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mediapipe/mediapipe/tasks/python/metadata/metadata_writers/writer_utils.py
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Python

# Copyright 2022 The MediaPipe Authors. All Rights Reserved.
#
# 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.
# ==============================================================================
"""Helper methods for writing metadata into TFLite models."""
from typing import Dict, List
import zipfile
from mediapipe.tasks.metadata import schema_py_generated as _schema_fb
def get_input_tensor_names(model_buffer: bytearray) -> List[str]:
"""Gets a list of the input tensor names."""
subgraph = get_subgraph(model_buffer)
tensor_names = []
for i in range(subgraph.InputsLength()):
index = subgraph.Inputs(i)
tensor_names.append(subgraph.Tensors(index).Name().decode("utf-8"))
return tensor_names
def get_output_tensor_names(model_buffer: bytearray) -> List[str]:
"""Gets a list of the output tensor names."""
subgraph = get_subgraph(model_buffer)
tensor_names = []
for i in range(subgraph.OutputsLength()):
index = subgraph.Outputs(i)
tensor_names.append(subgraph.Tensors(index).Name().decode("utf-8"))
return tensor_names
def get_input_tensor_types(
model_buffer: bytearray) -> List[_schema_fb.TensorType]:
"""Gets a list of the input tensor types."""
subgraph = get_subgraph(model_buffer)
tensor_types = []
for i in range(subgraph.InputsLength()):
index = subgraph.Inputs(i)
tensor_types.append(subgraph.Tensors(index).Type())
return tensor_types
def get_output_tensor_types(
model_buffer: bytearray) -> List[_schema_fb.TensorType]:
"""Gets a list of the output tensor types."""
subgraph = get_subgraph(model_buffer)
tensor_types = []
for i in range(subgraph.OutputsLength()):
index = subgraph.Outputs(i)
tensor_types.append(subgraph.Tensors(index).Type())
return tensor_types
def get_subgraph(model_buffer: bytearray) -> _schema_fb.SubGraph:
"""Gets the subgraph of the model.
TFLite does not support multi-subgraph. A model should have exactly one
subgraph.
Args:
model_buffer: valid buffer of the model file.
Returns:
The subgraph of the model.
Raises:
ValueError: if the model has more than one subgraph or has no subgraph.
"""
model = _schema_fb.Model.GetRootAsModel(model_buffer, 0)
# Use the first subgraph as default. TFLite Interpreter doesn't support
# multiple subgraphs yet, but models with mini-benchmark may have multiple
# subgraphs for acceleration evaluation purpose.
return model.Subgraphs(0)
def create_model_asset_bundle(input_models: Dict[str, bytes],
output_path: str) -> None:
"""Creates the model asset bundle.
Args:
input_models: A dict of input models with key as the model file name and
value as the model content.
output_path: The output file path to save the model asset bundle.
"""
if not input_models or len(input_models) < 2:
raise ValueError("Needs at least two input models for model asset bundle.")
with zipfile.ZipFile(output_path, mode="w") as zf:
for file_name, file_buffer in input_models.items():
zf.writestr(file_name, file_buffer)