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
(cherry picked from commit fe2b8465)

library/core/src/main/java/com/google/android/exoplayer2/ExoPlayer.java

@@ -423,6 +423,16 @@ public interface ExoPlayer extends Player {
      * <p>This method is experimental, and will be renamed or removed in a future release.
      * <p>This method is experimental, and will be renamed or removed in a future release.
      */
      */
     default void onExperimentalSleepingForOffloadChanged(boolean sleepingForOffload) {}
     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) {}
   }
   }
 
 
   /**
   /**

library/core/src/main/java/com/google/android/exoplayer2/audio/DefaultAudioSink.java

@@ -39,6 +39,7 @@ import androidx.annotation.IntDef;
 import androidx.annotation.Nullable;
 import androidx.annotation.Nullable;
 import androidx.annotation.RequiresApi;
 import androidx.annotation.RequiresApi;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.C;
+import com.google.android.exoplayer2.ExoPlayer.AudioOffloadListener;
 import com.google.android.exoplayer2.Format;
 import com.google.android.exoplayer2.Format;
 import com.google.android.exoplayer2.PlaybackParameters;
 import com.google.android.exoplayer2.PlaybackParameters;
 import com.google.android.exoplayer2.analytics.PlayerId;
 import com.google.android.exoplayer2.analytics.PlayerId;
@@ -265,6 +266,7 @@ public final class DefaultAudioSink implements AudioSink {
     private boolean enableAudioTrackPlaybackParams;
     private boolean enableAudioTrackPlaybackParams;
     private int offloadMode;
     private int offloadMode;
     AudioTrackBufferSizeProvider audioTrackBufferSizeProvider;
     AudioTrackBufferSizeProvider audioTrackBufferSizeProvider;
+    @Nullable AudioOffloadListener audioOffloadListener;
 
 
     /** Creates a new builder. */
     /** Creates a new builder. */
     public Builder() {
     public Builder() {
@@ -370,6 +372,19 @@ public final class DefaultAudioSink implements AudioSink {
       return this;
       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. */
     /** Builds the {@link DefaultAudioSink}. Must only be called once per Builder instance. */
     public DefaultAudioSink build() {
     public DefaultAudioSink build() {
       if (audioProcessorChain == null) {
       if (audioProcessorChain == null) {
@@ -500,6 +515,7 @@ public final class DefaultAudioSink implements AudioSink {
       initializationExceptionPendingExceptionHolder;
       initializationExceptionPendingExceptionHolder;
   private final PendingExceptionHolder<WriteException> writeExceptionPendingExceptionHolder;
   private final PendingExceptionHolder<WriteException> writeExceptionPendingExceptionHolder;
   private final AudioTrackBufferSizeProvider audioTrackBufferSizeProvider;
   private final AudioTrackBufferSizeProvider audioTrackBufferSizeProvider;
+  @Nullable private final AudioOffloadListener audioOffloadListener;
 
 
   @Nullable private PlayerId playerId;
   @Nullable private PlayerId playerId;
   @Nullable private Listener listener;
   @Nullable private Listener listener;
@@ -660,6 +676,7 @@ public final class DefaultAudioSink implements AudioSink {
         new PendingExceptionHolder<>(AUDIO_TRACK_RETRY_DURATION_MS);
         new PendingExceptionHolder<>(AUDIO_TRACK_RETRY_DURATION_MS);
     writeExceptionPendingExceptionHolder =
     writeExceptionPendingExceptionHolder =
         new PendingExceptionHolder<>(AUDIO_TRACK_RETRY_DURATION_MS);
         new PendingExceptionHolder<>(AUDIO_TRACK_RETRY_DURATION_MS);
+    audioOffloadListener = builder.audioOffloadListener;
   }
   }
 
 
   // AudioSink implementation.
   // AudioSink implementation.
@@ -1087,7 +1104,12 @@ public final class DefaultAudioSink implements AudioSink {
 
 
   private AudioTrack buildAudioTrack(Configuration configuration) throws InitializationException {
   private AudioTrack buildAudioTrack(Configuration configuration) throws InitializationException {
     try {
     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) {
     } catch (InitializationException e) {
       if (listener != null) {
       if (listener != null) {
         listener.onAudioSinkError(e);
         listener.onAudioSinkError(e);