded_image_to_image_frame_calculator.proto"],
+    cc_deps = ["//mediapipe/framework:calculator_cc_proto"],
+    visibility = ["//visibility:public"],
+    deps = [":opencv_encoded_image_to_image_frame_calculator_proto"],
+)
+
 mediapipe_cc_proto_library(
    name = "mask_overlay_calculator_cc_proto",
    srcs = ["mask_overlay_calculator.proto"],
    cc_deps = ["//mediapipe/framework:calculator_cc_proto"],
-    visibility = ["//mediapipe:__subpackages__"],
+    visibility = ["//visibility:public"],
    deps = [":mask_overlay_calculator_proto"],
 )

@@ -100,7 +109,7 @@ mediapipe_cc_proto_library(
        "//mediapipe/framework:calculator_cc_proto",
        "//mediapipe/framework/formats:image_format_cc_proto",
    ],
-    visibility = ["//mediapipe:__subpackages__"],
+    visibility = ["//visibility:public"],
    deps = [":scale_image_calculator_proto"],
 )

@@ -110,7 +119,7 @@ mediapipe_cc_proto_library(
    cc_deps = [
        "//mediapipe/framework:calculator_cc_proto",
    ],
-    visibility = ["//mediapipe:__subpackages__"],
+    visibility = ["//visibility:public"],
    deps = [":set_alpha_calculator_proto"],
 )

@@ -120,17 +129,17 @@ mediapipe_cc_proto_library(
    cc_deps = [
        "//mediapipe/framework:calculator_cc_proto",
    ],
-    visibility = ["//mediapipe:__subpackages__"],
+    visibility = ["//visibility:public"],
    deps = [":image_cropping_calculator_proto"],
 )

 mediapipe_cc_proto_library(
    name = "bilateral_filter_calculator_cc_proto",
    srcs = ["bilateral_filter_calculator.proto"],
-    cc_deps = [
-        "//mediapipe/framework:calculator_cc_proto",
+    cc_deps = ["//mediapipe/framework:calculator_cc_proto"],
+    visibility = [
+        "//visibility:public",
    ],
-    visibility = ["//mediapipe:__subpackages__"],
    deps = [":bilateral_filter_calculator_proto"],
 )

@@ -141,7 +150,7 @@ mediapipe_cc_proto_library(
        "//mediapipe/framework:calculator_cc_proto",
        "//mediapipe/util:color_cc_proto",
    ],
-    visibility = ["//mediapipe:__subpackages__"],
+    visibility = ["//visibility:public"],
    deps = [":recolor_calculator_proto"],
 )

@@ -171,6 +180,7 @@ cc_library(
    srcs = ["opencv_encoded_image_to_image_frame_calculator.cc"],
    visibility = ["//visibility:public"],
    deps = [
+        ":opencv_encoded_image_to_image_frame_calculator_cc_proto",
        "//mediapipe/framework:calculator_framework",
        "//mediapipe/framework/formats:image_frame_opencv",
        "//mediapipe/framework/port:opencv_imgcodecs",
@@ -227,19 +237,13 @@ cc_library(
        "//mediapipe/framework/port:status",
        "//mediapipe/framework/port:vector",
    ] + select({
-        "//mediapipe:android": [
+        "//mediapipe/gpu:disable_gpu": [],
+        "//conditions:default": [
            "//mediapipe/gpu:gl_calculator_helper",
            "//mediapipe/gpu:gl_simple_shaders",
-            "//mediapipe/gpu:gpu_buffer",
+            "//mediapipe/gpu:gl_quad_renderer",
            "//mediapipe/gpu:shader_util",
        ],
-        "//mediapipe:ios": [
-            "//mediapipe/gpu:gl_calculator_helper",
-            "//mediapipe/gpu:gl_simple_shaders",
-            "//mediapipe/gpu:gpu_buffer",
-            "//mediapipe/gpu:shader_util",
-        ],
-        "//conditions:default": [],
    }),
    alwayslink = 1,
 )
@@ -263,13 +267,13 @@ cc_library(
        "//mediapipe/framework/port:status",
        "//mediapipe/framework/port:vector",
    ] + select({
-        "//mediapipe:android": [
+        "//mediapipe/gpu:disable_gpu": [],
+        "//conditions:default": [
            "//mediapipe/gpu:gl_calculator_helper",
            "//mediapipe/gpu:gl_simple_shaders",
-            "//mediapipe/gpu:gpu_buffer",
+            "//mediapipe/gpu:gl_quad_renderer",
            "//mediapipe/gpu:shader_util",
        ],
-        "//conditions:default": [],
    }),
    alwayslink = 1,
 )
@@ -291,7 +295,7 @@ mediapipe_cc_proto_library(
        "//mediapipe/framework:calculator_cc_proto",
        "//mediapipe/gpu:scale_mode_cc_proto",
    ],
-    visibility = ["//mediapipe:__subpackages__"],
+    visibility = ["//visibility:public"],
    deps = [":image_transformation_calculator_proto"],
 )

@@ -322,14 +326,14 @@ cc_library(
        "//mediapipe/framework/port:opencv_imgproc",
        "//mediapipe/framework/port:ret_check",
        "//mediapipe/framework/port:status",
-    ] + selects.with_or({
-        ("//mediapipe:android", "//mediapipe:ios"): [
+    ] + select({
+        "//mediapipe/gpu:disable_gpu": [],
+        "//conditions:default": [
            "//mediapipe/gpu:gl_calculator_helper",
            "//mediapipe/gpu:gl_simple_shaders",
            "//mediapipe/gpu:gl_quad_renderer",
            "//mediapipe/gpu:shader_util",
        ],
-        "//conditions:default": [],
    }),
    alwayslink = 1,
 )
@@ -337,6 +341,7 @@ cc_library(
 cc_library(
    name = "image_cropping_calculator",
    srcs = ["image_cropping_calculator.cc"],
+    hdrs = ["image_cropping_calculator.h"],
    copts = select({
        "//mediapipe:apple": [
            "-x objective-c++",
@@ -350,9 +355,7 @@ cc_library(
        ],
        "//conditions:default": [],
    }),
-    visibility = [
-        "//visibility:public",
-    ],
+    visibility = ["//visibility:public"],
    deps = [
        ":image_cropping_calculator_cc_proto",
        "//mediapipe/framework:calculator_framework",
@@ -363,18 +366,35 @@ cc_library(
        "//mediapipe/framework/port:opencv_imgproc",
        "//mediapipe/framework/port:ret_check",
        "//mediapipe/framework/port:status",
-    ] + selects.with_or({
-        ("//mediapipe:android", "//mediapipe:ios"): [
+    ] + select({
+        "//mediapipe/gpu:disable_gpu": [],
+        "//conditions:default": [
            "//mediapipe/gpu:gl_calculator_helper",
            "//mediapipe/gpu:gl_simple_shaders",
            "//mediapipe/gpu:gl_quad_renderer",
+            "//mediapipe/gpu:gpu_buffer",
            "//mediapipe/gpu:shader_util",
        ],
-        "//conditions:default": [],
    }),
    alwayslink = 1,
 )

+cc_test(
+    name = "image_cropping_calculator_test",
+    srcs = ["image_cropping_calculator_test.cc"],
+    deps = [
+        ":image_cropping_calculator",
+        ":image_cropping_calculator_cc_proto",
+        "//mediapipe/framework:calculator_framework",
+        "//mediapipe/framework/formats:rect_cc_proto",
+        "//mediapipe/framework/port:gtest_main",
+        "//mediapipe/framework/port:parse_text_proto",
+        "//mediapipe/framework/port:status",
+        "//mediapipe/framework/tool:tag_map",
+        "//mediapipe/framework/tool:tag_map_helper",
+    ],
+)
+
 cc_library(
    name = "luminance_calculator",
    srcs = ["luminance_calculator.cc"],
@@ -411,23 +431,20 @@ cc_library(
        ":recolor_calculator_cc_proto",
        "//mediapipe/framework:calculator_framework",
        "//mediapipe/framework/formats:image_frame",
+        "//mediapipe/framework/formats:image_frame_opencv",
        "//mediapipe/framework/port:status",
        "//mediapipe/framework/port:ret_check",
        "//mediapipe/util:color_cc_proto",
+        "//mediapipe/framework/port:opencv_core",
+        "//mediapipe/framework/port:opencv_imgproc",
    ] + select({
-        "//mediapipe:android": [
+        "//mediapipe/gpu:disable_gpu": [],
+        "//conditions:default": [
            "//mediapipe/gpu:gl_calculator_helper",
            "//mediapipe/gpu:gl_simple_shaders",
-            "//mediapipe/gpu:gpu_buffer",
+            "//mediapipe/gpu:gl_quad_renderer",
            "//mediapipe/gpu:shader_util",
        ],
-        "//mediapipe:ios": [
-            "//mediapipe/gpu:gl_calculator_helper",
-            "//mediapipe/gpu:gl_simple_shaders",
-            "//mediapipe/gpu:gpu_buffer",
-            "//mediapipe/gpu:shader_util",
-        ],
-        "//conditions:default": [],
    }),
    alwayslink = 1,
 )
@@ -486,11 +503,11 @@ cc_library(
        "//mediapipe/framework/formats:image_frame",
        "//mediapipe/framework/port:ret_check",
        "//mediapipe/framework/port:status",
-    ] + selects.with_or({
-        ("//mediapipe:android", "//mediapipe:ios"): [
+    ] + select({
+        "//mediapipe/gpu:disable_gpu": [],
+        "//conditions:default": [
            "//mediapipe/gpu:gpu_buffer",
        ],
-        "//conditions:default": [],
    }),
    alwayslink = 1,
 )
@@ -549,6 +566,27 @@ proto_library(
    deps = ["//mediapipe/framework:calculator_proto"],
 )

+proto_library(
+    name = "opencv_encoded_image_to_image_frame_calculator_proto",
+    srcs = ["opencv_encoded_image_to_image_frame_calculator.proto"],
+    visibility = ["//visibility:public"],
+    deps = ["//mediapipe/framework:calculator_proto"],
+)
+
+proto_library(
+    name = "feature_detector_calculator_proto",
+    srcs = ["feature_detector_calculator.proto"],
+    deps = ["//mediapipe/framework:calculator_proto"],
+)
+
+mediapipe_cc_proto_library(
+    name = "feature_detector_calculator_cc_proto",
+    srcs = ["feature_detector_calculator.proto"],
+    cc_deps = ["//mediapipe/framework:calculator_cc_proto"],
+    visibility = ["//visibility:public"],
+    deps = [":feature_detector_calculator_proto"],
+)
+
 cc_library(
    name = "mask_overlay_calculator",
    srcs = ["mask_overlay_calculator.cc"],
@@ -564,3 +602,30 @@ cc_library(
    ],
    alwayslink = 1,
 )
+
+cc_library(
+    name = "feature_detector_calculator",
+    srcs = ["feature_detector_calculator.cc"],
+    visibility = ["//mediapipe:__subpackages__"],
+    deps = [
+        ":feature_detector_calculator_cc_proto",
+        "//mediapipe/framework:calculator_framework",
+        "//mediapipe/framework/formats:image_frame",
+        "//mediapipe/framework/formats:image_frame_opencv",
+        "//mediapipe/framework/formats:landmark_cc_proto",
+        "//mediapipe/framework/formats:video_stream_header",
+        "//mediapipe/framework/port:integral_types",
+        "//mediapipe/framework/port:logging",
+        "//mediapipe/framework/port:opencv_core",
+        "//mediapipe/framework/port:opencv_features2d",
+        "//mediapipe/framework/port:opencv_imgproc",
+        "//mediapipe/framework/port:ret_check",
+        "//mediapipe/framework/port:status",
+        "//mediapipe/framework/port:threadpool",
+        "//mediapipe/framework/tool:options_util",
+        "@com_google_absl//absl/memory",
+        "@com_google_absl//absl/synchronization",
+        "@org_tensorflow//tensorflow/lite:framework",
+    ],
+    alwayslink = 1,
+)
@@ -27,11 +27,11 @@
 #include "mediapipe/framework/port/status.h"
 #include "mediapipe/framework/port/vector.h"

-#if defined(__ANDROID__) || defined(__EMSCRIPTEN__)
+#if !defined(MEDIAPIPE_DISABLE_GPU)
 #include "mediapipe/gpu/gl_calculator_helper.h"
 #include "mediapipe/gpu/gl_simple_shaders.h"
 #include "mediapipe/gpu/shader_util.h"
-#endif  // __ANDROID__ || __EMSCRIPTEN__
+#endif  //  !MEDIAPIPE_DISABLE_GPU

 namespace mediapipe {

@@ -101,11 +101,11 @@ class BilateralFilterCalculator : public CalculatorBase {

  bool use_gpu_ = false;
  bool gpu_initialized_ = false;
-#if defined(__ANDROID__) || defined(__EMSCRIPTEN__)
+#if !defined(MEDIAPIPE_DISABLE_GPU)
  mediapipe::GlCalculatorHelper gpu_helper_;
  GLuint program_ = 0;
  GLuint program_joint_ = 0;
-#endif  // __ANDROID__ || __EMSCRIPTEN__
+#endif  //  !MEDIAPIPE_DISABLE_GPU
 };
 REGISTER_CALCULATOR(BilateralFilterCalculator);

@@ -122,39 +122,46 @@ REGISTER_CALCULATOR(BilateralFilterCalculator);
    return ::mediapipe::InternalError("GPU output must have GPU input.");
  }

+  bool use_gpu = false;
+
  // Input image to filter.
-#if defined(__ANDROID__) || defined(__EMSCRIPTEN__)
+#if !defined(MEDIAPIPE_DISABLE_GPU)
  if (cc->Inputs().HasTag(kInputFrameTagGpu)) {
    cc->Inputs().Tag(kInputFrameTagGpu).Set<mediapipe::GpuBuffer>();
+    use_gpu |= true;
  }
-#endif  // __ANDROID__ || __EMSCRIPTEN__
+#endif  //  !MEDIAPIPE_DISABLE_GPU
  if (cc->Inputs().HasTag(kInputFrameTag)) {
    cc->Inputs().Tag(kInputFrameTag).Set<ImageFrame>();
  }

  // Input guide image mask (optional)
+#if !defined(MEDIAPIPE_DISABLE_GPU)
  if (cc->Inputs().HasTag(kInputGuideTagGpu)) {
-#if defined(__ANDROID__) || defined(__EMSCRIPTEN__)
    cc->Inputs().Tag(kInputGuideTagGpu).Set<mediapipe::GpuBuffer>();
-#endif  // __ANDROID__ || __EMSCRIPTEN__
+    use_gpu |= true;
  }
+#endif  //  !MEDIAPIPE_DISABLE_GPU
  if (cc->Inputs().HasTag(kInputGuideTag)) {
    cc->Inputs().Tag(kInputGuideTag).Set<ImageFrame>();
  }

  // Output image.
-#if defined(__ANDROID__) || defined(__EMSCRIPTEN__)
+#if !defined(MEDIAPIPE_DISABLE_GPU)
  if (cc->Outputs().HasTag(kOutputFrameTagGpu)) {
    cc->Outputs().Tag(kOutputFrameTagGpu).Set<mediapipe::GpuBuffer>();
+    use_gpu |= true;
  }
-#endif  // __ANDROID__ || __EMSCRIPTEN__
+#endif  //  !MEDIAPIPE_DISABLE_GPU
  if (cc->Outputs().HasTag(kOutputFrameTag)) {
    cc->Outputs().Tag(kOutputFrameTag).Set<ImageFrame>();
  }

-#if defined(__ANDROID__) || defined(__EMSCRIPTEN__)
-  RETURN_IF_ERROR(mediapipe::GlCalculatorHelper::UpdateContract(cc));
-#endif  // __ANDROID__ || __EMSCRIPTEN__
+  if (use_gpu) {
+#if !defined(MEDIAPIPE_DISABLE_GPU)
+    MP_RETURN_IF_ERROR(mediapipe::GlCalculatorHelper::UpdateContract(cc));
+#endif  //  !MEDIAPIPE_DISABLE_GPU
+  }

  return ::mediapipe::OkStatus();
 }
@@ -166,11 +173,11 @@ REGISTER_CALCULATOR(BilateralFilterCalculator);

  if (cc->Inputs().HasTag(kInputFrameTagGpu) &&
      cc->Outputs().HasTag(kOutputFrameTagGpu)) {
-#if defined(__ANDROID__) || defined(__EMSCRIPTEN__)
+#if !defined(MEDIAPIPE_DISABLE_GPU)
    use_gpu_ = true;
 #else
-    RET_CHECK_FAIL() << "GPU processing on non-Android not supported yet.";
-#endif  // __ANDROID__ || __EMSCRIPTEN__
+    RET_CHECK_FAIL() << "GPU processing not enabled.";
+#endif
  }

  sigma_color_ = options_.sigma_color();
@@ -180,9 +187,9 @@ REGISTER_CALCULATOR(BilateralFilterCalculator);
  if (!use_gpu_) sigma_color_ *= 255.0;

  if (use_gpu_) {
-#if defined(__ANDROID__) || defined(__EMSCRIPTEN__)
-    RETURN_IF_ERROR(gpu_helper_.Open(cc));
-#endif
+#if !defined(MEDIAPIPE_DISABLE_GPU)
+    MP_RETURN_IF_ERROR(gpu_helper_.Open(cc));
+#endif  //  !MEDIAPIPE_DISABLE_GPU
  }

  return ::mediapipe::OkStatus();
@@ -190,33 +197,33 @@ REGISTER_CALCULATOR(BilateralFilterCalculator);

 ::mediapipe::Status BilateralFilterCalculator::Process(CalculatorContext* cc) {
  if (use_gpu_) {
-#if defined(__ANDROID__) || defined(__EMSCRIPTEN__)
-    RETURN_IF_ERROR(
+#if !defined(MEDIAPIPE_DISABLE_GPU)
+    MP_RETURN_IF_ERROR(
        gpu_helper_.RunInGlContext([this, cc]() -> ::mediapipe::Status {
          if (!gpu_initialized_) {
-            RETURN_IF_ERROR(GlSetup(cc));
+            MP_RETURN_IF_ERROR(GlSetup(cc));
            gpu_initialized_ = true;
          }
-          RETURN_IF_ERROR(RenderGpu(cc));
+          MP_RETURN_IF_ERROR(RenderGpu(cc));
          return ::mediapipe::OkStatus();
        }));
-#endif  // __ANDROID__ || __EMSCRIPTEN__
+#endif  //  !MEDIAPIPE_DISABLE_GPU
  } else {
-    RETURN_IF_ERROR(RenderCpu(cc));
+    MP_RETURN_IF_ERROR(RenderCpu(cc));
  }

  return ::mediapipe::OkStatus();
 }

 ::mediapipe::Status BilateralFilterCalculator::Close(CalculatorContext* cc) {
-#if defined(__ANDROID__) || defined(__EMSCRIPTEN__)
+#if !defined(MEDIAPIPE_DISABLE_GPU)
  gpu_helper_.RunInGlContext([this] {
    if (program_) glDeleteProgram(program_);
    program_ = 0;
    if (program_joint_) glDeleteProgram(program_joint_);
    program_joint_ = 0;
  });
-#endif  // __ANDROID__ || __EMSCRIPTEN__
+#endif  //  !MEDIAPIPE_DISABLE_GPU

  return ::mediapipe::OkStatus();
 }
@@ -263,7 +270,7 @@ REGISTER_CALCULATOR(BilateralFilterCalculator);
  if (cc->Inputs().Tag(kInputFrameTagGpu).IsEmpty()) {
    return ::mediapipe::OkStatus();
  }
-#if defined(__ANDROID__) || defined(__EMSCRIPTEN__)
+#if !defined(MEDIAPIPE_DISABLE_GPU)
  const auto& input_frame =
      cc->Inputs().Tag(kInputFrameTagGpu).Get<mediapipe::GpuBuffer>();
  auto input_texture = gpu_helper_.CreateSourceTexture(input_frame);
@@ -321,13 +328,13 @@ REGISTER_CALCULATOR(BilateralFilterCalculator);
  // Cleanup
  input_texture.Release();
  output_texture.Release();
-#endif  // __ANDROID__ || __EMSCRIPTEN__
+#endif  //  !MEDIAPIPE_DISABLE_GPU

  return ::mediapipe::OkStatus();
 }

 void BilateralFilterCalculator::GlRender(CalculatorContext* cc) {
-#if defined(__ANDROID__) || defined(__EMSCRIPTEN__)
+#if !defined(MEDIAPIPE_DISABLE_GPU)
  static const GLfloat square_vertices[] = {
      -1.0f, -1.0f,  // bottom left
      1.0f,  -1.0f,  // bottom right
@@ -373,11 +380,11 @@ void BilateralFilterCalculator::GlRender(CalculatorContext* cc) {
  glDeleteVertexArrays(1, &vao);
  glDeleteBuffers(2, vbo);

-#endif  // __ANDROID__ || __EMSCRIPTEN__
+#endif  //  !MEDIAPIPE_DISABLE_GPU
 }

 ::mediapipe::Status BilateralFilterCalculator::GlSetup(CalculatorContext* cc) {
-#if defined(__ANDROID__) || defined(__EMSCRIPTEN__)
+#if !defined(MEDIAPIPE_DISABLE_GPU)
  const GLint attr_location[NUM_ATTRIBUTES] = {
      ATTRIB_VERTEX,
      ATTRIB_TEXTURE_POSITION,
@@ -545,7 +552,7 @@ void BilateralFilterCalculator::GlRender(CalculatorContext* cc) {
  glUniform1i(glGetUniformLocation(program_joint_, "input_frame"), 1);
  glUniform1i(glGetUniformLocation(program_joint_, "guide_frame"), 2);

-#endif  // __ANDROID__ || __EMSCRIPTEN__
+#endif  //  !MEDIAPIPE_DISABLE_GPU

  return ::mediapipe::OkStatus();
 }
@@ -75,6 +75,11 @@ class ColorConvertCalculator : public CalculatorBase {
  static ::mediapipe::Status GetContract(CalculatorContract* cc);
  ::mediapipe::Status Process(CalculatorContext* cc) override;

+  ::mediapipe::Status Open(CalculatorContext* cc) override {
+    cc->SetOffset(TimestampDiff(0));
+    return ::mediapipe::OkStatus();
+  }
+
 private:
  // Wrangles the appropriate inputs and outputs to perform the color
  // conversion. The ImageFrame on input_tag is converted using the
@@ -0,0 +1,210 @@
+// Copyright 2020 The MediaPipe Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include <memory>
+#include <vector>
+
+#include "absl/memory/memory.h"
+#include "absl/synchronization/blocking_counter.h"
+#include "mediapipe/calculators/image/feature_detector_calculator.pb.h"
+#include "mediapipe/framework/calculator_framework.h"
+#include "mediapipe/framework/formats/image_frame.h"
+#include "mediapipe/framework/formats/image_frame_opencv.h"
+#include "mediapipe/framework/formats/landmark.pb.h"
+#include "mediapipe/framework/formats/video_stream_header.h"
+#include "mediapipe/framework/port/integral_types.h"
+#include "mediapipe/framework/port/logging.h"
+#include "mediapipe/framework/port/opencv_core_inc.h"
+#include "mediapipe/framework/port/opencv_features2d_inc.h"
+#include "mediapipe/framework/port/opencv_imgproc_inc.h"
+#include "mediapipe/framework/port/ret_check.h"
+#include "mediapipe/framework/port/status.h"
+#include "mediapipe/framework/port/threadpool.h"
+#include "mediapipe/framework/tool/options_util.h"
+#include "tensorflow/lite/interpreter.h"
+
+namespace mediapipe {
+
+const char kOptionsTag[] = "OPTIONS";
+const int kPatchSize = 32;
+const int kNumThreads = 16;
+
+// A calculator to apply local feature detection.
+// Input stream:
+//   IMAGE: Input image frame of type ImageFrame from video stream.
+// Output streams:
+//   FEATURES: The detected keypoints from input image as vector<cv::KeyPoint>.
+//   PATCHES:  Optional output the extracted patches as vector<cv::Mat>
+class FeatureDetectorCalculator : public CalculatorBase {
+ public:
+  ~FeatureDetectorCalculator() override = default;
+
+  static ::mediapipe::Status GetContract(CalculatorContract* cc);
+
+  ::mediapipe::Status Open(CalculatorContext* cc) override;
+  ::mediapipe::Status Process(CalculatorContext* cc) override;
+
+ private:
+  FeatureDetectorCalculatorOptions options_;
+  cv::Ptr<cv::Feature2D> feature_detector_;
+  std::unique_ptr<::mediapipe::ThreadPool> pool_;
+
+  // Create image pyramid based on input image.
+  void ComputeImagePyramid(const cv::Mat& input_image,
+                           std::vector<cv::Mat>* image_pyramid);
+
+  // Extract the patch for single feature with image pyramid.
+  cv::Mat ExtractPatch(const cv::KeyPoint& feature,
+                       const std::vector<cv::Mat>& image_pyramid);
+};
+
+REGISTER_CALCULATOR(FeatureDetectorCalculator);
+
+::mediapipe::Status FeatureDetectorCalculator::GetContract(
+    CalculatorContract* cc) {
+  if (cc->Inputs().HasTag("IMAGE")) {
+    cc->Inputs().Tag("IMAGE").Set<ImageFrame>();
+  }
+  if (cc->Outputs().HasTag("FEATURES")) {
+    cc->Outputs().Tag("FEATURES").Set<std::vector<cv::KeyPoint>>();
+  }
+  if (cc->Outputs().HasTag("LANDMARKS")) {
+    cc->Outputs().Tag("LANDMARKS").Set<NormalizedLandmarkList>();
+  }
+  if (cc->Outputs().HasTag("PATCHES")) {
+    cc->Outputs().Tag("PATCHES").Set<std::vector<TfLiteTensor>>();
+  }
+  return ::mediapipe::OkStatus();
+}
+
+::mediapipe::Status FeatureDetectorCalculator::Open(CalculatorContext* cc) {
+  options_ =
+      tool::RetrieveOptions(cc->Options(), cc->InputSidePackets(), kOptionsTag)
+          .GetExtension(FeatureDetectorCalculatorOptions::ext);
+  feature_detector_ = cv::ORB::create(
+      options_.max_features(), options_.scale_factor(),
+      options_.pyramid_level(), kPatchSize - 1, 0, 2, cv::ORB::FAST_SCORE);
+  pool_ = absl::make_unique<::mediapipe::ThreadPool>("ThreadPool", kNumThreads);
+  pool_->StartWorkers();
+  return ::mediapipe::OkStatus();
+}
+
+::mediapipe::Status FeatureDetectorCalculator::Process(CalculatorContext* cc) {
+  const Timestamp& timestamp = cc->InputTimestamp();
+  if (timestamp == Timestamp::PreStream()) {
+    // Indicator packet.
+    return ::mediapipe::OkStatus();
+  }
+  InputStream* input_frame = &(cc->Inputs().Tag("IMAGE"));
+  cv::Mat input_view = formats::MatView(&input_frame->Get<ImageFrame>());
+  cv::Mat grayscale_view;
+  cv::cvtColor(input_view, grayscale_view, cv::COLOR_RGB2GRAY);
+
+  std::vector<cv::KeyPoint> keypoints;
+  feature_detector_->detect(grayscale_view, keypoints);
+  if (keypoints.size() > options_.max_features()) {
+    keypoints.resize(options_.max_features());
+  }
+
+  if (cc->Outputs().HasTag("FEATURES")) {
+    auto features_ptr = absl::make_unique<std::vector<cv::KeyPoint>>(keypoints);
+    cc->Outputs().Tag("FEATURES").Add(features_ptr.release(), timestamp);
+  }
+
+  if (cc->Outputs().HasTag("LANDMARKS")) {
+    auto landmarks_ptr = absl::make_unique<NormalizedLandmarkList>();
+    for (int j = 0; j < keypoints.size(); ++j) {
+      auto feature_landmark = landmarks_ptr->add_landmark();
+      feature_landmark->set_x(keypoints[j].pt.x / grayscale_view.cols);
+      feature_landmark->set_y(keypoints[j].pt.y / grayscale_view.rows);
+    }
+    cc->Outputs().Tag("LANDMARKS").Add(landmarks_ptr.release(), timestamp);
+  }
+
+  if (cc->Outputs().HasTag("PATCHES")) {
+    std::vector<cv::Mat> image_pyramid;
+    ComputeImagePyramid(grayscale_view, &image_pyramid);
+    std::vector<cv::Mat> patch_mat;
+    patch_mat.resize(keypoints.size());
+    absl::BlockingCounter counter(keypoints.size());
+    for (int i = 0; i < keypoints.size(); i++) {
+      pool_->Schedule(
+          [this, &image_pyramid, &keypoints, &patch_mat, i, &counter] {
+            patch_mat[i] = ExtractPatch(keypoints[i], image_pyramid);
+            counter.DecrementCount();
+          });
+    }
+    counter.Wait();
+    const int batch_size = options_.max_features();
+    auto patches = absl::make_unique<std::vector<TfLiteTensor>>();
+    TfLiteTensor tensor;
+    tensor.type = kTfLiteFloat32;
+    tensor.dims = TfLiteIntArrayCreate(4);
+    tensor.dims->data[0] = batch_size;
+    tensor.dims->data[1] = kPatchSize;
+    tensor.dims->data[2] = kPatchSize;
+    tensor.dims->data[3] = 1;
+    int num_bytes = batch_size * kPatchSize * kPatchSize * sizeof(float);
+    tensor.data.data = malloc(num_bytes);
+    tensor.bytes = num_bytes;
+    tensor.allocation_type = kTfLiteArenaRw;
+    float* tensor_buffer = tensor.data.f;
+    for (int i = 0; i < keypoints.size(); i++) {
+      for (int j = 0; j < patch_mat[i].rows; ++j) {
+        for (int k = 0; k < patch_mat[i].cols; ++k) {
+          *tensor_buffer++ = patch_mat[i].at<uchar>(j, k) / 128.0f - 1.0f;
+        }
+      }
+    }
+    for (int i = keypoints.size() * kPatchSize * kPatchSize; i < num_bytes / 4;
+         i++) {
+      *tensor_buffer++ = 0;
+    }
+
+    patches->emplace_back(tensor);
+    cc->Outputs().Tag("PATCHES").Add(patches.release(), timestamp);
+  }
+
+  return ::mediapipe::OkStatus();
+}
+
+void FeatureDetectorCalculator::ComputeImagePyramid(
+    const cv::Mat& input_image, std::vector<cv::Mat>* image_pyramid) {
+  cv::Mat tmp_image = input_image;
+  cv::Mat src_image = input_image;
+  for (int i = 0; i < options_.pyramid_level(); ++i) {
+    image_pyramid->push_back(src_image);
+    cv::resize(src_image, tmp_image, cv::Size(), 1.0f / options_.scale_factor(),
+               1.0f / options_.scale_factor());
+    src_image = tmp_image;
+  }
+}
+
+cv::Mat FeatureDetectorCalculator::ExtractPatch(
+    const cv::KeyPoint& feature, const std::vector<cv::Mat>& image_pyramid) {
+  cv::Mat img = image_pyramid[feature.octave];
+  float scale_factor = 1 / pow(options_.scale_factor(), feature.octave);
+  cv::Point2f center =
+      cv::Point2f(feature.pt.x * scale_factor, feature.pt.y * scale_factor);
+  cv::Mat rot = cv::getRotationMatrix2D(center, feature.angle, 1.0);
+  rot.at<double>(0, 2) += kPatchSize / 2 - center.x;
+  rot.at<double>(1, 2) += kPatchSize / 2 - center.y;
+  cv::Mat cropped_img;
+  // perform the affine transformation
+  cv::warpAffine(img, cropped_img, rot, cv::Size(kPatchSize, kPatchSize),
+                 cv::INTER_LINEAR);
+  return cropped_img;
+}
+
+}  // namespace mediapipe
@@ -0,0 +1,24 @@
+// Options for FeatureDetectorCalculator
+syntax = "proto2";
+
+package mediapipe;
+
+import "mediapipe/framework/calculator.proto";
+
+message FeatureDetectorCalculatorOptions {
+  extend CalculatorOptions {
+    optional FeatureDetectorCalculatorOptions ext = 278741680;
+  }
+
+  // Set to true if output patches, otherwise only output cv::KeyPoint
+  optional bool output_patch = 1;
+
+  // The max number of detected features.
+  optional int32 max_features = 2 [default = 200];
+
+  // The number of pyramid levels.
+  optional int32 pyramid_level = 3 [default = 4];
+
+  // Pyramid decimation ratio.
+  optional float scale_factor = 4 [default = 1.2];
+}
@@ -12,10 +12,10 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.

+#include "mediapipe/calculators/image/image_cropping_calculator.h"
+
 #include <cmath>

-#include "mediapipe/calculators/image/image_cropping_calculator.pb.h"
-#include "mediapipe/framework/calculator_framework.h"
 #include "mediapipe/framework/formats/image_frame.h"
 #include "mediapipe/framework/formats/image_frame_opencv.h"
 #include "mediapipe/framework/formats/rect.pb.h"
@@ -24,12 +24,11 @@
 #include "mediapipe/framework/port/ret_check.h"
 #include "mediapipe/framework/port/status.h"

-#if defined(__ANDROID__) || (defined(__APPLE__) && !TARGET_OS_OSX)
-#include "mediapipe/gpu/gl_calculator_helper.h"
+#if !defined(MEDIAPIPE_DISABLE_GPU)
 #include "mediapipe/gpu/gl_simple_shaders.h"
 #include "mediapipe/gpu/gpu_buffer.h"
 #include "mediapipe/gpu/shader_util.h"
-#endif  // __ANDROID__ or iOS
+#endif  //  !MEDIAPIPE_DISABLE_GPU

 namespace {
 enum { ATTRIB_VERTEX, ATTRIB_TEXTURE_POSITION, NUM_ATTRIBUTES };
@@ -37,102 +36,85 @@ enum { ATTRIB_VERTEX, ATTRIB_TEXTURE_POSITION, NUM_ATTRIBUTES };

 namespace mediapipe {

-#if defined(__ANDROID__) || (defined(__APPLE__) && !TARGET_OS_OSX)
+namespace {

-#endif  // __ANDROID__ or iOS
+#if !defined(MEDIAPIPE_DISABLE_GPU)

-// Crops the input texture to the given rectangle region. The rectangle can
-// be at arbitrary location on the image with rotation. If there's rotation, the
-// output texture will have the size of the input rectangle. The rotation should
-// be in radian, see rect.proto for detail.
-//
-// Input:
-//   One of the following two tags:
-//   IMAGE - ImageFrame representing the input image.
-//   IMAGE_GPU - GpuBuffer representing the input image.
-//   One of the following two tags (optional if WIDTH/HEIGHT is specified):
-//   RECT - A Rect proto specifying the width/height and location of the
-//          cropping rectangle.
-//   NORM_RECT - A NormalizedRect proto specifying the width/height and location
-//               of the cropping rectangle in normalized coordinates.
-//   Alternative tags to RECT (optional if RECT/NORM_RECT is specified):
-//   WIDTH - The desired width of the output cropped image,
-//           based on image center
-//   HEIGHT - The desired height of the output cropped image,
-//            based on image center
-//
-// Output:
-//   One of the following two tags:
-//   IMAGE - Cropped ImageFrame
-//   IMAGE_GPU - Cropped GpuBuffer.
-//
-// Note: input_stream values take precedence over options defined in the graph.
-//
-class ImageCroppingCalculator : public CalculatorBase {
- public:
-  ImageCroppingCalculator() = default;
-  ~ImageCroppingCalculator() override = default;
+#endif  //  !MEDIAPIPE_DISABLE_GPU

-  static ::mediapipe::Status GetContract(CalculatorContract* cc);
-  ::mediapipe::Status Open(CalculatorContext* cc) override;
-  ::mediapipe::Status Process(CalculatorContext* cc) override;
-  ::mediapipe::Status Close(CalculatorContext* cc) override;
+constexpr char kRectTag[] = "RECT";
+constexpr char kNormRectTag[] = "NORM_RECT";
+constexpr char kHeightTag[] = "HEIGHT";
+constexpr char kImageTag[] = "IMAGE";
+constexpr char kImageGpuTag[] = "IMAGE_GPU";
+constexpr char kWidthTag[] = "WIDTH";

- private:
-  ::mediapipe::Status RenderCpu(CalculatorContext* cc);
-  ::mediapipe::Status RenderGpu(CalculatorContext* cc);
-  ::mediapipe::Status InitGpu(CalculatorContext* cc);
-  void GlRender();
-  void GetOutputDimensions(CalculatorContext* cc, int src_width, int src_height,
-                           int* dst_width, int* dst_height);
+}  // namespace

-  mediapipe::ImageCroppingCalculatorOptions options_;
-
-  bool use_gpu_ = false;
-  // Output texture corners (4) after transoformation in normalized coordinates.
-  float transformed_points_[8];
-#if defined(__ANDROID__) || (defined(__APPLE__) && !TARGET_OS_OSX)
-  bool gpu_initialized_ = false;
-  mediapipe::GlCalculatorHelper gpu_helper_;
-  GLuint program_ = 0;
-#endif  // __ANDROID__ or iOS
-};
 REGISTER_CALCULATOR(ImageCroppingCalculator);

 ::mediapipe::Status ImageCroppingCalculator::GetContract(
    CalculatorContract* cc) {
-  RET_CHECK(cc->Inputs().HasTag("IMAGE") ^ cc->Inputs().HasTag("IMAGE_GPU"));
-  RET_CHECK(cc->Outputs().HasTag("IMAGE") ^ cc->Outputs().HasTag("IMAGE_GPU"));
+  RET_CHECK(cc->Inputs().HasTag(kImageTag) ^ cc->Inputs().HasTag(kImageGpuTag));
+  RET_CHECK(cc->Outputs().HasTag(kImageTag) ^
+            cc->Outputs().HasTag(kImageGpuTag));

-  if (cc->Inputs().HasTag("IMAGE")) {
-    RET_CHECK(cc->Outputs().HasTag("IMAGE"));
-    cc->Inputs().Tag("IMAGE").Set<ImageFrame>();
-    cc->Outputs().Tag("IMAGE").Set<ImageFrame>();
-  }
-#if defined(__ANDROID__) || (defined(__APPLE__) && !TARGET_OS_OSX)
-  if (cc->Inputs().HasTag("IMAGE_GPU")) {
-    RET_CHECK(cc->Outputs().HasTag("IMAGE_GPU"));
-    cc->Inputs().Tag("IMAGE_GPU").Set<GpuBuffer>();
-    cc->Outputs().Tag("IMAGE_GPU").Set<GpuBuffer>();
-  }
-#endif  // __ANDROID__ or iOS
+  bool use_gpu = false;

-  if (cc->Inputs().HasTag("RECT")) {
-    cc->Inputs().Tag("RECT").Set<Rect>();
+  if (cc->Inputs().HasTag(kImageTag)) {
+    RET_CHECK(cc->Outputs().HasTag(kImageTag));
+    cc->Inputs().Tag(kImageTag).Set<ImageFrame>();
+    cc->Outputs().Tag(kImageTag).Set<ImageFrame>();
  }
-  if (cc->Inputs().HasTag("NORM_RECT")) {
-    cc->Inputs().Tag("NORM_RECT").Set<NormalizedRect>();
+#if !defined(MEDIAPIPE_DISABLE_GPU)
+  if (cc->Inputs().HasTag(kImageGpuTag)) {
+    RET_CHECK(cc->Outputs().HasTag(kImageGpuTag));
+    cc->Inputs().Tag(kImageGpuTag).Set<GpuBuffer>();
+    cc->Outputs().Tag(kImageGpuTag).Set<GpuBuffer>();
+    use_gpu |= true;
  }
-  if (cc->Inputs().HasTag("WIDTH")) {
-    cc->Inputs().Tag("WIDTH").Set<int>();
+#endif  //  !MEDIAPIPE_DISABLE_GPU
+
+  int flags = 0;
+  if (cc->Inputs().HasTag(kRectTag)) {
+    ++flags;
  }
-  if (cc->Inputs().HasTag("HEIGHT")) {
-    cc->Inputs().Tag("HEIGHT").Set<int>();
+  if (cc->Inputs().HasTag(kWidthTag) && cc->Inputs().HasTag(kHeightTag)) {
+    ++flags;
+  }
+  if (cc->Inputs().HasTag(kNormRectTag)) {
+    ++flags;
+  }
+  if (cc->Options<mediapipe::ImageCroppingCalculatorOptions>()
+          .has_norm_width() &&
+      cc->Options<mediapipe::ImageCroppingCalculatorOptions>()
+          .has_norm_height()) {
+    ++flags;
+  }
+  if (cc->Options<mediapipe::ImageCroppingCalculatorOptions>().has_width() &&
+      cc->Options<mediapipe::ImageCroppingCalculatorOptions>().has_height()) {
+    ++flags;
+  }
+  RET_CHECK(flags == 1) << "Illegal combination of input streams/options.";
+
+  if (cc->Inputs().HasTag(kRectTag)) {
+    cc->Inputs().Tag(kRectTag).Set<Rect>();
+  }
+  if (cc->Inputs().HasTag(kNormRectTag)) {
+    cc->Inputs().Tag(kNormRectTag).Set<NormalizedRect>();
+  }
+  if (cc->Inputs().HasTag(kWidthTag)) {
+    cc->Inputs().Tag(kWidthTag).Set<int>();
+  }
+  if (cc->Inputs().HasTag(kHeightTag)) {
+    cc->Inputs().Tag(kHeightTag).Set<int>();
  }

-#if defined(__ANDROID__) || (defined(__APPLE__) && !TARGET_OS_OSX)
-  RETURN_IF_ERROR(mediapipe::GlCalculatorHelper::UpdateContract(cc));
-#endif  // __ANDROID__ or iOS
+  if (use_gpu) {
+#if !defined(MEDIAPIPE_DISABLE_GPU)
+    MP_RETURN_IF_ERROR(mediapipe::GlCalculatorHelper::UpdateContract(cc));
+#endif  //  !MEDIAPIPE_DISABLE_GPU
+  }

  return ::mediapipe::OkStatus();
 }
@@ -140,93 +122,111 @@ REGISTER_CALCULATOR(ImageCroppingCalculator);
 ::mediapipe::Status ImageCroppingCalculator::Open(CalculatorContext* cc) {
  cc->SetOffset(TimestampDiff(0));

-  if (cc->Inputs().HasTag("IMAGE_GPU")) {
+  if (cc->Inputs().HasTag(kImageGpuTag)) {
    use_gpu_ = true;
  }

  options_ = cc->Options<mediapipe::ImageCroppingCalculatorOptions>();

  if (use_gpu_) {
-#if defined(__ANDROID__) || (defined(__APPLE__) && !TARGET_OS_OSX)
-    RETURN_IF_ERROR(gpu_helper_.Open(cc));
+#if !defined(MEDIAPIPE_DISABLE_GPU)
+    MP_RETURN_IF_ERROR(gpu_helper_.Open(cc));
 #else
    RET_CHECK_FAIL() << "GPU processing is for Android and iOS only.";
-#endif  // __ANDROID__ or iOS
+#endif  //  !MEDIAPIPE_DISABLE_GPU
+  }
+
+  // Validate border mode.
+  if (use_gpu_) {
+    MP_RETURN_IF_ERROR(ValidateBorderModeForGPU(cc));
+  } else {
+    MP_RETURN_IF_ERROR(ValidateBorderModeForCPU(cc));
  }

  return ::mediapipe::OkStatus();
 }

 ::mediapipe::Status ImageCroppingCalculator::Process(CalculatorContext* cc) {
+  if (cc->Inputs().HasTag(kRectTag) && cc->Inputs().Tag(kRectTag).IsEmpty()) {
+    VLOG(1) << "RECT is empty for timestamp: " << cc->InputTimestamp();
+    return ::mediapipe::OkStatus();
+  }
+  if (cc->Inputs().HasTag(kNormRectTag) &&
+      cc->Inputs().Tag(kNormRectTag).IsEmpty()) {
+    VLOG(1) << "NORM_RECT is empty for timestamp: " << cc->InputTimestamp();
+    return ::mediapipe::OkStatus();
+  }
  if (use_gpu_) {
-#if defined(__ANDROID__) || (defined(__APPLE__) && !TARGET_OS_OSX)
-    RETURN_IF_ERROR(
+#if !defined(MEDIAPIPE_DISABLE_GPU)
+    MP_RETURN_IF_ERROR(
        gpu_helper_.RunInGlContext([this, cc]() -> ::mediapipe::Status {
          if (!gpu_initialized_) {
-            RETURN_IF_ERROR(InitGpu(cc));
+            MP_RETURN_IF_ERROR(InitGpu(cc));
            gpu_initialized_ = true;
          }
-          RETURN_IF_ERROR(RenderGpu(cc));
+          MP_RETURN_IF_ERROR(RenderGpu(cc));
          return ::mediapipe::OkStatus();
        }));
-#endif  // __ANDROID__ or iOS
+#endif  //  !MEDIAPIPE_DISABLE_GPU
  } else {
-    RETURN_IF_ERROR(RenderCpu(cc));
+    MP_RETURN_IF_ERROR(RenderCpu(cc));
  }
  return ::mediapipe::OkStatus();
 }

 ::mediapipe::Status ImageCroppingCalculator::Close(CalculatorContext* cc) {
-#if defined(__ANDROID__) || (defined(__APPLE__) && !TARGET_OS_OSX)
+#if !defined(MEDIAPIPE_DISABLE_GPU)
  gpu_helper_.RunInGlContext([this] {
    if (program_) glDeleteProgram(program_);
    program_ = 0;
  });
  gpu_initialized_ = false;
-#endif  // __ANDROID__ or iOS
+#endif  //  !MEDIAPIPE_DISABLE_GPU
+
+  return ::mediapipe::OkStatus();
+}
+
+::mediapipe::Status ImageCroppingCalculator::ValidateBorderModeForCPU(
+    CalculatorContext* cc) {
+  int border_mode;
+  return GetBorderModeForOpenCV(cc, &border_mode);
+}
+
+::mediapipe::Status ImageCroppingCalculator::ValidateBorderModeForGPU(
+    CalculatorContext* cc) {
+  mediapipe::ImageCroppingCalculatorOptions options =
+      cc->Options<mediapipe::ImageCroppingCalculatorOptions>();
+
+  switch (options.border_mode()) {
+    case mediapipe::ImageCroppingCalculatorOptions::BORDER_ZERO:
+      LOG(WARNING) << "BORDER_ZERO mode is not supported by GPU "
+                   << "implementation and will fall back into BORDER_REPLICATE";
+      break;
+    case mediapipe::ImageCroppingCalculatorOptions::BORDER_REPLICATE:
+      break;
+    default:
+      RET_CHECK_FAIL() << "Unsupported border mode for GPU: "
+                       << options.border_mode();
+  }

  return ::mediapipe::OkStatus();
 }

 ::mediapipe::Status ImageCroppingCalculator::RenderCpu(CalculatorContext* cc) {
-  const auto& input_img = cc->Inputs().Tag("IMAGE").Get<ImageFrame>();
+  if (cc->Inputs().Tag(kImageTag).IsEmpty()) {
+    return ::mediapipe::OkStatus();
+  }
+  const auto& input_img = cc->Inputs().Tag(kImageTag).Get<ImageFrame>();
  cv::Mat input_mat = formats::MatView(&input_img);

-  float rect_center_x = input_img.Width() / 2.0f;
-  float rect_center_y = input_img.Height() / 2.0f;
-  float rotation = 0.0f;
-  int target_width = input_img.Width();
-  int target_height = input_img.Height();
-  if (cc->Inputs().HasTag("RECT")) {
-    const auto& rect = cc->Inputs().Tag("RECT").Get<Rect>();
-    if (rect.width() > 0 && rect.height() > 0 && rect.x_center() >= 0 &&
-        rect.y_center() >= 0) {
-      rect_center_x = rect.x_center();
-      rect_center_y = rect.y_center();
-      target_width = rect.width();
-      target_height = rect.height();
-      rotation = rect.rotation();
-    }
-  } else if (cc->Inputs().HasTag("NORM_RECT")) {
-    const auto& rect = cc->Inputs().Tag("NORM_RECT").Get<NormalizedRect>();
-    if (rect.width() > 0.0 && rect.height() > 0.0 && rect.x_center() >= 0.0 &&
-        rect.y_center() >= 0.0) {
-      rect_center_x = std::round(rect.x_center() * input_img.Width());
-      rect_center_y = std::round(rect.y_center() * input_img.Height());
-      target_width = std::round(rect.width() * input_img.Width());
-      target_height = std::round(rect.height() * input_img.Height());
-      rotation = rect.rotation();
-    }
-  } else {
-    if (cc->Inputs().HasTag("WIDTH") && cc->Inputs().HasTag("HEIGHT")) {
-      target_width = cc->Inputs().Tag("WIDTH").Get<int>();
-      target_height = cc->Inputs().Tag("HEIGHT").Get<int>();
-    } else if (options_.has_width() && options_.has_height()) {
-      target_width = options_.width();
-      target_height = options_.height();
-    }
-    rotation = options_.rotation();
-  }
+  RectSpec specs = GetCropSpecs(cc, input_img.Width(), input_img.Height());
+  int target_width = specs.width, target_height = specs.height,
+      rect_center_x = specs.center_x, rect_center_y = specs.center_y;
+  float rotation = specs.rotation;
+
+  // Get border mode and value for OpenCV.
+  int border_mode;
+  MP_RETURN_IF_ERROR(GetBorderModeForOpenCV(cc, &border_mode));

  const cv::RotatedRect min_rect(cv::Point2f(rect_center_x, rect_center_y),
                                 cv::Size2f(target_width, target_height),
@@ -247,22 +247,25 @@ REGISTER_CALCULATOR(ImageCroppingCalculator);
      cv::getPerspectiveTransform(src_points, dst_points);
  cv::Mat cropped_image;
  cv::warpPerspective(input_mat, cropped_image, projection_matrix,
-                      cv::Size(min_rect.size.width, min_rect.size.height));
+                      cv::Size(min_rect.size.width, min_rect.size.height),
+                      /* flags = */ 0,
+                      /* borderMode = */ border_mode);

  std::unique_ptr<ImageFrame> output_frame(new ImageFrame(
      input_img.Format(), cropped_image.cols, cropped_image.rows));
  cv::Mat output_mat = formats::MatView(output_frame.get());
  cropped_image.copyTo(output_mat);
-  cc->Outputs().Tag("IMAGE").Add(output_frame.release(), cc->InputTimestamp());
+  cc->Outputs().Tag(kImageTag).Add(output_frame.release(),
+                                   cc->InputTimestamp());
  return ::mediapipe::OkStatus();
 }

 ::mediapipe::Status ImageCroppingCalculator::RenderGpu(CalculatorContext* cc) {
-  if (cc->Inputs().Tag("IMAGE_GPU").IsEmpty()) {
+  if (cc->Inputs().Tag(kImageGpuTag).IsEmpty()) {
    return ::mediapipe::OkStatus();
  }
-#if defined(__ANDROID__) || (defined(__APPLE__) && !TARGET_OS_OSX)
-  const Packet& input_packet = cc->Inputs().Tag("IMAGE_GPU").Value();
+#if !defined(MEDIAPIPE_DISABLE_GPU)
+  const Packet& input_packet = cc->Inputs().Tag(kImageGpuTag).Value();
  const auto& input_buffer = input_packet.Get<mediapipe::GpuBuffer>();
  auto src_tex = gpu_helper_.CreateSourceTexture(input_buffer);

@@ -287,18 +290,18 @@ REGISTER_CALCULATOR(ImageCroppingCalculator);

  // Send result image in GPU packet.
  auto output = dst_tex.GetFrame<mediapipe::GpuBuffer>();
-  cc->Outputs().Tag("IMAGE_GPU").Add(output.release(), cc->InputTimestamp());
+  cc->Outputs().Tag(kImageGpuTag).Add(output.release(), cc->InputTimestamp());

  // Cleanup
  src_tex.Release();
  dst_tex.Release();
-#endif  // __ANDROID__ or iOS
+#endif  //  !MEDIAPIPE_DISABLE_GPU

  return ::mediapipe::OkStatus();
 }

 void ImageCroppingCalculator::GlRender() {
-#if defined(__ANDROID__) || (defined(__APPLE__) && !TARGET_OS_OSX)
+#if !defined(MEDIAPIPE_DISABLE_GPU)
  static const GLfloat square_vertices[] = {
      -1.0f, -1.0f,  // bottom left
      1.0f,  -1.0f,  // bottom right
@@ -342,11 +345,11 @@ void ImageCroppingCalculator::GlRender() {
  glDeleteVertexArrays(1, &vao);
  glDeleteBuffers(2, vbo);

-#endif  // __ANDROID__ or iOS
+#endif  //  !MEDIAPIPE_DISABLE_GPU
 }

 ::mediapipe::Status ImageCroppingCalculator::InitGpu(CalculatorContext* cc) {
-#if defined(__ANDROID__) || (defined(__APPLE__) && !TARGET_OS_OSX)
+#if !defined(MEDIAPIPE_DISABLE_GPU)
  const GLint attr_location[NUM_ATTRIBUTES] = {
      ATTRIB_VERTEX,
      ATTRIB_TEXTURE_POSITION,
@@ -392,7 +395,7 @@ void ImageCroppingCalculator::GlRender() {
  // Parameters
  glUseProgram(program_);
  glUniform1i(glGetUniformLocation(program_, "input_frame"), 1);
-#endif  // __ANDROID__ or iOS
+#endif  //  !MEDIAPIPE_DISABLE_GPU

  return ::mediapipe::OkStatus();
 }
@@ -402,46 +405,10 @@ void ImageCroppingCalculator::GetOutputDimensions(CalculatorContext* cc,
                                                  int src_width, int src_height,
                                                  int* dst_width,
                                                  int* dst_height) {
-  // Get the size of the cropping box.
-  int crop_width = src_width;
-  int crop_height = src_height;
-  // Get the center of cropping box. Default is the at the center.
-  int x_center = src_width / 2;
-  int y_center = src_height / 2;
-  // Get the rotation of the cropping box.
-  float rotation = 0.0f;
-  if (cc->Inputs().HasTag("RECT")) {
-    const auto& rect = cc->Inputs().Tag("RECT").Get<Rect>();
-    // Only use the rect if it is valid.
-    if (rect.width() > 0 && rect.height() > 0 && rect.x_center() >= 0 &&
-        rect.y_center() >= 0) {
-      x_center = rect.x_center();
-      y_center = rect.y_center();
-      crop_width = rect.width();
-      crop_height = rect.height();
-      rotation = rect.rotation();
-    }
-  } else if (cc->Inputs().HasTag("NORM_RECT")) {
-    const auto& rect = cc->Inputs().Tag("NORM_RECT").Get<NormalizedRect>();
-    // Only use the rect if it is valid.
-    if (rect.width() > 0.0 && rect.height() > 0.0 && rect.x_center() >= 0.0 &&
-        rect.y_center() >= 0.0) {
-      x_center = std::round(rect.x_center() * src_width);
-      y_center = std::round(rect.y_center() * src_height);
-      crop_width = std::round(rect.width() * src_width);
-      crop_height = std::round(rect.height() * src_height);
-      rotation = rect.rotation();
-    }
-  } else {
-    if (cc->Inputs().HasTag("WIDTH") && cc->Inputs().HasTag("HEIGHT")) {
-      crop_width = cc->Inputs().Tag("WIDTH").Get<int>();
-      crop_height = cc->Inputs().Tag("HEIGHT").Get<int>();
-    } else if (options_.has_width() && options_.has_height()) {
-      crop_width = options_.width();
-      crop_height = options_.height();
-    }
-    rotation = options_.rotation();
-  }
+  RectSpec specs = GetCropSpecs(cc, src_width, src_height);
+  int crop_width = specs.width, crop_height = specs.height,
+      x_center = specs.center_x, y_center = specs.center_y;
+  float rotation = specs.rotation;

  const float half_width = crop_width / 2.0f;
  const float half_height = crop_height / 2.0f;
@@ -470,8 +437,110 @@ void ImageCroppingCalculator::GetOutputDimensions(CalculatorContext* cc,
    row_max = std::max(row_max, transformed_points_[i * 2 + 1]);
  }

-  *dst_width = std::round((col_max - col_min) * src_width);
-  *dst_height = std::round((row_max - row_min) * src_height);
+  int width = static_cast<int>(std::round((col_max - col_min) * src_width));
+  int height = static_cast<int>(std::round((row_max - row_min) * src_height));
+  // Minimum output dimension 1x1 prevents creation of textures with 0x0.
+  *dst_width = std::max(1, width);
+  *dst_height = std::max(1, height);
+}
+
+RectSpec ImageCroppingCalculator::GetCropSpecs(const CalculatorContext* cc,
+                                               int src_width, int src_height) {
+  // Get the size of the cropping box.
+  int crop_width = src_width;
+  int crop_height = src_height;
+  // Get the center of cropping box. Default is the at the center.
+  int x_center = src_width / 2;
+  int y_center = src_height / 2;
+  // Get the rotation of the cropping box.
+  float rotation = 0.0f;
+  // Get the normalized width and height if specified by the inputs or options.
+  float normalized_width = 0.0f;
+  float normalized_height = 0.0f;
+
+  mediapipe::ImageCroppingCalculatorOptions options =
+      cc->Options<mediapipe::ImageCroppingCalculatorOptions>();
+
+  // width/height, norm_width/norm_height from input streams take precednece.
+  if (cc->Inputs().HasTag(kRectTag)) {
+    const auto& rect = cc->Inputs().Tag(kRectTag).Get<Rect>();
+    // Only use the rect if it is valid.
+    if (rect.width() > 0 && rect.height() > 0 && rect.x_center() >= 0 &&
+        rect.y_center() >= 0) {
+      x_center = rect.x_center();
+      y_center = rect.y_center();
+      crop_width = rect.width();
+      crop_height = rect.height();
+      rotation = rect.rotation();
+    }
+  } else if (cc->Inputs().HasTag(kNormRectTag)) {
+    const auto& norm_rect =
+        cc->Inputs().Tag(kNormRectTag).Get<NormalizedRect>();
+    if (norm_rect.width() > 0.0 && norm_rect.height() > 0.0) {
+      normalized_width = norm_rect.width();
+      normalized_height = norm_rect.height();
+      x_center = std::round(norm_rect.x_center() * src_width);
+      y_center = std::round(norm_rect.y_center() * src_height);
+      rotation = norm_rect.rotation();
+    }
+  } else if (cc->Inputs().HasTag(kWidthTag) &&
+             cc->Inputs().HasTag(kHeightTag)) {
+    crop_width = cc->Inputs().Tag(kWidthTag).Get<int>();
+    crop_height = cc->Inputs().Tag(kHeightTag).Get<int>();
+  } else if (options.has_width() && options.has_height()) {
+    crop_width = options.width();
+    crop_height = options.height();
+  } else if (options.has_norm_width() && options.has_norm_height()) {
+    normalized_width = options.norm_width();
+    normalized_height = options.norm_height();
+  }
+
+  // Get the crop width and height from the normalized width and height.
+  if (normalized_width > 0 && normalized_height > 0) {
+    crop_width = std::round(normalized_width * src_width);
+    crop_height = std::round(normalized_height * src_height);
+  }
+
+  // Rotation and center values from input streams take precedence, so only
+  // look at those values in the options if kRectTag and kNormRectTag are not
+  // present from the inputs.
+  if (!cc->Inputs().HasTag(kRectTag) && !cc->Inputs().HasTag(kNormRectTag)) {
+    if (options.has_norm_center_x() && options.has_norm_center_y()) {
+      x_center = std::round(options.norm_center_x() * src_width);
+      y_center = std::round(options.norm_center_y() * src_height);
+    }
+    if (options.has_rotation()) {
+      rotation = options.rotation();
+    }
+  }
+
+  return {
+      .width = crop_width,
+      .height = crop_height,
+      .center_x = x_center,
+      .center_y = y_center,
+      .rotation = rotation,
+  };
+}
+
+::mediapipe::Status ImageCroppingCalculator::GetBorderModeForOpenCV(
+    CalculatorContext* cc, int* border_mode) {
+  mediapipe::ImageCroppingCalculatorOptions options =
+      cc->Options<mediapipe::ImageCroppingCalculatorOptions>();
+
+  switch (options.border_mode()) {
+    case mediapipe::ImageCroppingCalculatorOptions::BORDER_ZERO:
+      *border_mode = cv::BORDER_CONSTANT;
+      break;
+    case mediapipe::ImageCroppingCalculatorOptions::BORDER_REPLICATE:
+      *border_mode = cv::BORDER_REPLICATE;
+      break;
+    default:
+      RET_CHECK_FAIL() << "Unsupported border mode for CPU: "
+                       << options.border_mode();
+  }
+
+  return ::mediapipe::OkStatus();
 }

 }  // namespace mediapipe
@@ -0,0 +1,91 @@
+#ifndef MEDIAPIPE_CALCULATORS_IMAGE_IMAGE_CROPPING_CALCULATOR_H_
+#define MEDIAPIPE_CALCULATORS_IMAGE_IMAGE_CROPPING_CALCULATOR_H_
+
+#include "mediapipe/calculators/image/image_cropping_calculator.pb.h"
+#include "mediapipe/framework/calculator_framework.h"
+
+#if !defined(MEDIAPIPE_DISABLE_GPU)
+#include "mediapipe/gpu/gl_calculator_helper.h"
+#endif  //  !MEDIAPIPE_DISABLE_GPU
+
+// Crops the input texture to the given rectangle region. The rectangle can
+// be at arbitrary location on the image with rotation. If there's rotation, the
+// output texture will have the size of the input rectangle. The rotation should
+// be in radian, see rect.proto for detail.
+//
+// Input:
+//   One of the following two tags:
+//   IMAGE - ImageFrame representing the input image.
+//   IMAGE_GPU - GpuBuffer representing the input image.
+//   One of the following two tags (optional if WIDTH/HEIGHT is specified):
+//   RECT - A Rect proto specifying the width/height and location of the
+//          cropping rectangle.
+//   NORM_RECT - A NormalizedRect proto specifying the width/height and location
+//               of the cropping rectangle in normalized coordinates.
+//   Alternative tags to RECT (optional if RECT/NORM_RECT is specified):
+//   WIDTH - The desired width of the output cropped image,
+//           based on image center
+//   HEIGHT - The desired height of the output cropped image,
+//            based on image center
+//
+// Output:
+//   One of the following two tags:
+//   IMAGE - Cropped ImageFrame
+//   IMAGE_GPU - Cropped GpuBuffer.
+//
+// Note: input_stream values take precedence over options defined in the graph.
+//
+namespace mediapipe {
+
+struct RectSpec {
+  int width;
+  int height;
+  int center_x;
+  int center_y;
+  float rotation;
+
+  bool operator==(const RectSpec& rect) const {
+    return (width == rect.width && height == rect.height &&
+            center_x == rect.center_x && center_y == rect.center_y &&
+            rotation == rect.rotation);
+  }
+};
+
+class ImageCroppingCalculator : public CalculatorBase {
+ public:
+  ImageCroppingCalculator() = default;
+  ~ImageCroppingCalculator() override = default;
+
+  static ::mediapipe::Status GetContract(CalculatorContract* cc);
+  ::mediapipe::Status Open(CalculatorContext* cc) override;
+  ::mediapipe::Status Process(CalculatorContext* cc) override;
+  ::mediapipe::Status Close(CalculatorContext* cc) override;
+  static RectSpec GetCropSpecs(const CalculatorContext* cc, int src_width,
+                               int src_height);
+
+ private:
+  ::mediapipe::Status ValidateBorderModeForCPU(CalculatorContext* cc);
+  ::mediapipe::Status ValidateBorderModeForGPU(CalculatorContext* cc);
+  ::mediapipe::Status RenderCpu(CalculatorContext* cc);
+  ::mediapipe::Status RenderGpu(CalculatorContext* cc);
+  ::mediapipe::Status InitGpu(CalculatorContext* cc);
+  void GlRender();
+  void GetOutputDimensions(CalculatorContext* cc, int src_width, int src_height,
+                           int* dst_width, int* dst_height);
+  ::mediapipe::Status GetBorderModeForOpenCV(CalculatorContext* cc,
+                                             int* border_mode);
+
+  mediapipe::ImageCroppingCalculatorOptions options_;
+
+  bool use_gpu_ = false;
+  // Output texture corners (4) after transoformation in normalized coordinates.
+  float transformed_points_[8];
+#if !defined(MEDIAPIPE_DISABLE_GPU)
+  bool gpu_initialized_ = false;
+  mediapipe::GlCalculatorHelper gpu_helper_;
+  GLuint program_ = 0;
+#endif  //  !MEDIAPIPE_DISABLE_GPU
+};
+
+}  // namespace mediapipe
+#endif  // MEDIAPIPE_CALCULATORS_IMAGE_IMAGE_CROPPING_CALCULATOR_H_
@@ -30,4 +30,25 @@ message ImageCroppingCalculatorOptions {

  // Rotation angle is counter-clockwise in radian.
  optional float rotation = 3 [default = 0.0];
+
+  // Normalized width and height of the output rect. Value is within [0, 1].
+  optional float norm_width = 4;
+  optional float norm_height = 5;
+
+  // Normalized location of the center of the output
+  // rectangle in image coordinates. Value is within [0, 1].
+  // The (0, 0) point is at the (top, left) corner.
+  optional float norm_center_x = 6 [default = 0];
+  optional float norm_center_y = 7 [default = 0];
+
+  enum BorderMode {
+    // First unspecified value is required by the guideline. See details here:
+    // https://developers.google.com/protocol-buffers/docs/style#enums
+    BORDER_UNSPECIFIED = 0;
+    BORDER_ZERO = 1;
+    BORDER_REPLICATE = 2;
+  }
+
+  // Specifies behaviour for crops that go beyond image borders.
+  optional BorderMode border_mode = 8 [default = BORDER_ZERO];
 }
@@ -0,0 +1,216 @@
+// Copyright 2020 The MediaPipe Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "mediapipe/calculators/image/image_cropping_calculator.h"
+
+#include <cmath>
+#include <memory>
+
+#include "mediapipe/calculators/image/image_cropping_calculator.pb.h"
+#include "mediapipe/framework/calculator_framework.h"
+#include "mediapipe/framework/formats/rect.pb.h"
+#include "mediapipe/framework/port/gtest.h"
+#include "mediapipe/framework/port/parse_text_proto.h"
+#include "mediapipe/framework/port/status_matchers.h"
+#include "mediapipe/framework/tool/tag_map.h"
+#include "mediapipe/framework/tool/tag_map_helper.h"
+
+namespace mediapipe {
+
+namespace {
+
+constexpr int input_width = 100;
+constexpr int input_height = 100;
+
+constexpr char kRectTag[] = "RECT";
+constexpr char kHeightTag[] = "HEIGHT";
+constexpr char kWidthTag[] = "WIDTH";
+
+// Test normal case, where norm_width and norm_height in options are set.
+TEST(ImageCroppingCalculatorTest, GetCroppingDimensionsNormal) {
+  auto calculator_node =
+      ParseTextProtoOrDie<mediapipe::CalculatorGraphConfig::Node>(
+          R"(
+            calculator: "ImageCroppingCalculator"
+            input_stream: "IMAGE_GPU:input_frames"
+            output_stream: "IMAGE_GPU:cropped_output_frames"
+            options: {
+              [mediapipe.ImageCroppingCalculatorOptions.ext] {
+                norm_width: 0.6
+                norm_height: 0.6
+                norm_center_x: 0.5
+                norm_center_y: 0.5
+                rotation: 0.3
+              }
+            }
+          )");
+
+  auto calculator_state = absl::make_unique<CalculatorState>(
+      "Node", 0, "Calculator", calculator_node, nullptr);
+  auto cc = absl::make_unique<CalculatorContext>(
+      calculator_state.get(), tool::CreateTagMap({}).ValueOrDie(),
+      tool::CreateTagMap({}).ValueOrDie());
+
+  RectSpec expectRect = {
+      .width = 60,
+      .height = 60,
+      .center_x = 50,
+      .center_y = 50,
+      .rotation = 0.3,
+  };
+  EXPECT_EQ(ImageCroppingCalculator::GetCropSpecs(cc.get(), input_width,
+                                                  input_height),
+            expectRect);
+}  // TEST
+
+// Test when (width height) + (norm_width norm_height) are set in options.
+// width and height should take precedence.
+TEST(ImageCroppingCalculatorTest, RedundantSpecInOptions) {
+  auto calculator_node =
+      ParseTextProtoOrDie<mediapipe::CalculatorGraphConfig::Node>(
+          R"(
+            calculator: "ImageCroppingCalculator"
+            input_stream: "IMAGE_GPU:input_frames"
+            output_stream: "IMAGE_GPU:cropped_output_frames"
+            options: {
+              [mediapipe.ImageCroppingCalculatorOptions.ext] {
+                width: 50
+                height: 50
+                norm_width: 0.6
+                norm_height: 0.6
+                norm_center_x: 0.5
+                norm_center_y: 0.5
+                rotation: 0.3
+              }
+            }
+          )");
+
+  auto calculator_state = absl::make_unique<CalculatorState>(
+      "Node", 0, "Calculator", calculator_node, nullptr);
+  auto cc = absl::make_unique<CalculatorContext>(
+      calculator_state.get(), tool::CreateTagMap({}).ValueOrDie(),
+      tool::CreateTagMap({}).ValueOrDie());
+  RectSpec expectRect = {
+      .width = 50,
+      .height = 50,
+      .center_x = 50,
+      .center_y = 50,
+      .rotation = 0.3,
+  };
+  EXPECT_EQ(ImageCroppingCalculator::GetCropSpecs(cc.get(), input_width,
+                                                  input_height),
+            expectRect);
+}  // TEST
+
+// Test when WIDTH HEIGHT are set from input stream,
+// and options has norm_width/height set.
+// WIDTH HEIGHT from input stream should take precedence.
+TEST(ImageCroppingCalculatorTest, RedundantSpectWithInputStream) {
+  auto calculator_node =
+      ParseTextProtoOrDie<mediapipe::CalculatorGraphConfig::Node>(
+          R"(
+            calculator: "ImageCroppingCalculator"
+            input_stream: "IMAGE_GPU:input_frames"
+            input_stream: "WIDTH:crop_width"
+            input_stream: "HEIGHT:crop_height"
+            output_stream: "IMAGE_GPU:cropped_output_frames"
+            options: {
+              [mediapipe.ImageCroppingCalculatorOptions.ext] {
+                width: 50
+                height: 50
+                norm_width: 0.6
+                norm_height: 0.6
+                norm_center_x: 0.5
+                norm_center_y: 0.5
+                rotation: 0.3
+              }
+            }
+          )");
+
+  auto calculator_state = absl::make_unique<CalculatorState>(
+      "Node", 0, "Calculator", calculator_node, nullptr);
+  auto inputTags = tool::CreateTagMap({
+                                          "HEIGHT:0:crop_height",
+                                          "WIDTH:0:crop_width",
+                                      })
+                       .ValueOrDie();
+  auto cc = absl::make_unique<CalculatorContext>(
+      calculator_state.get(), inputTags, tool::CreateTagMap({}).ValueOrDie());
+  auto& inputs = cc->Inputs();
+  inputs.Tag(kHeightTag).Value() = MakePacket<int>(1);
+  inputs.Tag(kWidthTag).Value() = MakePacket<int>(1);
+  RectSpec expectRect = {
+      .width = 1,
+      .height = 1,
+      .center_x = 50,
+      .center_y = 50,
+      .rotation = 0.3,
+  };
+  EXPECT_EQ(ImageCroppingCalculator::GetCropSpecs(cc.get(), input_width,
+                                                  input_height),
+            expectRect);
+}  // TEST
+
+// Test when RECT is set from input stream,
+// and options has norm_width/height set.
+// RECT from input stream should take precedence.
+TEST(ImageCroppingCalculatorTest, RedundantSpecWithInputStream) {
+  auto calculator_node =
+      ParseTextProtoOrDie<mediapipe::CalculatorGraphConfig::Node>(
+          R"(
+            calculator: "ImageCroppingCalculator"
+            input_stream: "IMAGE_GPU:input_frames"
+            input_stream: "RECT:rect"
+            output_stream: "IMAGE_GPU:cropped_output_frames"
+            options: {
+              [mediapipe.ImageCroppingCalculatorOptions.ext] {
+                width: 50
+                height: 50
+                norm_width: 0.6
+                norm_height: 0.6
+                norm_center_x: 0.5
+                norm_center_y: 0.5
+                rotation: 0.3
+              }
+            }
+          )");
+
+  auto calculator_state = absl::make_unique<CalculatorState>(
+      "Node", 0, "Calculator", calculator_node, nullptr);
+  auto inputTags = tool::CreateTagMap({
+                                          "RECT:0:rect",
+                                      })
+                       .ValueOrDie();
+  auto cc = absl::make_unique<CalculatorContext>(
+      calculator_state.get(), inputTags, tool::CreateTagMap({}).ValueOrDie());
+  auto& inputs = cc->Inputs();
+  mediapipe::Rect rect = ParseTextProtoOrDie<mediapipe::Rect>(
+      R"(
+        width: 1 height: 1 x_center: 40 y_center: 40 rotation: 0.5
+      )");
+  inputs.Tag(kRectTag).Value() = MakePacket<mediapipe::Rect>(rect);
+  RectSpec expectRect = {
+      .width = 1,
+      .height = 1,
+      .center_x = 40,
+      .center_y = 40,
+      .rotation = 0.5,
+  };
+  EXPECT_EQ(ImageCroppingCalculator::GetCropSpecs(cc.get(), input_width,
+                                                  input_height),
+            expectRect);
+}  // TEST
+
+}  // namespace
+}  // namespace mediapipe
@@ -15,9 +15,9 @@
 #include "mediapipe/framework/calculator_framework.h"
 #include "mediapipe/framework/formats/image_frame.h"

-#if defined(__ANDROID__) || (defined(__APPLE__) && !TARGET_OS_OSX)
+#if !defined(MEDIAPIPE_DISABLE_GPU)
 #include "mediapipe/gpu/gpu_buffer.h"
-#endif  // __ANDROID__ or iOS
+#endif  //  !MEDIAPIPE_DISABLE_GPU

 namespace mediapipe {

@@ -44,11 +44,11 @@ class ImagePropertiesCalculator : public CalculatorBase {
    if (cc->Inputs().HasTag("IMAGE")) {
      cc->Inputs().Tag("IMAGE").Set<ImageFrame>();
    }
-#if defined(__ANDROID__) || (defined(__APPLE__) && !TARGET_OS_OSX)
+#if !defined(MEDIAPIPE_DISABLE_GPU)
    if (cc->Inputs().HasTag("IMAGE_GPU")) {
      cc->Inputs().Tag("IMAGE_GPU").Set<::mediapipe::GpuBuffer>();
    }
-#endif  // __ANDROID__ or iOS
+#endif  //  !MEDIAPIPE_DISABLE_GPU

    if (cc->Outputs().HasTag("SIZE")) {
      cc->Outputs().Tag("SIZE").Set<std::pair<int, int>>();
@@ -71,7 +71,7 @@ class ImagePropertiesCalculator : public CalculatorBase {
      width = image.Width();
      height = image.Height();
    }
-#if defined(__ANDROID__) || (defined(__APPLE__) && !TARGET_OS_OSX)
+#if !defined(MEDIAPIPE_DISABLE_GPU)
    if (cc->Inputs().HasTag("IMAGE_GPU") &&
        !cc->Inputs().Tag("IMAGE_GPU").IsEmpty()) {
      const auto& image =
@@ -79,7 +79,7 @@ class ImagePropertiesCalculator : public CalculatorBase {
      width = image.width();
      height = image.height();
    }
-#endif  // __ANDROID__ or iOS
+#endif  //  !MEDIAPIPE_DISABLE_GPU

    cc->Outputs().Tag("SIZE").AddPacket(
        MakePacket<std::pair<int, int>>(width, height)
@@ -22,12 +22,12 @@
 #include "mediapipe/framework/port/status.h"
 #include "mediapipe/gpu/scale_mode.pb.h"

-#if defined(__ANDROID__) || defined(__APPLE__) && !TARGET_OS_OSX
+#if !defined(MEDIAPIPE_DISABLE_GPU)
 #include "mediapipe/gpu/gl_calculator_helper.h"
 #include "mediapipe/gpu/gl_quad_renderer.h"
 #include "mediapipe/gpu/gl_simple_shaders.h"
 #include "mediapipe/gpu/shader_util.h"
-#endif  // __ANDROID__ || iOS
+#endif  //  !MEDIAPIPE_DISABLE_GPU

 #if defined(__ANDROID__)
 // The size of Java arrays is dynamic, which makes it difficult to
@@ -42,9 +42,9 @@ typedef int DimensionsPacketType[2];

 namespace mediapipe {

-#if defined(__ANDROID__) || defined(__APPLE__) && !TARGET_OS_OSX
+#if !defined(MEDIAPIPE_DISABLE_GPU)

-#endif  // __ANDROID__ || iOS
+#endif  //  !MEDIAPIPE_DISABLE_GPU

 namespace {
 int RotationModeToDegrees(mediapipe::RotationMode_Mode rotation) {
@@ -104,6 +104,14 @@ mediapipe::ScaleMode_Mode ParseScaleMode(
 //   to be a multiple of 90 degrees. If provided, it overrides the
 //   ROTATION_DEGREES input side packet.
 //
+//   FLIP_HORIZONTALLY (optional): Whether to flip image horizontally or not. If
+//   provided, it overrides the FLIP_HORIZONTALLY input side packet and/or
+//   corresponding field in the calculator options.
+//
+//   FLIP_VERTICALLY (optional): Whether to flip image vertically or not. If
+//   provided, it overrides the FLIP_VERTICALLY input side packet and/or
+//   corresponding field in the calculator options.
+//
 // Output:
 //   One of the following two tags:
 //   IMAGE - ImageFrame representing the output image.
@@ -129,6 +137,12 @@ mediapipe::ScaleMode_Mode ParseScaleMode(
 //   degrees. It has to be a multiple of 90 degrees. It overrides the
 //   corresponding field in the calculator options.
 //
+//   FLIP_HORIZONTALLY (optional): Whether to flip image horizontally or not.
+//   It overrides the corresponding field in the calculator options.
+//
+//   FLIP_VERTICALLY (optional): Whether to flip image vertically or not.
+//   It overrides the corresponding field in the calculator options.
+//
 // Calculator options (see image_transformation_calculator.proto):
 //   output_width, output_height - (optional) Desired scaled image size.
 //   rotation_mode - (optional) Rotation in multiples of 90 degrees.
@@ -138,8 +152,7 @@ mediapipe::ScaleMode_Mode ParseScaleMode(
 // Note: To enable horizontal or vertical flipping, specify them in the
 // calculator options. Flipping is applied after rotation.
 //
-// Note: Only scale mode STRETCH is currently supported on CPU,
-// and flipping is not yet supported either.
+// Note: Only scale mode STRETCH is currently supported on CPU.
 //
 class ImageTransformationCalculator : public CalculatorBase {
 public:
@@ -168,14 +181,16 @@ class ImageTransformationCalculator : public CalculatorBase {
  int output_height_ = 0;
  mediapipe::RotationMode_Mode rotation_;
  mediapipe::ScaleMode_Mode scale_mode_;
+  bool flip_horizontally_ = false;
+  bool flip_vertically_ = false;

  bool use_gpu_ = false;
-#if defined(__ANDROID__) || defined(__APPLE__) && !TARGET_OS_OSX
+#if !defined(MEDIAPIPE_DISABLE_GPU)
  GlCalculatorHelper helper_;
  std::unique_ptr<QuadRenderer> rgb_renderer_;
  std::unique_ptr<QuadRenderer> yuv_renderer_;
  std::unique_ptr<QuadRenderer> ext_rgb_renderer_;
-#endif  // __ANDROID__ || iOS
+#endif  //  !MEDIAPIPE_DISABLE_GPU
 };
 REGISTER_CALCULATOR(ImageTransformationCalculator);

@@ -185,21 +200,31 @@ REGISTER_CALCULATOR(ImageTransformationCalculator);
  RET_CHECK(cc->Inputs().HasTag("IMAGE") ^ cc->Inputs().HasTag("IMAGE_GPU"));
  RET_CHECK(cc->Outputs().HasTag("IMAGE") ^ cc->Outputs().HasTag("IMAGE_GPU"));

+  bool use_gpu = false;
+
  if (cc->Inputs().HasTag("IMAGE")) {
    RET_CHECK(cc->Outputs().HasTag("IMAGE"));
    cc->Inputs().Tag("IMAGE").Set<ImageFrame>();
    cc->Outputs().Tag("IMAGE").Set<ImageFrame>();
  }
-#if defined(__ANDROID__) || defined(__APPLE__) && !TARGET_OS_OSX
+#if !defined(MEDIAPIPE_DISABLE_GPU)
  if (cc->Inputs().HasTag("IMAGE_GPU")) {
    RET_CHECK(cc->Outputs().HasTag("IMAGE_GPU"));
    cc->Inputs().Tag("IMAGE_GPU").Set<GpuBuffer>();
    cc->Outputs().Tag("IMAGE_GPU").Set<GpuBuffer>();
+    use_gpu |= true;
  }
-#endif  // __ANDROID__ || iOS
+#endif  //  !MEDIAPIPE_DISABLE_GPU
+
  if (cc->Inputs().HasTag("ROTATION_DEGREES")) {
    cc->Inputs().Tag("ROTATION_DEGREES").Set<int>();
  }
+  if (cc->Inputs().HasTag("FLIP_HORIZONTALLY")) {
+    cc->Inputs().Tag("FLIP_HORIZONTALLY").Set<bool>();
+  }
+  if (cc->Inputs().HasTag("FLIP_VERTICALLY")) {
+    cc->Inputs().Tag("FLIP_VERTICALLY").Set<bool>();
+  }

  if (cc->InputSidePackets().HasTag("OUTPUT_DIMENSIONS")) {
    cc->InputSidePackets().Tag("OUTPUT_DIMENSIONS").Set<DimensionsPacketType>();
@@ -207,14 +232,22 @@ REGISTER_CALCULATOR(ImageTransformationCalculator);
  if (cc->InputSidePackets().HasTag("ROTATION_DEGREES")) {
    cc->InputSidePackets().Tag("ROTATION_DEGREES").Set<int>();
  }
+  if (cc->InputSidePackets().HasTag("FLIP_HORIZONTALLY")) {
+    cc->InputSidePackets().Tag("FLIP_HORIZONTALLY").Set<bool>();
+  }
+  if (cc->InputSidePackets().HasTag("FLIP_VERTICALLY")) {
+    cc->InputSidePackets().Tag("FLIP_VERTICALLY").Set<bool>();
+  }

  if (cc->Outputs().HasTag("LETTERBOX_PADDING")) {
    cc->Outputs().Tag("LETTERBOX_PADDING").Set<std::array<float, 4>>();
  }

-#if defined(__ANDROID__) || defined(__APPLE__) && !TARGET_OS_OSX
-  RETURN_IF_ERROR(GlCalculatorHelper::UpdateContract(cc));
-#endif  // __ANDROID__ || iOS
+  if (use_gpu) {
+#if !defined(MEDIAPIPE_DISABLE_GPU)
+    MP_RETURN_IF_ERROR(GlCalculatorHelper::UpdateContract(cc));
+#endif  //  !MEDIAPIPE_DISABLE_GPU
+  }

  return ::mediapipe::OkStatus();
 }
@@ -240,22 +273,37 @@ REGISTER_CALCULATOR(ImageTransformationCalculator);
    output_width_ = options_.output_width();
    output_height_ = options_.output_height();
  }
+
  if (cc->InputSidePackets().HasTag("ROTATION_DEGREES")) {
    rotation_ = DegreesToRotationMode(
        cc->InputSidePackets().Tag("ROTATION_DEGREES").Get<int>());
  } else {
-    rotation_ = DegreesToRotationMode(options_.rotation_mode());
+    rotation_ = options_.rotation_mode();
+  }
+
+  if (cc->InputSidePackets().HasTag("FLIP_HORIZONTALLY")) {
+    flip_horizontally_ =
+        cc->InputSidePackets().Tag("FLIP_HORIZONTALLY").Get<bool>();
+  } else {
+    flip_horizontally_ = options_.flip_horizontally();
+  }
+
+  if (cc->InputSidePackets().HasTag("FLIP_VERTICALLY")) {
+    flip_vertically_ =
+        cc->InputSidePackets().Tag("FLIP_VERTICALLY").Get<bool>();
+  } else {
+    flip_vertically_ = options_.flip_vertically();
  }

  scale_mode_ = ParseScaleMode(options_.scale_mode(), DEFAULT_SCALE_MODE);

  if (use_gpu_) {
-#if defined(__ANDROID__) || defined(__APPLE__) && !TARGET_OS_OSX
+#if !defined(MEDIAPIPE_DISABLE_GPU)
    // Let the helper access the GL context information.
-    RETURN_IF_ERROR(helper_.Open(cc));
+    MP_RETURN_IF_ERROR(helper_.Open(cc));
 #else
-    RET_CHECK_FAIL() << "GPU processing is for Android and iOS only.";
-#endif  // __ANDROID__ || iOS
+    RET_CHECK_FAIL() << "GPU processing not enabled.";
+#endif  //  !MEDIAPIPE_DISABLE_GPU
  }

  return ::mediapipe::OkStatus();
@@ -263,12 +311,37 @@ REGISTER_CALCULATOR(ImageTransformationCalculator);

 ::mediapipe::Status ImageTransformationCalculator::Process(
    CalculatorContext* cc) {
+  // Override values if specified so.
+  if (cc->Inputs().HasTag("ROTATION_DEGREES") &&
+      !cc->Inputs().Tag("ROTATION_DEGREES").IsEmpty()) {
+    rotation_ =
+        DegreesToRotationMode(cc->Inputs().Tag("ROTATION_DEGREES").Get<int>());
+  }
+  if (cc->Inputs().HasTag("FLIP_HORIZONTALLY") &&
+      !cc->Inputs().Tag("FLIP_HORIZONTALLY").IsEmpty()) {
+    flip_horizontally_ = cc->Inputs().Tag("FLIP_HORIZONTALLY").Get<bool>();
+  }
+  if (cc->Inputs().HasTag("FLIP_VERTICALLY") &&
+      !cc->Inputs().Tag("FLIP_VERTICALLY").IsEmpty()) {
+    flip_vertically_ = cc->Inputs().Tag("FLIP_VERTICALLY").Get<bool>();
+  }
+
  if (use_gpu_) {
-#if defined(__ANDROID__) || defined(__APPLE__) && !TARGET_OS_OSX
+#if !defined(MEDIAPIPE_DISABLE_GPU)
+    if (cc->Inputs().Tag("IMAGE_GPU").IsEmpty()) {
+      // Image is missing, hence no way to produce output image. (Timestamp
+      // bound will be updated automatically.)
+      return ::mediapipe::OkStatus();
+    }
    return helper_.RunInGlContext(
        [this, cc]() -> ::mediapipe::Status { return RenderGpu(cc); });
-#endif  // __ANDROID__ || iOS
+#endif  //  !MEDIAPIPE_DISABLE_GPU
  } else {
+    if (cc->Inputs().Tag("IMAGE").IsEmpty()) {
+      // Image is missing, hence no way to produce output image. (Timestamp
+      // bound will be updated automatically.)
+      return ::mediapipe::OkStatus();
+    }
    return RenderCpu(cc);
  }
  return ::mediapipe::OkStatus();
@@ -277,7 +350,7 @@ REGISTER_CALCULATOR(ImageTransformationCalculator);
 ::mediapipe::Status ImageTransformationCalculator::Close(
    CalculatorContext* cc) {
  if (use_gpu_) {
-#if defined(__ANDROID__) || defined(__APPLE__) && !TARGET_OS_OSX
+#if !defined(MEDIAPIPE_DISABLE_GPU)
    QuadRenderer* rgb_renderer = rgb_renderer_.release();
    QuadRenderer* yuv_renderer = yuv_renderer_.release();
    QuadRenderer* ext_rgb_renderer = ext_rgb_renderer_.release();
@@ -295,8 +368,9 @@ REGISTER_CALCULATOR(ImageTransformationCalculator);
        delete yuv_renderer;
      }
    });
-#endif  // __ANDROID__ || iOS
+#endif  //  !MEDIAPIPE_DISABLE_GPU
  }
+
  return ::mediapipe::OkStatus();
 }

@@ -309,6 +383,11 @@ REGISTER_CALCULATOR(ImageTransformationCalculator);
  cv::Mat input_mat = formats::MatView(&input_img);
  cv::Mat scaled_mat;

+  if (!output_height_ || !output_width_) {
+    output_height_ = input_height;
+    output_width_ = input_width;
+  }
+
  if (scale_mode_ == mediapipe::ScaleMode_Mode_STRETCH) {
    cv::resize(input_mat, scaled_mat, cv::Size(output_width_, output_height_));
  } else {
@@ -349,21 +428,25 @@ REGISTER_CALCULATOR(ImageTransformationCalculator);
        .Add(padding.release(), cc->InputTimestamp());
  }

-  if (cc->InputSidePackets().HasTag("ROTATION_DEGREES")) {
-    rotation_ = DegreesToRotationMode(
-        cc->InputSidePackets().Tag("ROTATION_DEGREES").Get<int>());
-  }
-
  cv::Mat rotated_mat;
  const int angle = RotationModeToDegrees(rotation_);
  cv::Point2f src_center(scaled_mat.cols / 2.0, scaled_mat.rows / 2.0);
  cv::Mat rotation_mat = cv::getRotationMatrix2D(src_center, angle, 1.0);
  cv::warpAffine(scaled_mat, rotated_mat, rotation_mat, scaled_mat.size());

+  cv::Mat flipped_mat;
+  if (flip_horizontally_ || flip_vertically_) {
+    const int flip_code =
+        flip_horizontally_ && flip_vertically_ ? -1 : flip_horizontally_;
+    cv::flip(rotated_mat, flipped_mat, flip_code);
+  } else {
+    flipped_mat = rotated_mat;
+  }
+
  std::unique_ptr<ImageFrame> output_frame(
      new ImageFrame(input_img.Format(), output_width, output_height));
  cv::Mat output_mat = formats::MatView(output_frame.get());
-  rotated_mat.copyTo(output_mat);
+  flipped_mat.copyTo(output_mat);
  cc->Outputs().Tag("IMAGE").Add(output_frame.release(), cc->InputTimestamp());

  return ::mediapipe::OkStatus();
@@ -371,7 +454,7 @@ REGISTER_CALCULATOR(ImageTransformationCalculator);

 ::mediapipe::Status ImageTransformationCalculator::RenderGpu(
    CalculatorContext* cc) {
-#if defined(__ANDROID__) || defined(__APPLE__) && !TARGET_OS_OSX
+#if !defined(MEDIAPIPE_DISABLE_GPU)
  int input_width = cc->Inputs().Tag("IMAGE_GPU").Get<GpuBuffer>().width();
  int input_height = cc->Inputs().Tag("IMAGE_GPU").Get<GpuBuffer>().height();

@@ -393,12 +476,12 @@ REGISTER_CALCULATOR(ImageTransformationCalculator);
  QuadRenderer* renderer = nullptr;
  GlTexture src1;

-#if defined(__APPLE__) && !TARGET_OS_OSX
+#if defined(MEDIAPIPE_IOS)
  if (input.format() == GpuBufferFormat::kBiPlanar420YpCbCr8VideoRange ||
      input.format() == GpuBufferFormat::kBiPlanar420YpCbCr8FullRange) {
    if (!yuv_renderer_) {
      yuv_renderer_ = absl::make_unique<QuadRenderer>();
-      RETURN_IF_ERROR(
+      MP_RETURN_IF_ERROR(
          yuv_renderer_->GlSetup(::mediapipe::kYUV2TexToRGBFragmentShader,
                                 {"video_frame_y", "video_frame_uv"}));
    }
@@ -408,34 +491,28 @@ REGISTER_CALCULATOR(ImageTransformationCalculator);
 #endif    // iOS
  {
    src1 = helper_.CreateSourceTexture(input);
-#if defined(__ANDROID__)
+#if defined(TEXTURE_EXTERNAL_OES)
    if (src1.target() == GL_TEXTURE_EXTERNAL_OES) {
      if (!ext_rgb_renderer_) {
        ext_rgb_renderer_ = absl::make_unique<QuadRenderer>();
-        RETURN_IF_ERROR(ext_rgb_renderer_->GlSetup(
+        MP_RETURN_IF_ERROR(ext_rgb_renderer_->GlSetup(
            ::mediapipe::kBasicTexturedFragmentShaderOES, {"video_frame"}));
      }
      renderer = ext_rgb_renderer_.get();
    } else  // NOLINT(readability/braces)
-#endif      // __ANDROID__
+#endif      // TEXTURE_EXTERNAL_OES
    {
      if (!rgb_renderer_) {
        rgb_renderer_ = absl::make_unique<QuadRenderer>();
-        RETURN_IF_ERROR(rgb_renderer_->GlSetup());
+        MP_RETURN_IF_ERROR(rgb_renderer_->GlSetup());
      }
      renderer = rgb_renderer_.get();
    }
  }
  RET_CHECK(renderer) << "Unsupported input texture type";

-  if (cc->InputSidePackets().HasTag("ROTATION_DEGREES")) {
-    rotation_ = DegreesToRotationMode(
-        cc->InputSidePackets().Tag("ROTATION_DEGREES").Get<int>());
-  }
-
-  static mediapipe::FrameScaleMode scale_mode =
-      mediapipe::FrameScaleModeFromProto(scale_mode_,
-                                         mediapipe::FrameScaleMode::kStretch);
+  mediapipe::FrameScaleMode scale_mode = mediapipe::FrameScaleModeFromProto(
+      scale_mode_, mediapipe::FrameScaleMode::kStretch);
  mediapipe::FrameRotation rotation =
      mediapipe::FrameRotationFromDegrees(RotationModeToDegrees(rotation_));

@@ -446,9 +523,9 @@ REGISTER_CALCULATOR(ImageTransformationCalculator);
  glActiveTexture(GL_TEXTURE1);
  glBindTexture(src1.target(), src1.name());

-  RETURN_IF_ERROR(renderer->GlRender(
+  MP_RETURN_IF_ERROR(renderer->GlRender(
      src1.width(), src1.height(), dst.width(), dst.height(), scale_mode,
-      rotation, options_.flip_horizontally(), options_.flip_vertically(),
+      rotation, flip_horizontally_, flip_vertically_,
      /*flip_texture=*/false));

  glActiveTexture(GL_TEXTURE1);
@@ -460,7 +537,7 @@ REGISTER_CALCULATOR(ImageTransformationCalculator);
  auto output = dst.GetFrame<GpuBuffer>();
  cc->Outputs().Tag("IMAGE_GPU").Add(output.release(), cc->InputTimestamp());

-#endif  // __ANDROID__ || iOS
+#endif  //  !MEDIAPIPE_DISABLE_GPU

  return ::mediapipe::OkStatus();
 }
@@ -74,7 +74,7 @@ REGISTER_CALCULATOR(MaskOverlayCalculator);

 // static
 ::mediapipe::Status MaskOverlayCalculator::GetContract(CalculatorContract* cc) {
-  RETURN_IF_ERROR(GlCalculatorHelper::UpdateContract(cc));
+  MP_RETURN_IF_ERROR(GlCalculatorHelper::UpdateContract(cc));
  cc->Inputs().Get("VIDEO", 0).Set<GpuBuffer>();
  cc->Inputs().Get("VIDEO", 1).Set<GpuBuffer>();
  if (cc->Inputs().HasTag("MASK"))
@@ -103,7 +103,7 @@ REGISTER_CALCULATOR(MaskOverlayCalculator);
      const auto& options = cc->Options<MaskOverlayCalculatorOptions>();
      const auto mask_channel = options.mask_channel();

-      RETURN_IF_ERROR(GlSetup(mask_channel));
+      MP_RETURN_IF_ERROR(GlSetup(mask_channel));
      initialized_ = true;
    }

@@ -147,7 +147,7 @@ REGISTER_CALCULATOR(MaskOverlayCalculator);
      glActiveTexture(GL_TEXTURE3);
      glBindTexture(mask_tex.target(), mask_tex.name());

-      RETURN_IF_ERROR(GlRender(mask_const));
+      MP_RETURN_IF_ERROR(GlRender(mask_const));

      glActiveTexture(GL_TEXTURE3);
      glBindTexture(mask_tex.target(), 0);
@@ -155,7 +155,7 @@ REGISTER_CALCULATOR(MaskOverlayCalculator);
    } else {
      const float mask_const = mask_packet.Get<float>();

-      RETURN_IF_ERROR(GlRender(mask_const));
+      MP_RETURN_IF_ERROR(GlRender(mask_const));
    }

    glActiveTexture(GL_TEXTURE2);
@@ -12,6 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.

+#include "mediapipe/calculators/image/opencv_encoded_image_to_image_frame_calculator.pb.h"
 #include "mediapipe/framework/calculator_framework.h"
 #include "mediapipe/framework/formats/image_frame_opencv.h"
 #include "mediapipe/framework/port/opencv_imgcodecs_inc.h"
@@ -34,7 +35,11 @@ namespace mediapipe {
 class OpenCvEncodedImageToImageFrameCalculator : public CalculatorBase {
 public:
  static ::mediapipe::Status GetContract(CalculatorContract* cc);
+  ::mediapipe::Status Open(CalculatorContext* cc) override;
  ::mediapipe::Status Process(CalculatorContext* cc) override;
+
+ private:
+  mediapipe::OpenCvEncodedImageToImageFrameCalculatorOptions options_;
 };

 ::mediapipe::Status OpenCvEncodedImageToImageFrameCalculator::GetContract(
@@ -44,13 +49,29 @@ class OpenCvEncodedImageToImageFrameCalculator : public CalculatorBase {
  return ::mediapipe::OkStatus();
 }

+::mediapipe::Status OpenCvEncodedImageToImageFrameCalculator::Open(
+    CalculatorContext* cc) {
+  options_ =
+      cc->Options<mediapipe::OpenCvEncodedImageToImageFrameCalculatorOptions>();
+  return ::mediapipe::OkStatus();
+}
+
 ::mediapipe::Status OpenCvEncodedImageToImageFrameCalculator::Process(
    CalculatorContext* cc) {
  const std::string& contents = cc->Inputs().Index(0).Get<std::string>();
  const std::vector<char> contents_vector(contents.begin(), contents.end());
-  cv::Mat decoded_mat =
-      cv::imdecode(contents_vector, -1 /* return the loaded image as-is */);
-
+  cv::Mat decoded_mat;
+  if (options_.apply_orientation_from_exif_data()) {
+    // We want to respect the orientation from the EXIF data, which
+    // IMREAD_UNCHANGED ignores, but otherwise we want to be as permissive as
+    // possible with our reading flags. Therefore, we use IMREAD_ANYCOLOR and
+    // IMREAD_ANYDEPTH.
+    decoded_mat = cv::imdecode(contents_vector,
+                               cv::IMREAD_ANYCOLOR | cv::IMREAD_ANYDEPTH);
+  } else {
+    // Return the loaded image as-is
+    decoded_mat = cv::imdecode(contents_vector, cv::IMREAD_UNCHANGED);
+  }
  ImageFormat::Format image_format = ImageFormat::UNKNOWN;
  cv::Mat output_mat;
  switch (decoded_mat.channels()) {
@@ -70,7 +91,8 @@ class OpenCvEncodedImageToImageFrameCalculator : public CalculatorBase {
             << "Unsupported number of channels: " << decoded_mat.channels();
  }
  std::unique_ptr<ImageFrame> output_frame = absl::make_unique<ImageFrame>(
-      image_format, decoded_mat.size().width, decoded_mat.size().height);
+      image_format, decoded_mat.size().width, decoded_mat.size().height,
+      ImageFrame::kGlDefaultAlignmentBoundary);
  output_mat.copyTo(formats::MatView(output_frame.get()));
  cc->Outputs().Index(0).Add(output_frame.release(), cc->InputTimestamp());
  return ::mediapipe::OkStatus();
@@ -0,0 +1,30 @@
+// Copyright 2020 The MediaPipe Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+syntax = "proto2";
+
+package mediapipe;
+
+import "mediapipe/framework/calculator.proto";
+
+message OpenCvEncodedImageToImageFrameCalculatorOptions {
+  extend CalculatorOptions {
+    optional OpenCvEncodedImageToImageFrameCalculatorOptions ext = 303447308;
+  }
+
+  // If set, we will attempt to automatically apply the orientation specified by
+  // the image's EXIF data when loading the image. Otherwise, the image data
+  // will be loaded as-is.
+  optional bool apply_orientation_from_exif_data = 1 [default = false];
+}
@@ -30,7 +30,7 @@ namespace {

 TEST(OpenCvEncodedImageToImageFrameCalculatorTest, TestRgbJpeg) {
  std::string contents;
-  MEDIAPIPE_ASSERT_OK(file::GetContents(
+  MP_ASSERT_OK(file::GetContents(
      file::JoinPath("./", "/mediapipe/calculators/image/testdata/dino.jpg"),
      &contents));
  Packet input_packet = MakePacket<std::string>(contents);
@@ -44,7 +44,7 @@ TEST(OpenCvEncodedImageToImageFrameCalculatorTest, TestRgbJpeg) {
  CalculatorRunner runner(node_config);
  runner.MutableInputs()->Index(0).packets.push_back(
      input_packet.At(Timestamp(0)));
-  MEDIAPIPE_ASSERT_OK(runner.Run());
+  MP_ASSERT_OK(runner.Run());
  const auto& outputs = runner.Outputs();
  ASSERT_EQ(1, outputs.NumEntries());
  const std::vector<Packet>& packets = outputs.Index(0).packets;
@@ -87,7 +87,7 @@ TEST(OpenCvEncodedImageToImageFrameCalculatorTest, TestGrayscaleJpeg) {
  CalculatorRunner runner(node_config);
  runner.MutableInputs()->Index(0).packets.push_back(
      input_packet.At(Timestamp(0)));
-  MEDIAPIPE_ASSERT_OK(runner.Run());
+  MP_ASSERT_OK(runner.Run());
  const auto& outputs = runner.Outputs();
  ASSERT_EQ(1, outputs.NumEntries());
  const std::vector<Packet>& packets = outputs.Index(0).packets;
@@ -55,7 +55,7 @@ TEST(OpenCvImageEncoderCalculatorTest, TestJpegWithQualities) {
    CalculatorRunner runner(node_config);
    runner.MutableInputs()->Index(0).packets.push_back(
        input_packet.At(Timestamp(0)));
-    MEDIAPIPE_ASSERT_OK(runner.Run());
+    MP_ASSERT_OK(runner.Run());
    const auto& outputs = runner.Outputs();
    ASSERT_EQ(1, outputs.NumEntries());
    const std::vector<Packet>& packets = outputs.Index(0).packets;
@@ -17,16 +17,18 @@
 #include "mediapipe/calculators/image/recolor_calculator.pb.h"
 #include "mediapipe/framework/calculator_framework.h"
 #include "mediapipe/framework/formats/image_frame.h"
+#include "mediapipe/framework/formats/image_frame_opencv.h"
+#include "mediapipe/framework/port/opencv_core_inc.h"
+#include "mediapipe/framework/port/opencv_imgproc_inc.h"
 #include "mediapipe/framework/port/ret_check.h"
 #include "mediapipe/framework/port/status.h"
 #include "mediapipe/util/color.pb.h"

-#if defined(__ANDROID__) || (defined(__APPLE__) && !TARGET_OS_OSX)
+#if !defined(MEDIAPIPE_DISABLE_GPU)
 #include "mediapipe/gpu/gl_calculator_helper.h"
 #include "mediapipe/gpu/gl_simple_shaders.h"
-#include "mediapipe/gpu/gpu_buffer.h"
 #include "mediapipe/gpu/shader_util.h"
-#endif  // __ANDROID__ or iOS
+#endif  //  !MEDIAPIPE_DISABLE_GPU

 namespace {
 enum { ATTRIB_VERTEX, ATTRIB_TEXTURE_POSITION, NUM_ATTRIBUTES };
@@ -40,8 +42,6 @@ namespace mediapipe {
 // The luminance of the input image is used to adjust the blending weight,
 // to help preserve image textures.
 //
-// TODO implement cpu support.
-//
 // Inputs:
 //   One of the following IMAGE tags:
 //   IMAGE: An ImageFrame input image, RGB or RGBA.
@@ -72,6 +72,8 @@ namespace mediapipe {
 //    }
 //  }
 //
+// Note: Cannot mix-match CPU & GPU inputs/outputs.
+//       CPU-in & CPU-out <or> GPU-in & GPU-out
 class RecolorCalculator : public CalculatorBase {
 public:
  RecolorCalculator() = default;
@@ -95,10 +97,10 @@ class RecolorCalculator : public CalculatorBase {
  mediapipe::RecolorCalculatorOptions::MaskChannel mask_channel_;

  bool use_gpu_ = false;
-#if defined(__ANDROID__) || (defined(__APPLE__) && !TARGET_OS_OSX)
+#if !defined(MEDIAPIPE_DISABLE_GPU)
  mediapipe::GlCalculatorHelper gpu_helper_;
  GLuint program_ = 0;
-#endif  // __ANDROID__ or iOS
+#endif  //  !MEDIAPIPE_DISABLE_GPU
 };
 REGISTER_CALCULATOR(RecolorCalculator);

@@ -107,36 +109,48 @@ REGISTER_CALCULATOR(RecolorCalculator);
  RET_CHECK(!cc->Inputs().GetTags().empty());
  RET_CHECK(!cc->Outputs().GetTags().empty());

-#if defined(__ANDROID__) || (defined(__APPLE__) && !TARGET_OS_OSX)
+  bool use_gpu = false;
+
+#if !defined(MEDIAPIPE_DISABLE_GPU)
  if (cc->Inputs().HasTag("IMAGE_GPU")) {
    cc->Inputs().Tag("IMAGE_GPU").Set<mediapipe::GpuBuffer>();
+    use_gpu |= true;
  }
-#endif  // __ANDROID__ or iOS
+#endif  //  !MEDIAPIPE_DISABLE_GPU
  if (cc->Inputs().HasTag("IMAGE")) {
    cc->Inputs().Tag("IMAGE").Set<ImageFrame>();
  }

-#if defined(__ANDROID__) || (defined(__APPLE__) && !TARGET_OS_OSX)
+#if !defined(MEDIAPIPE_DISABLE_GPU)
  if (cc->Inputs().HasTag("MASK_GPU")) {
    cc->Inputs().Tag("MASK_GPU").Set<mediapipe::GpuBuffer>();
+    use_gpu |= true;
  }
-#endif  // __ANDROID__ or iOS
+#endif  //  !MEDIAPIPE_DISABLE_GPU
  if (cc->Inputs().HasTag("MASK")) {
    cc->Inputs().Tag("MASK").Set<ImageFrame>();
  }

-#if defined(__ANDROID__) || (defined(__APPLE__) && !TARGET_OS_OSX)
+#if !defined(MEDIAPIPE_DISABLE_GPU)
  if (cc->Outputs().HasTag("IMAGE_GPU")) {
    cc->Outputs().Tag("IMAGE_GPU").Set<mediapipe::GpuBuffer>();
+    use_gpu |= true;
  }
-#endif  // __ANDROID__ or iOS
+#endif  //  !MEDIAPIPE_DISABLE_GPU
  if (cc->Outputs().HasTag("IMAGE")) {
    cc->Outputs().Tag("IMAGE").Set<ImageFrame>();
  }

-#if defined(__ANDROID__) || (defined(__APPLE__) && !TARGET_OS_OSX)
-  RETURN_IF_ERROR(mediapipe::GlCalculatorHelper::UpdateContract(cc));
-#endif  // __ANDROID__ or iOS
+  // Confirm only one of the input streams is present.
+  RET_CHECK(cc->Inputs().HasTag("IMAGE") ^ cc->Inputs().HasTag("IMAGE_GPU"));
+  // Confirm only one of the output streams is present.
+  RET_CHECK(cc->Outputs().HasTag("IMAGE") ^ cc->Outputs().HasTag("IMAGE_GPU"));
+
+  if (use_gpu) {
+#if !defined(MEDIAPIPE_DISABLE_GPU)
+    MP_RETURN_IF_ERROR(mediapipe::GlCalculatorHelper::UpdateContract(cc));
+#endif  //  !MEDIAPIPE_DISABLE_GPU
+  }

  return ::mediapipe::OkStatus();
 }
@@ -146,55 +160,110 @@ REGISTER_CALCULATOR(RecolorCalculator);

  if (cc->Inputs().HasTag("IMAGE_GPU")) {
    use_gpu_ = true;
-#if defined(__ANDROID__) || (defined(__APPLE__) && !TARGET_OS_OSX)
-    RETURN_IF_ERROR(gpu_helper_.Open(cc));
-#endif  // __ANDROID__ or iOS
+#if !defined(MEDIAPIPE_DISABLE_GPU)
+    MP_RETURN_IF_ERROR(gpu_helper_.Open(cc));
+#endif  //  !MEDIAPIPE_DISABLE_GPU
  }

-  RETURN_IF_ERROR(LoadOptions(cc));
+  MP_RETURN_IF_ERROR(LoadOptions(cc));

  return ::mediapipe::OkStatus();
 }

 ::mediapipe::Status RecolorCalculator::Process(CalculatorContext* cc) {
  if (use_gpu_) {
-#if defined(__ANDROID__) || (defined(__APPLE__) && !TARGET_OS_OSX)
-    RETURN_IF_ERROR(
+#if !defined(MEDIAPIPE_DISABLE_GPU)
+    MP_RETURN_IF_ERROR(
        gpu_helper_.RunInGlContext([this, &cc]() -> ::mediapipe::Status {
          if (!initialized_) {
-            RETURN_IF_ERROR(InitGpu(cc));
+            MP_RETURN_IF_ERROR(InitGpu(cc));
            initialized_ = true;
          }
-          RETURN_IF_ERROR(RenderGpu(cc));
+          MP_RETURN_IF_ERROR(RenderGpu(cc));
          return ::mediapipe::OkStatus();
        }));
-#endif  // __ANDROID__ or iOS
+#endif  //  !MEDIAPIPE_DISABLE_GPU
  } else {
-    RETURN_IF_ERROR(RenderCpu(cc));
+    MP_RETURN_IF_ERROR(RenderCpu(cc));
  }
  return ::mediapipe::OkStatus();
 }

 ::mediapipe::Status RecolorCalculator::Close(CalculatorContext* cc) {
-#if defined(__ANDROID__) || (defined(__APPLE__) && !TARGET_OS_OSX)
+#if !defined(MEDIAPIPE_DISABLE_GPU)
  gpu_helper_.RunInGlContext([this] {
    if (program_) glDeleteProgram(program_);
    program_ = 0;
  });
-#endif  // __ANDROID__ or iOS
+#endif  //  !MEDIAPIPE_DISABLE_GPU

  return ::mediapipe::OkStatus();
 }

 ::mediapipe::Status RecolorCalculator::RenderCpu(CalculatorContext* cc) {
-  return ::mediapipe::UnimplementedError("CPU support is not implemented yet.");
+  if (cc->Inputs().Tag("MASK").IsEmpty()) {
+    return ::mediapipe::OkStatus();
+  }
+  // Get inputs and setup output.
+  const auto& input_img = cc->Inputs().Tag("IMAGE").Get<ImageFrame>();
+  const auto& mask_img = cc->Inputs().Tag("MASK").Get<ImageFrame>();
+
+  cv::Mat input_mat = formats::MatView(&input_img);
+  cv::Mat mask_mat = formats::MatView(&mask_img);
+
+  RET_CHECK(input_mat.channels() == 3);  // RGB only.
+
+  if (mask_mat.channels() > 1) {
+    std::vector<cv::Mat> channels;
+    cv::split(mask_mat, channels);
+    if (mask_channel_ == mediapipe::RecolorCalculatorOptions_MaskChannel_ALPHA)
+      mask_mat = channels[3];
+    else
+      mask_mat = channels[0];
+  }
+  cv::Mat mask_full;
+  cv::resize(mask_mat, mask_full, input_mat.size());
+
+  auto output_img = absl::make_unique<ImageFrame>(
+      input_img.Format(), input_mat.cols, input_mat.rows);
+  cv::Mat output_mat = mediapipe::formats::MatView(output_img.get());
+
+  // From GPU shader:
+  /*
+      vec4 weight = texture2D(mask, sample_coordinate);
+      vec4 color1 = texture2D(frame, sample_coordinate);
+      vec4 color2 = vec4(recolor, 1.0);
+
+      float luminance = dot(color1.rgb, vec3(0.299, 0.587, 0.114));
+      float mix_value = weight.MASK_COMPONENT * luminance;
+
+      fragColor = mix(color1, color2, mix_value);
+  */
+  for (int i = 0; i < output_mat.rows; ++i) {
+    for (int j = 0; j < output_mat.cols; ++j) {
+      float weight = mask_full.at<uchar>(i, j) * (1.0 / 255.0);
+      cv::Vec3f color1 = input_mat.at<cv::Vec3b>(i, j);
+      cv::Vec3f color2 = {color_[0], color_[1], color_[2]};
+
+      float luminance =
+          (color1[0] * 0.299 + color1[1] * 0.587 + color1[2] * 0.114) / 255;
+      float mix_value = weight * luminance;
+
+      cv::Vec3b mix_color = color1 * (1.0 - mix_value) + color2 * mix_value;
+      output_mat.at<cv::Vec3b>(i, j) = mix_color;
+    }
+  }
+
+  cc->Outputs().Tag("IMAGE").Add(output_img.release(), cc->InputTimestamp());
+
+  return ::mediapipe::OkStatus();
 }

 ::mediapipe::Status RecolorCalculator::RenderGpu(CalculatorContext* cc) {
  if (cc->Inputs().Tag("MASK_GPU").IsEmpty()) {
    return ::mediapipe::OkStatus();
  }
-#if defined(__ANDROID__) || (defined(__APPLE__) && !TARGET_OS_OSX)
+#if !defined(MEDIAPIPE_DISABLE_GPU)
  // Get inputs and setup output.
  const Packet& input_packet = cc->Inputs().Tag("IMAGE_GPU").Value();
  const Packet& mask_packet = cc->Inputs().Tag("MASK_GPU").Value();
@@ -233,13 +302,13 @@ REGISTER_CALCULATOR(RecolorCalculator);
  img_tex.Release();
  mask_tex.Release();
  dst_tex.Release();
-#endif  // __ANDROID__ or iOS
+#endif  //  !MEDIAPIPE_DISABLE_GPU

  return ::mediapipe::OkStatus();
 }

 void RecolorCalculator::GlRender() {
-#if defined(__ANDROID__) || (defined(__APPLE__) && !TARGET_OS_OSX)
+#if !defined(MEDIAPIPE_DISABLE_GPU)
  static const GLfloat square_vertices[] = {
      -1.0f, -1.0f,  // bottom left
      1.0f,  -1.0f,  // bottom right
@@ -287,7 +356,7 @@ void RecolorCalculator::GlRender() {
  glBindVertexArray(0);
  glDeleteVertexArrays(1, &vao);
  glDeleteBuffers(2, vbo);
-#endif  // __ANDROID__ or iOS
+#endif  //  !MEDIAPIPE_DISABLE_GPU
 }

 ::mediapipe::Status RecolorCalculator::LoadOptions(CalculatorContext* cc) {
@@ -297,15 +366,15 @@ void RecolorCalculator::GlRender() {

  if (!options.has_color()) RET_CHECK_FAIL() << "Missing color option.";

-  color_.push_back(options.color().r() / 255.0);
-  color_.push_back(options.color().g() / 255.0);
-  color_.push_back(options.color().b() / 255.0);
+  color_.push_back(options.color().r());
+  color_.push_back(options.color().g());
+  color_.push_back(options.color().b());

  return ::mediapipe::OkStatus();
 }

 ::mediapipe::Status RecolorCalculator::InitGpu(CalculatorContext* cc) {
-#if defined(__ANDROID__) || (defined(__APPLE__) && !TARGET_OS_OSX)
+#if !defined(MEDIAPIPE_DISABLE_GPU)
  const GLint attr_location[NUM_ATTRIBUTES] = {
      ATTRIB_VERTEX,
      ATTRIB_TEXTURE_POSITION,
@@ -372,9 +441,9 @@ void RecolorCalculator::GlRender() {
  glUseProgram(program_);
  glUniform1i(glGetUniformLocation(program_, "frame"), 1);
  glUniform1i(glGetUniformLocation(program_, "mask"), 2);
-  glUniform3f(glGetUniformLocation(program_, "recolor"), color_[0], color_[1],
-              color_[2]);
-#endif  // __ANDROID__ or iOS
+  glUniform3f(glGetUniformLocation(program_, "recolor"), color_[0] / 255.0,
+              color_[1] / 255.0, color_[2] / 255.0);
+#endif  //  !MEDIAPIPE_DISABLE_GPU

  return ::mediapipe::OkStatus();
 }
@@ -253,21 +253,21 @@ ScaleImageCalculator::~ScaleImageCalculator() {}

 ::mediapipe::Status ScaleImageCalculator::InitializeFrameInfo(
    CalculatorContext* cc) {
-  RETURN_IF_ERROR(
+  MP_RETURN_IF_ERROR(
      scale_image::FindCropDimensions(input_width_, input_height_,  //
                                      options_.min_aspect_ratio(),  //
                                      options_.max_aspect_ratio(),  //
                                      &crop_width_, &crop_height_,  //
                                      &col_start_, &row_start_));
-  RETURN_IF_ERROR(
-      scale_image::FindOutputDimensions(crop_width_, crop_height_,            //
-                                        options_.target_width(),              //
-                                        options_.target_height(),             //
-                                        options_.preserve_aspect_ratio(),     //
-                                        options_.scale_to_multiple_of_two(),  //
+  MP_RETURN_IF_ERROR(
+      scale_image::FindOutputDimensions(crop_width_, crop_height_,         //
+                                        options_.target_width(),           //
+                                        options_.target_height(),          //
+                                        options_.preserve_aspect_ratio(),  //
+                                        options_.scale_to_multiple_of(),   //
                                        &output_width_, &output_height_));
-  RETURN_IF_ERROR(FindInterpolationAlgorithm(options_.algorithm(),
-                                             &interpolation_algorithm_));
+  MP_RETURN_IF_ERROR(FindInterpolationAlgorithm(options_.algorithm(),
+                                                &interpolation_algorithm_));
  if (interpolation_algorithm_ == -1 &&
      (output_width_ > crop_width_ || output_height_ > crop_height_)) {
    output_width_ = crop_width_;
@@ -327,7 +327,7 @@ ScaleImageCalculator::~ScaleImageCalculator() {}
  bool has_override_options = cc->Inputs().HasTag("OVERRIDE_OPTIONS");

  if (!has_override_options) {
-    RETURN_IF_ERROR(InitializeFromOptions());
+    MP_RETURN_IF_ERROR(InitializeFromOptions());
  }

  if (!cc->Inputs().Get(input_data_id_).Header().IsEmpty()) {
@@ -361,24 +361,28 @@ ScaleImageCalculator::~ScaleImageCalculator() {}
      output_format_ = input_format_;
    }

+    const bool is_positive_and_even =
+        (options_.scale_to_multiple_of() >= 1) &&
+        (options_.scale_to_multiple_of() % 2 == 0);
+
    if (output_format_ == ImageFormat::YCBCR420P) {
-      RET_CHECK(options_.scale_to_multiple_of_two())
+      RET_CHECK(is_positive_and_even)
          << "ScaleImageCalculator always outputs width and height that are "
             "divisible by 2 when output format is YCbCr420P. To scale to "
             "width and height of odd numbers, the output format must be SRGB.";
    } else if (options_.preserve_aspect_ratio()) {
-      RET_CHECK(options_.scale_to_multiple_of_two())
+      RET_CHECK(options_.scale_to_multiple_of() == 2)
          << "ScaleImageCalculator always outputs width and height that are "
-             "divisible by 2 when perserving aspect ratio. To scale to width "
-             "and height of odd numbers, please set "
-             "preserve_aspect_ratio to false.";
+             "divisible by 2 when preserving aspect ratio. If you'd like to "
+             "set scale_to_multiple_of to something other than 2, please "
+             "set preserve_aspect_ratio to false.";
    }

    if (input_width_ > 0 && input_height_ > 0 &&
        input_format_ != ImageFormat::UNKNOWN &&
        output_format_ != ImageFormat::UNKNOWN) {
-      RETURN_IF_ERROR(ValidateImageFormats());
-      RETURN_IF_ERROR(InitializeFrameInfo(cc));
+      MP_RETURN_IF_ERROR(ValidateImageFormats());
+      MP_RETURN_IF_ERROR(InitializeFrameInfo(cc));
      std::unique_ptr<VideoHeader> output_header(new VideoHeader());
      *output_header = input_video_header_;
      output_header->format = output_format_;
@@ -461,9 +465,9 @@ ScaleImageCalculator::~ScaleImageCalculator() {}
      } else {
        output_format_ = input_format_;
      }
-      RETURN_IF_ERROR(InitializeFrameInfo(cc));
+      MP_RETURN_IF_ERROR(InitializeFrameInfo(cc));
    }
-    RETURN_IF_ERROR(ValidateImageFormats());
+    MP_RETURN_IF_ERROR(ValidateImageFormats());
  } else {
    if (input_width_ != image_frame.Width() ||
        input_height_ != image_frame.Height()) {
@@ -474,13 +478,20 @@ ScaleImageCalculator::~ScaleImageCalculator() {}
          input_width_, "x", input_height_));
    }
    if (input_format_ != image_frame.Format()) {
+      std::string image_frame_format_desc, input_format_desc;
+#ifdef MEDIAPIPE_MOBILE
+      image_frame_format_desc = std::to_string(image_frame.Format());
+      input_format_desc = std::to_string(input_format_);
+#else
      const proto_ns::EnumDescriptor* desc = ImageFormat::Format_descriptor();
+      image_frame_format_desc =
+          desc->FindValueByNumber(image_frame.Format())->DebugString();
+      input_format_desc = desc->FindValueByNumber(input_format_)->DebugString();
+#endif  // MEDIAPIPE_MOBILE
      return tool::StatusFail(absl::StrCat(
          "If a header specifies a format, then image frames on "
          "the stream must have that format.  Actual format ",
-          desc->FindValueByNumber(image_frame.Format())->DebugString(),
-          " but expected ",
-          desc->FindValueByNumber(input_format_)->DebugString()));
+          image_frame_format_desc, " but expected ", input_format_desc));
    }
  }
  return ::mediapipe::OkStatus();
@@ -503,9 +514,9 @@ ScaleImageCalculator::~ScaleImageCalculator() {}
      } else {
        output_format_ = input_format_;
      }
-      RETURN_IF_ERROR(InitializeFrameInfo(cc));
+      MP_RETURN_IF_ERROR(InitializeFrameInfo(cc));
    }
-    RETURN_IF_ERROR(ValidateImageFormats());
+    MP_RETURN_IF_ERROR(ValidateImageFormats());
  } else {
    if (input_width_ != yuv_image.width() ||
        input_height_ != yuv_image.height()) {
@@ -531,7 +542,7 @@ ScaleImageCalculator::~ScaleImageCalculator() {}
      options_.MergeFrom(cc->Inputs()
                             .Tag("OVERRIDE_OPTIONS")
                             .Get<ScaleImageCalculatorOptions>());
-      RETURN_IF_ERROR(InitializeFromOptions());
+      MP_RETURN_IF_ERROR(InitializeFromOptions());
    }
    if (cc->Inputs().UsesTags() && cc->Inputs().HasTag("VIDEO_HEADER") &&
        !cc->Inputs().Tag("VIDEO_HEADER").IsEmpty()) {
@@ -548,7 +559,7 @@ ScaleImageCalculator::~ScaleImageCalculator() {}
  if (input_format_ == ImageFormat::YCBCR420P) {
    const YUVImage* yuv_image =
        &cc->Inputs().Get(input_data_id_).Get<YUVImage>();
-    RETURN_IF_ERROR(ValidateYUVImage(cc, *yuv_image));
+    MP_RETURN_IF_ERROR(ValidateYUVImage(cc, *yuv_image));

    if (output_format_ == ImageFormat::SRGB) {
      // TODO: For ease of implementation, YUVImage is converted to
@@ -596,7 +607,7 @@ ScaleImageCalculator::~ScaleImageCalculator() {}
    }
  } else {
    image_frame = &cc->Inputs().Get(input_data_id_).Get<ImageFrame>();
-    RETURN_IF_ERROR(ValidateImageFrame(cc, *image_frame));
+    MP_RETURN_IF_ERROR(ValidateImageFrame(cc, *image_frame));
  }

  std::unique_ptr<ImageFrame> cropped_image;
@@ -11,9 +11,10 @@ import "mediapipe/framework/formats/image_format.proto";
 // 2) Scale and convert the image to fit inside target_width x target_height
 //    using the specified scaling algorithm.  (maintaining the aspect
 //    ratio if preserve_aspect_ratio is true).
-// The output width and height will be divisible by 2. It is possible to output
-// width and height that are odd number when the output format is SRGB and not
-// perserving the aspect ratio. See scale_to_multiple_of_two option for details.
+// The output width and height will be divisible by 2, by default. It is
+// possible to output width and height that are odd numbers when the output
+// format is SRGB and the aspect ratio is left unpreserved. See
+// scale_to_multiple_of for details.
 message ScaleImageCalculatorOptions {
  extend CalculatorOptions {
    optional ScaleImageCalculatorOptions ext = 66237115;
@@ -23,7 +24,7 @@ message ScaleImageCalculatorOptions {
  // depending on the other options below.  If unset, use the same width
  // or height as the input.  If only one is set then determine the other
  // from the aspect ratio (after cropping).  The output width and height
-  // will be divisible by 2.
+  // will be divisible by 2, by default.
  optional int32 target_width = 1;
  optional int32 target_height = 2;

@@ -31,12 +32,14 @@ message ScaleImageCalculatorOptions {
  // fits inside the box represented by target_width and target_height.
  // Otherwise it is scaled to fit target_width and target_height
  // completely.  In any case, the aspect ratio that is preserved is
-  // that after cropping to the minimum/maximum aspect ratio.
+  // that after cropping to the minimum/maximum aspect ratio. Additionally, if
+  // true, the output width and height will be divisible by 2.
  optional bool preserve_aspect_ratio = 3 [default = true];

  // If ratio is positive, crop the image to this minimum and maximum
  // aspect ratio (preserving the center of the frame).  This is done
-  // before scaling.
+  // before scaling.  The string must contain "/", so to disable cropping,
+  // set both to "0/1".
  //   For example, for a min_aspect_ratio of "9/16" and max of "16/9" the
  //   following cropping will occur:
  //       1920x1080 (which is 16:9) is not cropped
@@ -94,11 +97,13 @@ message ScaleImageCalculatorOptions {
  // SRGB or YCBCR420P.
  optional ImageFormat.Format input_format = 12;

-  // If true, the output width and height will be divisible by 2. Otherwise it
-  // will use the exact specified output width and height, which is only
-  // supported when the output format is SRGB and preserve_aspect_ratio option
-  // is set to false.
-  optional bool scale_to_multiple_of_two = 13 [default = true];
+  // If set to 2, the target width and height will be rounded-down
+  // to the nearest even number. If set to any positive value other than 2,
+  // preserve_aspect_ratio must be false and the target width and height will be
+  // rounded-down to multiples of the given value. If set to any value less than
+  // 1, it will be treated like 1.
+  // NOTE: If set to an odd number, the output format must be SRGB.
+  optional int32 scale_to_multiple_of = 13 [default = 2];

  // If true, assume the input YUV is BT.709 (this is the HDTV standard, so most
  // content is likely using it). If false use the previous assumption of BT.601
@@ -88,17 +88,27 @@ double ParseRational(const std::string& rational) {
  return ::mediapipe::OkStatus();
 }

-::mediapipe::Status FindOutputDimensions(int input_width,                //
-                                         int input_height,               //
-                                         int target_width,               //
-                                         int target_height,              //
-                                         bool preserve_aspect_ratio,     //
-                                         bool scale_to_multiple_of_two,  //
+::mediapipe::Status FindOutputDimensions(int input_width,             //
+                                         int input_height,            //
+                                         int target_width,            //
+                                         int target_height,           //
+                                         bool preserve_aspect_ratio,  //
+                                         int scale_to_multiple_of,    //
                                         int* output_width,
                                         int* output_height) {
  CHECK(output_width);
  CHECK(output_height);

+  if (preserve_aspect_ratio) {
+    RET_CHECK(scale_to_multiple_of == 2)
+        << "FindOutputDimensions always outputs width and height that are "
+           "divisible by 2 when preserving aspect ratio. If you'd like to "
+           "set scale_to_multiple_of to something other than 2, please "
+           "set preserve_aspect_ratio to false.";
+  }
+
+  if (scale_to_multiple_of < 1) scale_to_multiple_of = 1;
+
  if (!preserve_aspect_ratio || (target_width <= 0 && target_height <= 0)) {
    if (target_width <= 0) {
      target_width = input_width;
@@ -106,13 +116,13 @@ double ParseRational(const std::string& rational) {
    if (target_height <= 0) {
      target_height = input_height;
    }
-    if (scale_to_multiple_of_two) {
-      *output_width = (target_width / 2) * 2;
-      *output_height = (target_height / 2) * 2;
-    } else {
-      *output_width = target_width;
-      *output_height = target_height;
-    }
+
+    target_width -= target_width % scale_to_multiple_of;
+    target_height -= target_height % scale_to_multiple_of;
+
+    *output_width = target_width;
+    *output_height = target_height;
+
    return ::mediapipe::OkStatus();
  }

@@ -35,17 +35,19 @@ namespace scale_image {
                                       int* col_start, int* row_start);

 // Given an input width and height, a target width and height, whether to
-// preserve the aspect ratio, and whether to round down to a multiple of 2,
-// determine the output width and height. If target_width or target_height is
-// non-positive, then they will be set to the input_width and input_height
-// respectively. The output_width and output_height will be reduced as necessary
-// to preserve_aspect_ratio and to scale_to_multipe_of_two if these options are
-// specified.
+// preserve the aspect ratio, and whether to round-down to the multiple of a
+// given number nearest to the targets, determine the output width and height.
+// If target_width or target_height is non-positive, then they will be set to
+// the input_width and input_height respectively. If scale_to_multiple_of is
+// less than 1, it will be treated like 1. The output_width and
+// output_height will be reduced as necessary to preserve_aspect_ratio if the
+// option is specified. If preserving the aspect ratio is desired, you must set
+// scale_to_multiple_of to 2.
 ::mediapipe::Status FindOutputDimensions(int input_width, int input_height,  //
                                         int target_width,
-                                         int target_height,              //
-                                         bool preserve_aspect_ratio,     //
-                                         bool scale_to_multiple_of_two,  //
+                                         int target_height,           //
+                                         bool preserve_aspect_ratio,  //
+                                         int scale_to_multiple_of,    //
                                         int* output_width, int* output_height);

 }  // namespace scale_image
@@ -28,8 +28,8 @@ TEST(ScaleImageUtilsTest, FindCropDimensions) {
  int col_start;
  int row_start;
  // No cropping because aspect ratios should be ignored.
-  MEDIAPIPE_ASSERT_OK(FindCropDimensions(50, 100, "0/1", "1/0", &crop_width,
-                                         &crop_height, &col_start, &row_start));
+  MP_ASSERT_OK(FindCropDimensions(50, 100, "0/1", "1/0", &crop_width,
+                                  &crop_height, &col_start, &row_start));
  EXPECT_EQ(50, crop_width);
  EXPECT_EQ(100, crop_height);
  EXPECT_EQ(0, row_start);
@@ -37,39 +37,38 @@ TEST(ScaleImageUtilsTest, FindCropDimensions) {

  // Tests proto examples.
  // 16:9 aspect ratio, should be unchanged.
-  MEDIAPIPE_ASSERT_OK(FindCropDimensions(1920, 1080, "9/16", "16/9",
-                                         &crop_width, &crop_height, &col_start,
-                                         &row_start));
+  MP_ASSERT_OK(FindCropDimensions(1920, 1080, "9/16", "16/9", &crop_width,
+                                  &crop_height, &col_start, &row_start));
  EXPECT_EQ(0, col_start);
  EXPECT_EQ(1920, crop_width);
  EXPECT_EQ(0, row_start);
  EXPECT_EQ(1080, crop_height);
  // 10:16 aspect ratio, should be unchanged.
-  MEDIAPIPE_ASSERT_OK(FindCropDimensions(640, 1024, "9/16", "16/9", &crop_width,
-                                         &crop_height, &col_start, &row_start));
+  MP_ASSERT_OK(FindCropDimensions(640, 1024, "9/16", "16/9", &crop_width,
+                                  &crop_height, &col_start, &row_start));
  EXPECT_EQ(0, col_start);
  EXPECT_EQ(640, crop_width);
  EXPECT_EQ(0, row_start);
  EXPECT_EQ(1024, crop_height);

  // 2:1 aspect ratio, width is cropped.
-  MEDIAPIPE_ASSERT_OK(FindCropDimensions(640, 320, "9/16", "16/9", &crop_width,
-                                         &crop_height, &col_start, &row_start));
+  MP_ASSERT_OK(FindCropDimensions(640, 320, "9/16", "16/9", &crop_width,
+                                  &crop_height, &col_start, &row_start));
  EXPECT_EQ(36, col_start);
  EXPECT_EQ(568, crop_width);
  EXPECT_EQ(0, row_start);
  EXPECT_EQ(320, crop_height);
  // 1:5 aspect ratio, height is cropped.
-  MEDIAPIPE_ASSERT_OK(FindCropDimensions(96, 480, "9/16", "16/9", &crop_width,
-                                         &crop_height, &col_start, &row_start));
+  MP_ASSERT_OK(FindCropDimensions(96, 480, "9/16", "16/9", &crop_width,
+                                  &crop_height, &col_start, &row_start));
  EXPECT_EQ(0, col_start);
  EXPECT_EQ(96, crop_width);
  EXPECT_EQ(155, row_start);
  EXPECT_EQ(170, crop_height);

  // Tests min = max, crops width.
-  MEDIAPIPE_ASSERT_OK(FindCropDimensions(200, 100, "1/1", "1/1", &crop_width,
-                                         &crop_height, &col_start, &row_start));
+  MP_ASSERT_OK(FindCropDimensions(200, 100, "1/1", "1/1", &crop_width,
+                                  &crop_height, &col_start, &row_start));
  EXPECT_EQ(50, col_start);
  EXPECT_EQ(100, crop_width);
  EXPECT_EQ(0, row_start);
@@ -80,49 +79,49 @@ TEST(ScaleImageUtilsTest, FindOutputDimensionsPreserveRatio) {
  int output_width;
  int output_height;
  // Not scale.
-  MEDIAPIPE_ASSERT_OK(FindOutputDimensions(200, 100, -1, -1, true, true,
-                                           &output_width, &output_height));
+  MP_ASSERT_OK(FindOutputDimensions(200, 100, -1, -1, true, 2, &output_width,
+                                    &output_height));
  EXPECT_EQ(200, output_width);
  EXPECT_EQ(100, output_height);
  // Not scale with odd input size.
-  MEDIAPIPE_ASSERT_OK(FindOutputDimensions(201, 101, -1, -1, false, false,
-                                           &output_width, &output_height));
+  MP_ASSERT_OK(FindOutputDimensions(201, 101, -1, -1, false, 1, &output_width,
+                                    &output_height));
  EXPECT_EQ(201, output_width);
  EXPECT_EQ(101, output_height);
  // Scale down by 1/2.
-  MEDIAPIPE_ASSERT_OK(FindOutputDimensions(200, 100, 100, -1, true, true,
-                                           &output_width, &output_height));
+  MP_ASSERT_OK(FindOutputDimensions(200, 100, 100, -1, true, 2, &output_width,
+                                    &output_height));
  EXPECT_EQ(100, output_width);
  EXPECT_EQ(50, output_height);
  // Scale up, doubling dimensions.
-  MEDIAPIPE_ASSERT_OK(FindOutputDimensions(200, 100, -1, 200, true, true,
-                                           &output_width, &output_height));
+  MP_ASSERT_OK(FindOutputDimensions(200, 100, -1, 200, true, 2, &output_width,
+                                    &output_height));
  EXPECT_EQ(400, output_width);
  EXPECT_EQ(200, output_height);
  // Fits a 2:1 image into a 150 x 150 box. Output dimensions are always
  // visible by 2.
-  MEDIAPIPE_ASSERT_OK(FindOutputDimensions(200, 100, 150, 150, true, true,
-                                           &output_width, &output_height));
+  MP_ASSERT_OK(FindOutputDimensions(200, 100, 150, 150, true, 2, &output_width,
+                                    &output_height));
  EXPECT_EQ(150, output_width);
  EXPECT_EQ(74, output_height);
  // Fits a 2:1 image into a 400 x 50 box.
-  MEDIAPIPE_ASSERT_OK(FindOutputDimensions(200, 100, 400, 50, true, true,
-                                           &output_width, &output_height));
+  MP_ASSERT_OK(FindOutputDimensions(200, 100, 400, 50, true, 2, &output_width,
+                                    &output_height));
  EXPECT_EQ(100, output_width);
  EXPECT_EQ(50, output_height);
  // Scale to multiple number with odd targe size.
-  MEDIAPIPE_ASSERT_OK(FindOutputDimensions(200, 100, 101, -1, true, true,
-                                           &output_width, &output_height));
+  MP_ASSERT_OK(FindOutputDimensions(200, 100, 101, -1, true, 2, &output_width,
+                                    &output_height));
  EXPECT_EQ(100, output_width);
  EXPECT_EQ(50, output_height);
  // Scale to multiple number with odd targe size.
-  MEDIAPIPE_ASSERT_OK(FindOutputDimensions(200, 100, 101, -1, true, false,
-                                           &output_width, &output_height));
+  MP_ASSERT_OK(FindOutputDimensions(200, 100, 101, -1, true, 2, &output_width,
+                                    &output_height));
  EXPECT_EQ(100, output_width);
  EXPECT_EQ(50, output_height);
  // Scale to odd size.
-  MEDIAPIPE_ASSERT_OK(FindOutputDimensions(200, 100, 151, 101, false, false,
-                                           &output_width, &output_height));
+  MP_ASSERT_OK(FindOutputDimensions(200, 100, 151, 101, false, 1, &output_width,
+                                    &output_height));
  EXPECT_EQ(151, output_width);
  EXPECT_EQ(101, output_height);
 }
@@ -132,22 +131,62 @@ TEST(ScaleImageUtilsTest, FindOutputDimensionsNoAspectRatio) {
  int output_width;
  int output_height;
  // Scale width only.
-  MEDIAPIPE_ASSERT_OK(FindOutputDimensions(200, 100, 100, -1, false, true,
-                                           &output_width, &output_height));
+  MP_ASSERT_OK(FindOutputDimensions(200, 100, 100, -1, false, 2, &output_width,
+                                    &output_height));
  EXPECT_EQ(100, output_width);
  EXPECT_EQ(100, output_height);
  // Scale height only.
-  MEDIAPIPE_ASSERT_OK(FindOutputDimensions(200, 100, -1, 200, false, true,
-                                           &output_width, &output_height));
+  MP_ASSERT_OK(FindOutputDimensions(200, 100, -1, 200, false, 2, &output_width,
+                                    &output_height));
  EXPECT_EQ(200, output_width);
  EXPECT_EQ(200, output_height);
  // Scale both dimensions.
-  MEDIAPIPE_ASSERT_OK(FindOutputDimensions(200, 100, 150, 200, false, true,
-                                           &output_width, &output_height));
+  MP_ASSERT_OK(FindOutputDimensions(200, 100, 150, 200, false, 2, &output_width,
+                                    &output_height));
  EXPECT_EQ(150, output_width);
  EXPECT_EQ(200, output_height);
 }

+// Tests scale_to_multiple_of.
+TEST(ScaleImageUtilsTest, FindOutputDimensionsDownScaleToMultipleOf) {
+  int output_width;
+  int output_height;
+  // Set no targets, downscale to a multiple of 8.
+  MP_ASSERT_OK(FindOutputDimensions(100, 100, -1, -1, false, 8, &output_width,
+                                    &output_height));
+  EXPECT_EQ(96, output_width);
+  EXPECT_EQ(96, output_height);
+  // Set width target, downscale to a multiple of 8.
+  MP_ASSERT_OK(FindOutputDimensions(200, 100, 100, -1, false, 8, &output_width,
+                                    &output_height));
+  EXPECT_EQ(96, output_width);
+  EXPECT_EQ(96, output_height);
+  // Set height target, downscale to a multiple of 8.
+  MP_ASSERT_OK(FindOutputDimensions(201, 101, -1, 201, false, 8, &output_width,
+                                    &output_height));
+  EXPECT_EQ(200, output_width);
+  EXPECT_EQ(200, output_height);
+  // Set both targets, downscale to a multiple of 8.
+  MP_ASSERT_OK(FindOutputDimensions(200, 100, 150, 200, false, 8, &output_width,
+                                    &output_height));
+  EXPECT_EQ(144, output_width);
+  EXPECT_EQ(200, output_height);
+  // Doesn't throw error if keep aspect is true and downscale multiple is 2.
+  MP_ASSERT_OK(FindOutputDimensions(200, 100, 400, 200, true, 2, &output_width,
+                                    &output_height));
+  EXPECT_EQ(400, output_width);
+  EXPECT_EQ(200, output_height);
+  // Throws error if keep aspect is true, but downscale multiple is not 2.
+  ASSERT_THAT(FindOutputDimensions(200, 100, 400, 200, true, 4, &output_width,
+                                   &output_height),
+              testing::Not(testing::status::IsOk()));
+  // Downscaling to multiple ignored if multiple is less than 2.
+  MP_ASSERT_OK(FindOutputDimensions(200, 100, 401, 201, false, 1, &output_width,
+                                    &output_height));
+  EXPECT_EQ(401, output_width);
+  EXPECT_EQ(201, output_height);
+}
+
 }  // namespace
 }  // namespace scale_image
 }  // namespace mediapipe
@@ -25,12 +25,11 @@
 #include "mediapipe/framework/port/status.h"
 #include "mediapipe/framework/port/vector.h"

-#if defined(__ANDROID__) || (defined(__APPLE__) && !TARGET_OS_OSX)
+#if !defined(MEDIAPIPE_DISABLE_GPU)
 #include "mediapipe/gpu/gl_calculator_helper.h"
 #include "mediapipe/gpu/gl_simple_shaders.h"
-#include "mediapipe/gpu/gpu_buffer.h"
 #include "mediapipe/gpu/shader_util.h"
-#endif  // __ANDROID__ or iOS
+#endif  //  !MEDIAPIPE_DISABLE_GPU

 namespace mediapipe {

@@ -107,16 +106,18 @@ class SetAlphaCalculator : public CalculatorBase {

  bool use_gpu_ = false;
  bool gpu_initialized_ = false;
-#if defined(__ANDROID__) || (defined(__APPLE__) && !TARGET_OS_OSX)
+#if !defined(MEDIAPIPE_DISABLE_GPU)
  mediapipe::GlCalculatorHelper gpu_helper_;
  GLuint program_ = 0;
-#endif  // __ANDROID__ or iOS
+#endif  //  !MEDIAPIPE_DISABLE_GPU
 };
 REGISTER_CALCULATOR(SetAlphaCalculator);

 ::mediapipe::Status SetAlphaCalculator::GetContract(CalculatorContract* cc) {
  CHECK_GE(cc->Inputs().NumEntries(), 1);

+  bool use_gpu = false;
+
  if (cc->Inputs().HasTag(kInputFrameTag) &&
      cc->Inputs().HasTag(kInputFrameTagGpu)) {
    return ::mediapipe::InternalError("Cannot have multiple input images.");
@@ -127,38 +128,43 @@ REGISTER_CALCULATOR(SetAlphaCalculator);
  }

  // Input image to add/edit alpha channel.
-#if defined(__ANDROID__) || (defined(__APPLE__) && !TARGET_OS_OSX)
+#if !defined(MEDIAPIPE_DISABLE_GPU)
  if (cc->Inputs().HasTag(kInputFrameTagGpu)) {
    cc->Inputs().Tag(kInputFrameTagGpu).Set<mediapipe::GpuBuffer>();
+    use_gpu |= true;
  }
-#endif  // __ANDROID__ or iOS
+#endif  //  !MEDIAPIPE_DISABLE_GPU
  if (cc->Inputs().HasTag(kInputFrameTag)) {
    cc->Inputs().Tag(kInputFrameTag).Set<ImageFrame>();
  }

  // Input alpha image mask (optional)
-#if defined(__ANDROID__) || (defined(__APPLE__) && !TARGET_OS_OSX)
+#if !defined(MEDIAPIPE_DISABLE_GPU)
  if (cc->Inputs().HasTag(kInputAlphaTagGpu)) {
    cc->Inputs().Tag(kInputAlphaTagGpu).Set<mediapipe::GpuBuffer>();
+    use_gpu |= true;
  }
-#endif  // __ANDROID__ or iOS
+#endif  //  !MEDIAPIPE_DISABLE_GPU
  if (cc->Inputs().HasTag(kInputAlphaTag)) {
    cc->Inputs().Tag(kInputAlphaTag).Set<ImageFrame>();
  }

  // RGBA output image.
-#if defined(__ANDROID__) || (defined(__APPLE__) && !TARGET_OS_OSX)
+#if !defined(MEDIAPIPE_DISABLE_GPU)
  if (cc->Outputs().HasTag(kOutputFrameTagGpu)) {
    cc->Outputs().Tag(kOutputFrameTagGpu).Set<mediapipe::GpuBuffer>();
+    use_gpu |= true;
  }
-#endif  // __ANDROID__ or iOS
+#endif  //  !MEDIAPIPE_DISABLE_GPU
  if (cc->Outputs().HasTag(kOutputFrameTag)) {
    cc->Outputs().Tag(kOutputFrameTag).Set<ImageFrame>();
  }

-#if defined(__ANDROID__) || (defined(__APPLE__) && !TARGET_OS_OSX)
-  RETURN_IF_ERROR(mediapipe::GlCalculatorHelper::UpdateContract(cc));
-#endif  // __ANDROID__ or iOS
+  if (use_gpu) {
+#if !defined(MEDIAPIPE_DISABLE_GPU)
+    MP_RETURN_IF_ERROR(mediapipe::GlCalculatorHelper::UpdateContract(cc));
+#endif  //  !MEDIAPIPE_DISABLE_GPU
+  }

  return ::mediapipe::OkStatus();
 }
@@ -170,11 +176,11 @@ REGISTER_CALCULATOR(SetAlphaCalculator);

  if (cc->Inputs().HasTag(kInputFrameTagGpu) &&
      cc->Outputs().HasTag(kOutputFrameTagGpu)) {
-#if defined(__ANDROID__) || (defined(__APPLE__) && !TARGET_OS_OSX)
+#if !defined(MEDIAPIPE_DISABLE_GPU)
    use_gpu_ = true;
 #else
-    RET_CHECK_FAIL() << "GPU processing is for Android and iOS only.";
-#endif  // __ANDROID__ or iOS
+    RET_CHECK_FAIL() << "GPU processing not enabled.";
+#endif  //  !MEDIAPIPE_DISABLE_GPU
  }

  // Get global value from options (-1 if not set).
@@ -187,41 +193,41 @@ REGISTER_CALCULATOR(SetAlphaCalculator);
    RET_CHECK_FAIL() << "Must use either image mask or options alpha value.";

  if (use_gpu_) {
-#if defined(__ANDROID__) || (defined(__APPLE__) && !TARGET_OS_OSX)
-    RETURN_IF_ERROR(gpu_helper_.Open(cc));
+#if !defined(MEDIAPIPE_DISABLE_GPU)
+    MP_RETURN_IF_ERROR(gpu_helper_.Open(cc));
 #endif
-  }
+  }  //  !MEDIAPIPE_DISABLE_GPU

  return ::mediapipe::OkStatus();
 }

 ::mediapipe::Status SetAlphaCalculator::Process(CalculatorContext* cc) {
  if (use_gpu_) {
-#if defined(__ANDROID__) || (defined(__APPLE__) && !TARGET_OS_OSX)
-    RETURN_IF_ERROR(
+#if !defined(MEDIAPIPE_DISABLE_GPU)
+    MP_RETURN_IF_ERROR(
        gpu_helper_.RunInGlContext([this, cc]() -> ::mediapipe::Status {
          if (!gpu_initialized_) {
-            RETURN_IF_ERROR(GlSetup(cc));
+            MP_RETURN_IF_ERROR(GlSetup(cc));
            gpu_initialized_ = true;
          }
-          RETURN_IF_ERROR(RenderGpu(cc));
+          MP_RETURN_IF_ERROR(RenderGpu(cc));
          return ::mediapipe::OkStatus();
        }));
-#endif  // __ANDROID__ or iOS
+#endif  //  !MEDIAPIPE_DISABLE_GPU
  } else {
-    RETURN_IF_ERROR(RenderCpu(cc));
+    MP_RETURN_IF_ERROR(RenderCpu(cc));
  }

  return ::mediapipe::OkStatus();
 }

 ::mediapipe::Status SetAlphaCalculator::Close(CalculatorContext* cc) {
-#if defined(__ANDROID__) || (defined(__APPLE__) && !TARGET_OS_OSX)
+#if !defined(MEDIAPIPE_DISABLE_GPU)
  gpu_helper_.RunInGlContext([this] {
    if (program_) glDeleteProgram(program_);
    program_ = 0;
  });
-#endif  // __ANDROID__ or iOS
+#endif  //  !MEDIAPIPE_DISABLE_GPU

  return ::mediapipe::OkStatus();
 }
@@ -295,7 +301,7 @@ REGISTER_CALCULATOR(SetAlphaCalculator);
  if (cc->Inputs().Tag(kInputFrameTagGpu).IsEmpty()) {
    return ::mediapipe::OkStatus();
  }
-#if defined(__ANDROID__) || (defined(__APPLE__) && !TARGET_OS_OSX)
+#if !defined(MEDIAPIPE_DISABLE_GPU)
  // Setup source texture.
  const auto& input_frame =
      cc->Inputs().Tag(kInputFrameTagGpu).Get<mediapipe::GpuBuffer>();
@@ -348,13 +354,13 @@ REGISTER_CALCULATOR(SetAlphaCalculator);
  // Cleanup
  input_texture.Release();
  output_texture.Release();
-#endif  // __ANDROID__ or iOS
+#endif  //  !MEDIAPIPE_DISABLE_GPU

  return ::mediapipe::OkStatus();
 }

 void SetAlphaCalculator::GlRender(CalculatorContext* cc) {
-#if defined(__ANDROID__) || (defined(__APPLE__) && !TARGET_OS_OSX)
+#if !defined(MEDIAPIPE_DISABLE_GPU)
  static const GLfloat square_vertices[] = {
      -1.0f, -1.0f,  // bottom left
      1.0f,  -1.0f,  // bottom right
@@ -403,11 +409,11 @@ void SetAlphaCalculator::GlRender(CalculatorContext* cc) {
  glDeleteVertexArrays(1, &vao);
  glDeleteBuffers(2, vbo);

-#endif  // __ANDROID__ or iOS
+#endif  //  !MEDIAPIPE_DISABLE_GPU
 }

 ::mediapipe::Status SetAlphaCalculator::GlSetup(CalculatorContext* cc) {
-#if defined(__ANDROID__) || (defined(__APPLE__) && !TARGET_OS_OSX)
+#if !defined(MEDIAPIPE_DISABLE_GPU)
  const GLint attr_location[NUM_ATTRIBUTES] = {
      ATTRIB_VERTEX,
      ATTRIB_TEXTURE_POSITION,
@@ -460,7 +466,7 @@ void SetAlphaCalculator::GlRender(CalculatorContext* cc) {
  glUniform1i(glGetUniformLocation(program_, "alpha_mask"), 2);
  glUniform1f(glGetUniformLocation(program_, "alpha_value"), alpha_value_);

-#endif  // __ANDROID__ or iOS
+#endif  //  !MEDIAPIPE_DISABLE_GPU

  return ::mediapipe::OkStatus();
 }
@@ -21,6 +21,7 @@ filegroup(
        "dino.jpg",
        "dino_quality_50.jpg",
        "dino_quality_80.jpg",
+        "front_camera_pixel2.jpg",
    ],
    visibility = ["//visibility:public"],
 )
--- a/Show More
+++ b/Show More
Author	SHA1	Message	Date
MediaPipe Teamandjqtang	4c68eb4a70	Project import generated by Copybara. GitOrigin-RevId: da3cb82c964457b1c719c915a48e545b980af64b	2020-04-06 21:28:19 -07:00
MediaPipe Teamandjqtang	a3d36eee32	Project import generated by Copybara. GitOrigin-RevId: 53a42bf7ad836321123cb7b6c80b0f2e13fbf83e	2020-04-06 19:14:13 -07:00
MediaPipe Teamandjqtang	1722d4b8a2	Project import generated by Copybara. GitOrigin-RevId: 43cd697ec87dcc5cab5051f27960bb77a057399d	2020-03-20 15:28:51 -07:00
MediaPipe Teamandjqtang	3b6d3c4058	Project import generated by Copybara. GitOrigin-RevId: 4419aaa472eeb91123d1f8576188166ee0e5ea69	2020-03-10 18:14:25 -07:00
MediaPipe Teamandjqtang	252a5713c7	Project import generated by Copybara. GitOrigin-RevId: 6f964e58d874e47fb6207aa97d060a4cd6428527	2020-03-02 10:35:07 -08:00
MediaPipe TeamandHadon Nash	de4fbc10e6	Project import generated by Copybara. GitOrigin-RevId: 852dfb05d450167899c0dd5ef7c45622a12e865b	2020-02-10 14:13:25 -08:00
MediaPipe Teamandjqtang	d144e564d8	Project import generated by Copybara. GitOrigin-RevId: df2c4ee5ecd342bd88f332389348615b47a0244c	2020-01-17 17:05:43 -08:00
MediaPipe Teamandchris	dd02df1dbe	Project import generated by Copybara. GitOrigin-RevId: b695dda274aa3ac3c7d054e150bd9eb5c1285b19	2020-01-17 15:49:22 -08:00
MediaPipe Teamandjqtang	66b377c825	Project import generated by Copybara. GitOrigin-RevId: 1dd19723270084e701a90f974e35754b3fe20265	2020-01-13 14:42:47 -08:00
MediaPipe Teamandjqtang	bf5185f122	Project import generated by Copybara. GitOrigin-RevId: 72933af9ce469acd89cbf41898dcc06c65df7c8a	2020-01-11 11:16:13 -08:00
MediaPipe Teamandjqtang	a2823541e6	Project import generated by Copybara. GitOrigin-RevId: 1237f560f10007d74f620349f9fe27b492f5faf6	2020-01-10 15:51:18 -08:00
MediaPipe TeamandHadon Nash	ae6be10afe	Project import generated by Copybara. GitOrigin-RevId: 0517756260533d374df93679965ca662d0ec6943	2020-01-10 13:13:24 -08:00
MediaPipe Teamandjqtang	38ee2603a7	Project import generated by Copybara. GitOrigin-RevId: 87e46800807001e01d686fd7bcc2533714556920	2019-12-09 13:11:22 -08:00
MediaPipe Teamandjqtang	86b3283b2f	Project import generated by Copybara. GitOrigin-RevId: 831b7eb6038549a3a5047e7a113d6a11956e2de9	2019-12-06 16:17:14 -08:00
MediaPipe Teamandjqtang	7d470a1335	Project import generated by Copybara. GitOrigin-RevId: 398d8577074c6e93041c01ed34bd6f27b2773c4f	2019-12-06 16:07:44 -08:00
MediaPipe Teamandmgyong	d16cc3be5b	Project import generated by Copybara. GitOrigin-RevId: d91373b4d4d10abef49cab410caa6aadf0875049	2019-12-06 15:57:20 -08:00
MediaPipe Teamandjqtang	137867d088	Project import generated by Copybara. GitOrigin-RevId: e3566e5029af25b0fc4b1071a49e49ae20aa5df6	2019-12-02 17:54:10 -08:00
MediaPipe Teamandmgyong	446d7cf6b6	Project import generated by Copybara. GitOrigin-RevId: b02a6442fa6234cd2c15fa19f09accd8767adbee	2019-11-21 14:48:32 -08:00
MediaPipe Teamandmgyong	90f72bd851	Project import generated by Copybara. GitOrigin-RevId: 5aa039c4a51ab7b4a1c58c17ad13af4c833e25e7	2019-11-21 14:35:46 -08:00
MediaPipe Teamandmgyong	4285aeddfc	Project import generated by Copybara. GitOrigin-RevId: 651ba7a75bb696877570a8a1b4244b34d59088f8	2019-11-21 14:24:17 -08:00
MediaPipe Teamandmgyong	37287925b0	Project import generated by Copybara. GitOrigin-RevId: ba1d851bc868c2f8037a6fa96ee90e4b8ab9bd40	2019-11-21 14:10:52 -08:00
MediaPipe Teamandmgyong	48bcbb115f	Project import generated by Copybara. GitOrigin-RevId: 50714fe28298d7b707eff7304547d89d6ec34a54	2019-11-21 13:20:47 -08:00
MediaPipe Teamandjqtang	9437483827	Project import generated by Copybara. GitOrigin-RevId: 5aca6b3f07b67e09988a901f50f595ca5f566e67	2019-11-15 13:10:50 -08:00
MediaPipe Teamandjqtang	d030c13931	Project import generated by Copybara. GitOrigin-RevId: dab808e56f90d1ad93e6014869f7fe4646b67fe0	2019-11-11 22:59:01 -08:00
MediaPipe Teamandjqtang	fce372d153	Project import generated by Copybara. GitOrigin-RevId: ac03a471f5b9df34de46dd684202e4365c5ceac3	2019-10-29 15:59:27 -07:00
MediaPipe Teamandjqtang	c6fea4c9d9	Project import generated by Copybara. GitOrigin-RevId: 1a0caa03bbf3673dbe772c8045b687c6b6821bcc	2019-10-25 14:50:09 -07:00
MediaPipe Teamandjqtang	259b48e082	Project import generated by Copybara. GitOrigin-RevId: b137378673f7d66d41bcd46e4fc3a0d9ef254894	2019-10-25 14:29:15 -07:00
MediaPipe Teamandjqtang	a2a63e3876	Project import generated by Copybara. GitOrigin-RevId: 796203faee20d7aae2876aac8ca5a1827dee4fe3	2019-09-30 11:26:36 -07:00
MediaPipe Teamandjqtang	412ab42d1f	Project import generated by Copybara. GitOrigin-RevId: f13909f37b252098f9a87d8b34e7fc855b8787b3	2019-09-18 15:06:31 -07:00
MediaPipe Teamandjqtang	cc1a02c54f	Project import generated by Copybara. GitOrigin-RevId: 03b457556bea85f6792ea9685cd4cea61e62f251	2019-09-16 15:23:51 -07:00
MediaPipe Teamandjqtang	b27c562e45	Project import generated by Copybara. GitOrigin-RevId: 5de341b25e069901e7773ed5067645ea6857f26c	2019-09-16 14:11:19 -07:00
MediaPipe Teamandjqtang	61bc4556af	Project import generated by Copybara. GitOrigin-RevId: 1138530ad1578c5d6615b3e3d041775c75d310c4	2019-09-11 14:29:38 -07:00
MediaPipe Teamandjqtang	423c21b454	Project import generated by Copybara. GitOrigin-RevId: c2597990d2200830529f823f969b7e48293ab787	2019-09-09 14:37:30 -07:00
MediaPipe Teamandjqtang	785d266e3f	Project import generated by Copybara. PiperOrigin-RevId: 267460010	2019-09-05 15:47:36 -07:00
MediaPipe Teamandjqtang	59a398924f	Project import generated by Copybara. PiperOrigin-RevId: 267400397	2019-09-05 10:31:35 -07:00
MediaPipe Teamandjqtang	dc9216dc59	Project import generated by Copybara. PiperOrigin-RevId: 267280553	2019-09-04 19:11:29 -07:00
MediaPipe Teamandjqtang	af67642055	Project import generated by Copybara. PiperOrigin-RevId: 267274408	2019-09-04 19:00:29 -07:00
MediaPipe Teamandjqtang	731d2b9536	Project import generated by Copybara. PiperOrigin-RevId: 264239673	2019-08-19 14:24:11 -07:00
MediaPipe Teamandjqtang	b83cfcc9b5	Project import generated by Copybara. PiperOrigin-RevId: 264195411	2019-08-19 11:09:50 -07:00
MediaPipe Teamandchuoling	9d45360bc9	Project import generated by Copybara. PiperOrigin-RevId: 264188826	2019-08-19 10:53:24 -07:00
MediaPipe TeamandCamillo Lugaresi	f5df228d9b	Project import generated by Copybara. PiperOrigin-RevId: 264105834	2019-08-19 08:50:18 +00:00