Start and stop video rendering from CompositionPlayer

Before, we were starting and stopping video rendering when the
renderers were started/stopped. This doesn't work for multi-video
sequences though because we shouldn't stop and start rendering at every
MediaItem transition in any of the input sequences.

PiperOrigin-RevId: 750206410

libraries/exoplayer/src/main/java/androidx/media3/exoplayer/video/MediaCodecVideoRenderer.java

@@ -983,6 +983,7 @@ public class MediaCodecVideoRenderer extends MediaCodecRenderer
       Context context, VideoFrameReleaseControl videoFrameReleaseControl) {
     // TODO: b/391109644 - Add a more explicit API to enable replaying.
     return new PlaybackVideoGraphWrapper.Builder(context, videoFrameReleaseControl)
+        .setEnablePlaylistMode(true)
         .setClock(getClock())
         .build();
   }

libraries/exoplayer/src/main/java/androidx/media3/exoplayer/video/PlaybackVideoGraphWrapper.java

@@ -115,6 +115,7 @@ public final class PlaybackVideoGraphWrapper implements VideoSinkProvider, Video
     private VideoGraph.@MonotonicNonNull Factory videoGraphFactory;
     private List<Effect> compositionEffects;
     private VideoCompositorSettings compositorSettings;
+    private boolean enablePlaylistMode;
     private Clock clock;
     private boolean requestOpenGlToneMapping;
     private boolean built;
@@ -185,6 +186,36 @@ public final class PlaybackVideoGraphWrapper implements VideoSinkProvider, Video
       return this;
     }
 
+    /**
+     * Sets whether to enable playlist mode.
+     *
+     * <p>The default value is {@code false}.
+     *
+     * <p>This should only be set to {@code true} if there is a single {@linkplain
+     * PlaybackVideoGraphWrapper#getSink(int) input sink}.
+     *
+     * <p>If {@code true}, the {@link VideoGraph} output is considered as a playlist of clips. In
+     * this case, {@link PlaybackVideoGraphWrapper#startRendering()} and {@link
+     * PlaybackVideoGraphWrapper#stopRendering()} are called internally, when the corresponding
+     * methods are caller on the sink.
+     *
+     * <p>If {@code false}, the {@link VideoGraph} output is considered as a single clip. In this
+     * case, the caller is responsible for calling {@link
+     * PlaybackVideoGraphWrapper#startRendering()} and {@link
+     * PlaybackVideoGraphWrapper#stopRendering()}.
+     *
+     * @param enablePlaylistMode Whether to enable playlist mode.
+     * @return This builder, for convenience.
+     */
+    @CanIgnoreReturnValue
+    public Builder setEnablePlaylistMode(boolean enablePlaylistMode) {
+      // This is set to true for ExoPlayer.setVideoEffects(). It's always false in
+      // CompositionPlayer, even if the Composition has a single sequence, because CompositionPlayer
+      // shouldn't behave differently for single and multi-sequence.
+      this.enablePlaylistMode = enablePlaylistMode;
+      return this;
+    }
+
     /**
      * Sets the {@link Clock} that will be used.
      *
@@ -271,6 +302,7 @@ public final class PlaybackVideoGraphWrapper implements VideoSinkProvider, Video
   private final SparseArray<InputVideoSink> inputVideoSinks;
   private final List<Effect> compositionEffects;
   private final VideoCompositorSettings compositorSettings;
+  private final boolean enablePlaylistMode;
   private final VideoSink defaultVideoSink;
   private final VideoSink.VideoFrameHandler videoFrameHandler;
   private final Clock clock;
@@ -321,6 +353,7 @@ public final class PlaybackVideoGraphWrapper implements VideoSinkProvider, Video
     inputVideoSinks = new SparseArray<>();
     compositionEffects = builder.compositionEffects;
     compositorSettings = builder.compositorSettings;
+    enablePlaylistMode = builder.enablePlaylistMode;
     clock = builder.clock;
     defaultVideoSink = new DefaultVideoSink(builder.videoFrameReleaseControl, clock);
     videoFrameHandler =
@@ -363,6 +396,16 @@ public final class PlaybackVideoGraphWrapper implements VideoSinkProvider, Video
     listeners.remove(listener);
   }
 
+  /** Starts rendering to the output surface. */
+  public void startRendering() {
+    defaultVideoSink.startRendering();
+  }
+
+  /** Stops rendering to the output surface. */
+  public void stopRendering() {
+    defaultVideoSink.stopRendering();
+  }
+
   // VideoSinkProvider methods
 
   @Override
@@ -704,12 +747,16 @@ public final class PlaybackVideoGraphWrapper implements VideoSinkProvider, Video
 
     @Override
     public void startRendering() {
-      defaultVideoSink.startRendering();
+      if (enablePlaylistMode) {
+        PlaybackVideoGraphWrapper.this.startRendering();
+      }
     }
 
     @Override
     public void stopRendering() {
-      defaultVideoSink.stopRendering();
+      if (enablePlaylistMode) {
+        PlaybackVideoGraphWrapper.this.stopRendering();
+      }
     }
 
     @Override

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

@@ -743,6 +743,7 @@ public final class CompositionPlayer extends SimpleBasePlayer
       }
     } else if (endedCount == players.size()) {
       playbackState = STATE_ENDED;
+      checkStateNotNull(compositionPlayerInternal).stopRendering();
     } else {
       playbackState = STATE_READY;
       if (oldPlaybackState != STATE_READY && playWhenReady) {

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

@@ -155,10 +155,10 @@ import androidx.media3.exoplayer.video.PlaybackVideoGraphWrapper;
     try {
       switch (message.what) {
         case MSG_START_RENDERING:
-          playbackAudioGraphWrapper.startRendering();
+          startRenderingInternal();
           break;
         case MSG_STOP_RENDERING:
-          playbackAudioGraphWrapper.stopRendering();
+          stopRenderingInternal();
           break;
         case MSG_SET_VOLUME:
           playbackAudioGraphWrapper.setVolume(/* volume= */ (float) message.obj);
@@ -210,6 +210,16 @@ import androidx.media3.exoplayer.video.PlaybackVideoGraphWrapper;
     }
   }
 
+  public void startRenderingInternal() {
+    playbackAudioGraphWrapper.startRendering();
+    playbackVideoGraphWrapper.startRendering();
+  }
+
+  public void stopRenderingInternal() {
+    playbackAudioGraphWrapper.stopRendering();
+    playbackVideoGraphWrapper.stopRendering();
+  }
+
   private void clearOutputSurfaceInternal() {
     try {
       playbackVideoGraphWrapper.clearOutputSurfaceInfo();