Access finalAudioSink from playback thread

The finalAudioSink was accessed from the main thread but it should only
be accessed from the playback thread.

PiperOrigin-RevId: 743548450

libraries/transformer/src/main/java/androidx/media3/transformer/CompositionPlayer.java

@@ -336,7 +336,6 @@ public final class CompositionPlayer extends SimpleBasePlayer
   private LivePositionSupplier positionSupplier;
   private LivePositionSupplier bufferedPositionSupplier;
   private LivePositionSupplier totalBufferedDurationSupplier;
-  private boolean isSeeking;
 
   // "this" reference for position suppliers.
   @SuppressWarnings("initialization:methodref.receiver.bound.invalid")
@@ -506,9 +505,9 @@ public final class CompositionPlayer extends SimpleBasePlayer
     playWhenReadyChangeReason = PLAY_WHEN_READY_CHANGE_REASON_USER_REQUEST;
     if (playbackState == STATE_READY) {
       if (playWhenReady) {
-        finalAudioSink.play();
+        checkStateNotNull(compositionPlayerInternal).startRendering();
       } else {
-        finalAudioSink.pause();
+        checkStateNotNull(compositionPlayerInternal).stopRendering();
       }
       for (int i = 0; i < players.size(); i++) {
         players.get(i).setPlayWhenReady(playWhenReady);
@@ -587,7 +586,9 @@ public final class CompositionPlayer extends SimpleBasePlayer
   @Override
   protected ListenableFuture<?> handleSetVolume(float volume) {
     this.volume = Util.constrainValue(volume, /* min= */ 0.0f, /* max= */ 1.0f);
-    finalAudioSink.setVolume(this.volume);
+    if (compositionPlayerInternal != null) {
+      compositionPlayerInternal.setVolume(this.volume);
+    }
     return Futures.immediateVoidFuture();
   }
 
@@ -597,7 +598,6 @@ public final class CompositionPlayer extends SimpleBasePlayer
     resetLivePositionSuppliers();
     CompositionPlayerInternal compositionPlayerInternal =
         checkStateNotNull(this.compositionPlayerInternal);
-    isSeeking = true;
     compositionPlayerInternal.startSeek(positionMs);
     for (int i = 0; i < players.size(); i++) {
       players.get(i).seekTo(positionMs);
@@ -683,22 +683,17 @@ public final class CompositionPlayer extends SimpleBasePlayer
         for (int i = 0; i < players.size(); i++) {
           players.get(i).setPlayWhenReady(false);
         }
-        if (!isSeeking) {
+        checkStateNotNull(compositionPlayerInternal).stopRendering();
-          // The finalAudioSink cannot be paused more than once. The audio pipeline pauses it during
-          // a seek, so don't pause here when seeking.
-          finalAudioSink.pause();
-        }
       }
     } else if (endedCount == players.size()) {
       playbackState = STATE_ENDED;
     } else {
       playbackState = STATE_READY;
-      isSeeking = false;
       if (oldPlaybackState != STATE_READY && playWhenReady) {
         for (int i = 0; i < players.size(); i++) {
           players.get(i).setPlayWhenReady(true);
         }
-        finalAudioSink.play();
+        checkStateNotNull(compositionPlayerInternal).startRendering();
       }
     }
   }
@@ -799,6 +794,7 @@ public final class CompositionPlayer extends SimpleBasePlayer
             playbackVideoGraphWrapper,
             /* listener= */ this,
             compositionInternalListenerHandler);
+    compositionPlayerInternal.setVolume(volume);
   }
 
   private void setPrimaryPlayerSequence(ExoPlayer player, EditedMediaItemSequence sequence) {

libraries/transformer/src/main/java/androidx/media3/transformer/CompositionPlayerInternal.java

@@ -47,11 +47,14 @@ import androidx.media3.exoplayer.video.PlaybackVideoGraphWrapper;
   }
 
   private static final String TAG = "CompPlayerInternal";
-  private static final int MSG_SET_OUTPUT_SURFACE_INFO = 1;
+  private static final int MSG_START_RENDERING = 1;
-  private static final int MSG_CLEAR_OUTPUT_SURFACE = 2;
+  private static final int MSG_STOP_RENDERING = 2;
-  private static final int MSG_START_SEEK = 3;
+  private static final int MSG_SET_VOLUME = 3;
-  private static final int MSG_END_SEEK = 4;
+  private static final int MSG_SET_OUTPUT_SURFACE_INFO = 4;
-  private static final int MSG_RELEASE = 5;
+  private static final int MSG_CLEAR_OUTPUT_SURFACE = 5;
+  private static final int MSG_START_SEEK = 6;
+  private static final int MSG_END_SEEK = 7;
+  private static final int MSG_RELEASE = 8;
 
   private final Clock clock;
   private final HandlerWrapper handler;
@@ -94,6 +97,18 @@ import androidx.media3.exoplayer.video.PlaybackVideoGraphWrapper;
 
   // Public methods
 
+  public void startRendering() {
+    handler.sendEmptyMessage(MSG_START_RENDERING);
+  }
+
+  public void stopRendering() {
+    handler.sendEmptyMessage(MSG_STOP_RENDERING);
+  }
+
+  public void setVolume(float volume) {
+    handler.obtainMessage(MSG_SET_VOLUME, volume).sendToTarget();
+  }
+
   /** Sets the output surface information on the video pipeline. */
   public void setOutputSurfaceInfo(Surface surface, Size size) {
     handler
@@ -103,7 +118,7 @@ import androidx.media3.exoplayer.video.PlaybackVideoGraphWrapper;
 
   /** Clears the output surface from the video pipeline. */
   public void clearOutputSurface() {
-    handler.obtainMessage(MSG_CLEAR_OUTPUT_SURFACE).sendToTarget();
+    handler.sendEmptyMessage(MSG_CLEAR_OUTPUT_SURFACE);
   }
 
   public void startSeek(long positionMs) {
@@ -111,7 +126,7 @@ import androidx.media3.exoplayer.video.PlaybackVideoGraphWrapper;
   }
 
   public void endSeek() {
-    handler.obtainMessage(MSG_END_SEEK).sendToTarget();
+    handler.sendEmptyMessage(MSG_END_SEEK);
   }
 
   /**
@@ -139,6 +154,15 @@ import androidx.media3.exoplayer.video.PlaybackVideoGraphWrapper;
   public boolean handleMessage(Message message) {
     try {
       switch (message.what) {
+        case MSG_START_RENDERING:
+          playbackAudioGraphWrapper.startRendering();
+          break;
+        case MSG_STOP_RENDERING:
+          playbackAudioGraphWrapper.stopRendering();
+          break;
+        case MSG_SET_VOLUME:
+          playbackAudioGraphWrapper.setVolume(/* volume= */ (float) message.obj);
+          break;
         case MSG_SET_OUTPUT_SURFACE_INFO:
           setOutputSurfaceInfoOnInternalThread(
               /* outputSurfaceInfo= */ (OutputSurfaceInfo) message.obj);

libraries/transformer/src/main/java/androidx/media3/transformer/PlaybackAudioGraphWrapper.java

@@ -47,6 +47,7 @@ import java.util.Objects;
   private AudioFormat outputAudioFormat;
   private long outputFramesWritten;
   private long seekPositionUs;
+  private boolean isRenderingStarted;
 
   /**
    * Creates an instance.
@@ -135,6 +136,24 @@ import java.util.Objects;
         + sampleCountToDurationUs(outputFramesWritten, outputAudioFormat.sampleRate);
   }
 
+  public void startRendering() {
+    finalAudioSink.play();
+    isRenderingStarted = true;
+  }
+
+  public void stopRendering() {
+    if (!isRenderingStarted) {
+      // The finalAudioSink cannot be paused more than once.
+      return;
+    }
+    finalAudioSink.pause();
+    isRenderingStarted = false;
+  }
+
+  public void setVolume(float volume) {
+    finalAudioSink.setVolume(volume);
+  }
+
   /**
    * Handles the steps that need to be executed for a seek before seeking the upstream players.
    *
@@ -144,7 +163,7 @@ import java.util.Objects;
     if (positionUs == C.TIME_UNSET) {
       positionUs = 0;
     }
-    finalAudioSink.pause();
+    stopRendering();
     audioGraph.blockInput();
     audioGraph.setPendingStartTimeUs(positionUs);
     audioGraph.flush();