Expose AudioOffload track state.

Adds a new event to AudioOffloadListener to get the offload state of the track, which indicates when software decoding is taking place.

PiperOrigin-RevId: 465264362

RELEASENOTES.md

@@ -11,6 +11,10 @@
         ([#10057](https://github.com/google/ExoPlayer/issues/10057)).
     *   Limit parallel download removals to 1 to avoid excessive thread creation
         ([#10458](https://github.com/google/ExoPlayer/issues/10458)).
+*   Audio:
+    *   Adds AudioOffloadListener.onExperimentalOffloadedPlayback for the
+        AudioTrack offload state.
+        ([#134](https://github.com/androidx/media/issues/134)).
 *   Metadata:
     *   `MetadataRenderer` can now be configured to render metadata as soon as
         they are available. Create an instance with

libraries/exoplayer/src/main/java/androidx/media3/exoplayer/ExoPlayer.java

@@ -435,6 +435,16 @@ public interface ExoPlayer extends Player {
      * <p>This method is experimental, and will be renamed or removed in a future release.
      */
     default void onExperimentalSleepingForOffloadChanged(boolean sleepingForOffload) {}
+
+    /**
+     * Called when the value of {@link AudioTrack#isOffloadedPlayback} changes.
+     *
+     * <p>This should not be generally required to be acted upon. But when offload is critical for
+     * efficiency, or audio features (gapless, playback speed), this will let the app know.
+     *
+     * <p>This method is experimental, and will be renamed or removed in a future release.
+     */
+    default void onExperimentalOffloadedPlayback(boolean offloadedPlayback) {}
   }
 
   /**

libraries/exoplayer/src/main/java/androidx/media3/exoplayer/audio/DefaultAudioSink.java

@@ -50,6 +50,7 @@ import androidx.media3.common.util.ConditionVariable;
 import androidx.media3.common.util.Log;
 import androidx.media3.common.util.UnstableApi;
 import androidx.media3.common.util.Util;
+import androidx.media3.exoplayer.ExoPlayer.AudioOffloadListener;
 import androidx.media3.exoplayer.analytics.PlayerId;
 import androidx.media3.exoplayer.audio.AudioProcessor.UnhandledAudioFormatException;
 import androidx.media3.extractor.AacUtil;
@@ -274,6 +275,7 @@ public final class DefaultAudioSink implements AudioSink {
     private boolean enableAudioTrackPlaybackParams;
     private int offloadMode;
     AudioTrackBufferSizeProvider audioTrackBufferSizeProvider;
+    @Nullable AudioOffloadListener audioOffloadListener;
 
     /** Creates a new builder. */
     public Builder() {
@@ -379,6 +381,19 @@ public final class DefaultAudioSink implements AudioSink {
       return this;
     }
 
+    /**
+     * Sets an optional {@link AudioOffloadListener} to receive events relevant to offloaded
+     * playback.
+     *
+     * <p>The default value is null.
+     */
+    @CanIgnoreReturnValue
+    public Builder setExperimentalAudioOffloadListener(
+        @Nullable AudioOffloadListener audioOffloadListener) {
+      this.audioOffloadListener = audioOffloadListener;
+      return this;
+    }
+
     /** Builds the {@link DefaultAudioSink}. Must only be called once per Builder instance. */
     public DefaultAudioSink build() {
       if (audioProcessorChain == null) {
@@ -509,6 +524,7 @@ public final class DefaultAudioSink implements AudioSink {
       initializationExceptionPendingExceptionHolder;
   private final PendingExceptionHolder<WriteException> writeExceptionPendingExceptionHolder;
   private final AudioTrackBufferSizeProvider audioTrackBufferSizeProvider;
+  @Nullable private final AudioOffloadListener audioOffloadListener;
 
   @Nullable private PlayerId playerId;
   @Nullable private Listener listener;
@@ -669,6 +685,7 @@ public final class DefaultAudioSink implements AudioSink {
         new PendingExceptionHolder<>(AUDIO_TRACK_RETRY_DURATION_MS);
     writeExceptionPendingExceptionHolder =
         new PendingExceptionHolder<>(AUDIO_TRACK_RETRY_DURATION_MS);
+    audioOffloadListener = builder.audioOffloadListener;
   }
 
   // AudioSink implementation.
@@ -1096,7 +1113,12 @@ public final class DefaultAudioSink implements AudioSink {
 
   private AudioTrack buildAudioTrack(Configuration configuration) throws InitializationException {
     try {
-      return configuration.buildAudioTrack(tunneling, audioAttributes, audioSessionId);
+      AudioTrack audioTrack =
+          configuration.buildAudioTrack(tunneling, audioAttributes, audioSessionId);
+      if (audioOffloadListener != null) {
+        audioOffloadListener.onExperimentalOffloadedPlayback(isOffloadedPlayback(audioTrack));
+      }
+      return audioTrack;
     } catch (InitializationException e) {
       if (listener != null) {
         listener.onAudioSinkError(e);