fix(mobile): properly pause and resume other audio during recording

js/mobile/src/features/compose/AudioRecordingOverlay.tsx

@@ -3,11 +3,14 @@ import { Pressable, StyleSheet, Text, View } from "react-native";
 import { Mic } from "lucide-react-native";
 import {
   RecordingPresets,
-  setAudioModeAsync,
   useAudioRecorder,
   useAudioRecorderState,
 } from "expo-audio";
 import { logError } from "@/lib/errors";
+import {
+  acquireRecordingAudioSession,
+  releaseRecordingAudioSession,
+} from "@/lib/recording-audio-session";
 
 const MAX_DURATION_S = 60;
 
@@ -28,10 +31,7 @@ export function AudioRecordingOverlay({
     let active = true;
     (async () => {
       try {
-        await setAudioModeAsync({
-          allowsRecording: true,
-          playsInSilentMode: true,
-        });
+        await acquireRecordingAudioSession();
         await recorder.prepareToRecordAsync();
         if (!active) return;
         recorder.record();
@@ -47,10 +47,9 @@ export function AudioRecordingOverlay({
         finalizedRef.current = true;
         recorder.stop().catch(() => {});
       }
-      void setAudioModeAsync({
-        allowsRecording: false,
-        playsInSilentMode: true,
-      }).catch((err) => logError(err, { scope: "compose.audio.exit" }));
+      void releaseRecordingAudioSession().catch((err) =>
+        logError(err, { scope: "compose.audio.exit" }),
+      );
     };
     // eslint-disable-next-line react-hooks/exhaustive-deps
   }, []);

js/mobile/src/features/compose/VideoRecordingOverlay.tsx

@@ -2,6 +2,10 @@ import { useEffect, useRef, useState } from "react";
 import { Platform, Pressable, StyleSheet, Text, View } from "react-native";
 import { CameraView } from "expo-camera";
 import { logError } from "@/lib/errors";
+import {
+  acquireRecordingAudioSession,
+  releaseRecordingAudioSession,
+} from "@/lib/recording-audio-session";
 
 const MAX_DURATION_S = 60;
 const VIDEO_BITRATE_BPS = 1_200_000;
@@ -25,6 +29,9 @@ export function VideoRecordingOverlay({
   useEffect(() => {
     return () => {
       cancelledRef.current = true;
+      void releaseRecordingAudioSession().catch((err) =>
+        logError(err, { scope: "compose.video.exit" }),
+      );
     };
   }, []);
 
@@ -32,6 +39,14 @@ export function VideoRecordingOverlay({
     const cam = cameraRef.current;
     if (!cam || recording || !cameraReady) return;
 
+    try {
+      await acquireRecordingAudioSession();
+    } catch (err) {
+      logError(err, { scope: "compose.video.audioSession" });
+      onCancel();
+      return;
+    }
+
     setRecording(true);
     startedAtRef.current = Date.now();
 
@@ -46,6 +61,10 @@ export function VideoRecordingOverlay({
       logError(err, { scope: "compose.video.recordAsync" });
       onCancel();
       return;
+    } finally {
+      void releaseRecordingAudioSession().catch((err) =>
+        logError(err, { scope: "compose.video.release" }),
+      );
     }
     if (cancelledRef.current) return;
 

js/mobile/src/lib/recording-audio-session.ts

@@ -0,0 +1,24 @@
+import { setAudioModeAsync, setIsAudioActiveAsync } from "expo-audio";
+
+// Around camera/mic recording we switch the iOS audio session to playAndRecord
+// with `doNotMix`, which cleanly interrupts other apps' audio (Spotify, Apple
+// Music, podcasts). On release we restore a mixable mode and then *deactivate*
+// the session — the deactivation is what passes notifyOthersOnDeactivation to
+// AVAudioSession, which is the signal that lets the previously-playing app
+// auto-resume. Just changing the category is not enough.
+export async function acquireRecordingAudioSession() {
+  await setAudioModeAsync({
+    allowsRecording: true,
+    playsInSilentMode: true,
+    interruptionMode: "doNotMix",
+  });
+}
+
+export async function releaseRecordingAudioSession() {
+  await setAudioModeAsync({
+    allowsRecording: false,
+    playsInSilentMode: true,
+    interruptionMode: "mixWithOthers",
+  });
+  await setIsAudioActiveAsync(false);
+}