Emit onPositionDiscontinuity event when silence is skipped

Issue: #765
PiperOrigin-RevId: 584024654

RELEASENOTES.md

@@ -22,6 +22,8 @@
         `ImageRenderer.ImageOutput`.
     *   `DefaultRenderersFactory` now provides an `ImageRenderer` to the player
         by default with null `ImageOutput` and `ImageDecoder.Factory.DEFAULT`.
+    *   Emit `Player.Listener.onPositionDiscontinuity` event when silence is
+        skipped ([#765](https://github.com/androidx/media/issues/765)).
 *   Transformer:
     *   Add support for flattening H.265/HEVC SEF slow motion videos.
     *   Increase transmuxing speed, especially for 'remove video' edits.

api.txt

@@ -826,6 +826,7 @@ package androidx.media3.common {
     field public static final int DISCONTINUITY_REASON_REMOVE = 4; // 0x4
     field public static final int DISCONTINUITY_REASON_SEEK = 1; // 0x1
     field public static final int DISCONTINUITY_REASON_SEEK_ADJUSTMENT = 2; // 0x2
+    field public static final int DISCONTINUITY_REASON_SILENCE_SKIP = 6; // 0x6
     field public static final int DISCONTINUITY_REASON_SKIP = 3; // 0x3
     field public static final int EVENT_AUDIO_ATTRIBUTES_CHANGED = 20; // 0x14
     field public static final int EVENT_AUDIO_SESSION_ID = 21; // 0x15
@@ -894,7 +895,7 @@ package androidx.media3.common {
     field public static final androidx.media3.common.Player.Commands EMPTY;
   }
 
-  @IntDef({androidx.media3.common.Player.DISCONTINUITY_REASON_AUTO_TRANSITION, androidx.media3.common.Player.DISCONTINUITY_REASON_SEEK, androidx.media3.common.Player.DISCONTINUITY_REASON_SEEK_ADJUSTMENT, androidx.media3.common.Player.DISCONTINUITY_REASON_SKIP, androidx.media3.common.Player.DISCONTINUITY_REASON_REMOVE, androidx.media3.common.Player.DISCONTINUITY_REASON_INTERNAL}) @java.lang.annotation.Documented @java.lang.annotation.Retention(java.lang.annotation.RetentionPolicy.SOURCE) @java.lang.annotation.Target({java.lang.annotation.ElementType.FIELD, java.lang.annotation.ElementType.METHOD, java.lang.annotation.ElementType.PARAMETER, java.lang.annotation.ElementType.LOCAL_VARIABLE, java.lang.annotation.ElementType.TYPE_USE}) public static @interface Player.DiscontinuityReason {
+  @IntDef({androidx.media3.common.Player.DISCONTINUITY_REASON_AUTO_TRANSITION, androidx.media3.common.Player.DISCONTINUITY_REASON_SEEK, androidx.media3.common.Player.DISCONTINUITY_REASON_SEEK_ADJUSTMENT, androidx.media3.common.Player.DISCONTINUITY_REASON_SKIP, androidx.media3.common.Player.DISCONTINUITY_REASON_REMOVE, androidx.media3.common.Player.DISCONTINUITY_REASON_INTERNAL, androidx.media3.common.Player.DISCONTINUITY_REASON_SILENCE_SKIP}) @java.lang.annotation.Documented @java.lang.annotation.Retention(java.lang.annotation.RetentionPolicy.SOURCE) @java.lang.annotation.Target({java.lang.annotation.ElementType.FIELD, java.lang.annotation.ElementType.METHOD, java.lang.annotation.ElementType.PARAMETER, java.lang.annotation.ElementType.LOCAL_VARIABLE, java.lang.annotation.ElementType.TYPE_USE}) public static @interface Player.DiscontinuityReason {
   }
 
   @IntDef({androidx.media3.common.Player.EVENT_TIMELINE_CHANGED, androidx.media3.common.Player.EVENT_MEDIA_ITEM_TRANSITION, androidx.media3.common.Player.EVENT_TRACKS_CHANGED, androidx.media3.common.Player.EVENT_IS_LOADING_CHANGED, androidx.media3.common.Player.EVENT_PLAYBACK_STATE_CHANGED, androidx.media3.common.Player.EVENT_PLAY_WHEN_READY_CHANGED, androidx.media3.common.Player.EVENT_PLAYBACK_SUPPRESSION_REASON_CHANGED, androidx.media3.common.Player.EVENT_IS_PLAYING_CHANGED, androidx.media3.common.Player.EVENT_REPEAT_MODE_CHANGED, androidx.media3.common.Player.EVENT_SHUFFLE_MODE_ENABLED_CHANGED, androidx.media3.common.Player.EVENT_PLAYER_ERROR, androidx.media3.common.Player.EVENT_POSITION_DISCONTINUITY, androidx.media3.common.Player.EVENT_PLAYBACK_PARAMETERS_CHANGED, androidx.media3.common.Player.EVENT_AVAILABLE_COMMANDS_CHANGED, androidx.media3.common.Player.EVENT_MEDIA_METADATA_CHANGED, androidx.media3.common.Player.EVENT_PLAYLIST_METADATA_CHANGED, androidx.media3.common.Player.EVENT_SEEK_BACK_INCREMENT_CHANGED, androidx.media3.common.Player.EVENT_SEEK_FORWARD_INCREMENT_CHANGED, androidx.media3.common.Player.EVENT_MAX_SEEK_TO_PREVIOUS_POSITION_CHANGED, androidx.media3.common.Player.EVENT_TRACK_SELECTION_PARAMETERS_CHANGED, androidx.media3.common.Player.EVENT_AUDIO_ATTRIBUTES_CHANGED, androidx.media3.common.Player.EVENT_AUDIO_SESSION_ID, androidx.media3.common.Player.EVENT_VOLUME_CHANGED, androidx.media3.common.Player.EVENT_SKIP_SILENCE_ENABLED_CHANGED, androidx.media3.common.Player.EVENT_SURFACE_SIZE_CHANGED, androidx.media3.common.Player.EVENT_VIDEO_SIZE_CHANGED, androidx.media3.common.Player.EVENT_RENDERED_FIRST_FRAME, androidx.media3.common.Player.EVENT_CUES, androidx.media3.common.Player.EVENT_METADATA, androidx.media3.common.Player.EVENT_DEVICE_INFO_CHANGED, androidx.media3.common.Player.EVENT_DEVICE_VOLUME_CHANGED}) @java.lang.annotation.Documented @java.lang.annotation.Retention(java.lang.annotation.RetentionPolicy.SOURCE) @java.lang.annotation.Target({java.lang.annotation.ElementType.FIELD, java.lang.annotation.ElementType.METHOD, java.lang.annotation.ElementType.PARAMETER, java.lang.annotation.ElementType.LOCAL_VARIABLE, java.lang.annotation.ElementType.TYPE_USE}) public static @interface Player.Event {

libraries/common/src/main/java/androidx/media3/common/Player.java

@@ -1395,7 +1395,8 @@ default void onMetadata(Metadata metadata) {}
     DISCONTINUITY_REASON_SEEK_ADJUSTMENT,
     DISCONTINUITY_REASON_SKIP,
     DISCONTINUITY_REASON_REMOVE,
-    DISCONTINUITY_REASON_INTERNAL
+    DISCONTINUITY_REASON_INTERNAL,
+    DISCONTINUITY_REASON_SILENCE_SKIP
   })
   @interface DiscontinuityReason {}
 
@@ -1427,6 +1428,9 @@ default void onMetadata(Metadata metadata) {}
   /** Discontinuity introduced internally (e.g. by the source). */
   int DISCONTINUITY_REASON_INTERNAL = 5;
 
+  /** Discontinuity introduced by a skipped silence. */
+  int DISCONTINUITY_REASON_SILENCE_SKIP = 6;
+
   /**
    * Reasons for timeline changes. One of {@link #TIMELINE_CHANGE_REASON_PLAYLIST_CHANGED} or {@link
    * #TIMELINE_CHANGE_REASON_SOURCE_UPDATE}.

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

@@ -134,6 +134,13 @@ public long getPositionUs() {
         : Assertions.checkNotNull(rendererClock).getPositionUs();
   }
 
+  @Override
+  public boolean hasSkippedSilenceSinceLastCall() {
+    return isUsingStandaloneClock
+        ? standaloneClock.hasSkippedSilenceSinceLastCall()
+        : Assertions.checkNotNull(rendererClock).hasSkippedSilenceSinceLastCall();
+  }
+
   @Override
   public void setPlaybackParameters(PlaybackParameters playbackParameters) {
     if (rendererClock != null) {

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

@@ -993,7 +993,18 @@ private void updatePlaybackPositions() throws ExoPlaybackException {
               /* isReadingAhead= */ playingPeriodHolder != queue.getReadingPeriod());
       long periodPositionUs = playingPeriodHolder.toPeriodTime(rendererPositionUs);
       maybeTriggerPendingMessages(playbackInfo.positionUs, periodPositionUs);
-      playbackInfo.updatePositionUs(periodPositionUs);
+      if (mediaClock.hasSkippedSilenceSinceLastCall()) {
+        playbackInfo =
+            handlePositionDiscontinuity(
+                playbackInfo.periodId,
+                /* positionUs= */ periodPositionUs,
+                playbackInfo.requestedContentPositionUs,
+                /* discontinuityStartPositionUs= */ periodPositionUs,
+                /* reportDiscontinuity= */ true,
+                Player.DISCONTINUITY_REASON_SILENCE_SKIP);
+      } else {
+        playbackInfo.updatePositionUs(periodPositionUs);
+      }
     }
 
     // Update the buffered position and total buffered duration.

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

@@ -25,6 +25,11 @@ public interface MediaClock {
   /** Returns the current media position in microseconds. */
   long getPositionUs();
 
+  /** Returns whether there is a skipped silence since the last call to this method. */
+  default boolean hasSkippedSilenceSinceLastCall() {
+    return false;
+  }
+
   /**
    * Attempts to set the playback parameters. The media clock may override the speed if changing the
    * playback parameters is not supported.

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

@@ -152,6 +152,9 @@ default void onAudioTrackInitialized(AudioTrackConfig audioTrackConfig) {}
      * @param audioTrackConfig The {@link AudioTrackConfig} of the released {@link AudioTrack}.
      */
     default void onAudioTrackReleased(AudioTrackConfig audioTrackConfig) {}
+
+    /** Called when a period of silence has been skipped. */
+    default void onSilenceSkipped() {}
   }
 
   /** Configuration parameters used for an {@link AudioTrack}. */

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

@@ -165,6 +165,7 @@ public abstract class DecoderAudioRenderer<
   private long outputStreamOffsetUs;
   private final long[] pendingOutputStreamOffsetsUs;
   private int pendingOutputStreamOffsetCount;
+  private boolean hasPendingReportedSkippedSilence;
 
   public DecoderAudioRenderer() {
     this(/* eventHandler= */ null, /* eventListener= */ null);
@@ -577,6 +578,13 @@ public long getPositionUs() {
     return currentPositionUs;
   }
 
+  @Override
+  public boolean hasSkippedSilenceSinceLastCall() {
+    boolean hasPendingReportedSkippedSilence = this.hasPendingReportedSkippedSilence;
+    this.hasPendingReportedSkippedSilence = false;
+    return hasPendingReportedSkippedSilence;
+  }
+
   @Override
   public void setPlaybackParameters(PlaybackParameters playbackParameters) {
     audioSink.setPlaybackParameters(playbackParameters);
@@ -606,6 +614,7 @@ protected void onPositionReset(long positionUs, boolean joining) throws ExoPlayb
     audioSink.flush();
 
     currentPositionUs = positionUs;
+    hasPendingReportedSkippedSilence = false;
     allowPositionDiscontinuity = true;
     inputStreamEnded = false;
     outputStreamEnded = false;
@@ -630,6 +639,7 @@ protected void onDisabled() {
     inputFormat = null;
     audioTrackNeedsConfigure = true;
     setOutputStreamOffsetUs(C.TIME_UNSET);
+    hasPendingReportedSkippedSilence = false;
     try {
       setSourceDrmSession(null);
       releaseDecoder();
@@ -829,6 +839,11 @@ public void onPositionDiscontinuity() {
       DecoderAudioRenderer.this.onPositionDiscontinuity();
     }
 
+    @Override
+    public void onSilenceSkipped() {
+      hasPendingReportedSkippedSilence = true;
+    }
+
     @Override
     public void onPositionAdvancing(long playoutStartSystemTimeMs) {
       eventDispatcher.positionAdvancing(playoutStartSystemTimeMs);

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

@@ -96,6 +96,16 @@ public final class DefaultAudioSink implements AudioSink {
    */
   private static final int AUDIO_TRACK_SMALLER_BUFFER_RETRY_SIZE = 1_000_000;
 
+  /** The minimum duration of the skipped silence to be reported as discontinuity. */
+  private static final int MINIMUM_REPORT_SKIPPED_SILENCE_DURATION_US = 1_000_000;
+
+  /**
+   * The delay of reporting the skipped silence, during which the default audio sink checks if there
+   * is any further skipped silence that is close to the delayed silence. If any, the further
+   * skipped silence will be concatenated to the delayed one.
+   */
+  private static final int REPORT_SKIPPED_SILENCE_DELAY_MS = 100;
+
   /**
    * Thrown when the audio track has provided a spurious timestamp, if {@link
    * #failOnSpuriousAudioTimestamp} is set.
@@ -542,6 +552,9 @@ public DefaultAudioSink build() {
   private boolean offloadDisabledUntilNextConfiguration;
   private boolean isWaitingForOffloadEndOfStreamHandled;
   @Nullable private Looper playbackLooper;
+  private long skippedOutputFrameCountAtLastPosition;
+  private long accumulatedSkippedSilenceDurationUs;
+  private @MonotonicNonNull Handler reportSkippedSilenceHandler;
 
   @RequiresNonNull("#1.audioProcessorChain")
   private DefaultAudioSink(Builder builder) {
@@ -1443,6 +1456,11 @@ public void flush() {
     }
     writeExceptionPendingExceptionHolder.clear();
     initializationExceptionPendingExceptionHolder.clear();
+    skippedOutputFrameCountAtLastPosition = 0;
+    accumulatedSkippedSilenceDurationUs = 0;
+    if (reportSkippedSilenceHandler != null) {
+      checkNotNull(reportSkippedSilenceHandler).removeCallbacksAndMessages(null);
+    }
   }
 
   @Override
@@ -1645,8 +1663,28 @@ private long applyMediaPositionParameters(long positionUs) {
   }
 
   private long applySkipping(long positionUs) {
-    return positionUs
-        + configuration.framesToDurationUs(audioProcessorChain.getSkippedOutputFrameCount());
+    long skippedOutputFrameCountAtCurrentPosition =
+        audioProcessorChain.getSkippedOutputFrameCount();
+    long adjustedPositionUs =
+        positionUs + configuration.framesToDurationUs(skippedOutputFrameCountAtCurrentPosition);
+    if (skippedOutputFrameCountAtCurrentPosition > skippedOutputFrameCountAtLastPosition) {
+      long silenceDurationUs =
+          configuration.framesToDurationUs(
+              skippedOutputFrameCountAtCurrentPosition - skippedOutputFrameCountAtLastPosition);
+      skippedOutputFrameCountAtLastPosition = skippedOutputFrameCountAtCurrentPosition;
+      handleSkippedSilence(silenceDurationUs);
+    }
+    return adjustedPositionUs;
+  }
+
+  private void handleSkippedSilence(long silenceDurationUs) {
+    accumulatedSkippedSilenceDurationUs += silenceDurationUs;
+    if (reportSkippedSilenceHandler == null) {
+      reportSkippedSilenceHandler = new Handler(Looper.myLooper());
+    }
+    reportSkippedSilenceHandler.removeCallbacksAndMessages(null);
+    reportSkippedSilenceHandler.postDelayed(
+        this::maybeReportSkippedSilence, /* delayMillis= */ REPORT_SKIPPED_SILENCE_DELAY_MS);
   }
 
   private boolean isAudioTrackInitialized() {
@@ -2225,6 +2263,16 @@ public void clear() {
     }
   }
 
+  private void maybeReportSkippedSilence() {
+    if (accumulatedSkippedSilenceDurationUs >= MINIMUM_REPORT_SKIPPED_SILENCE_DURATION_US) {
+      // If the existing silence is already long enough, report the silence
+      listener.onSilenceSkipped();
+    }
+    // Reset the accumulated silence anyway as the later silences are far from the current one
+    // and should be treated separately.
+    accumulatedSkippedSilenceDurationUs = 0;
+  }
+
   @RequiresApi(23)
   private static final class AudioDeviceInfoApi23 {
 

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

@@ -118,6 +118,7 @@ public class MediaCodecAudioRenderer extends MediaCodecRenderer implements Media
   private boolean audioSinkNeedsReset;
 
   @Nullable private WakeupListener wakeupListener;
+  private boolean hasPendingReportedSkippedSilence;
 
   /**
    * @param context A context.
@@ -613,6 +614,7 @@ protected void onPositionReset(long positionUs, boolean joining) throws ExoPlayb
     audioSink.flush();
 
     currentPositionUs = positionUs;
+    hasPendingReportedSkippedSilence = false;
     allowPositionDiscontinuity = true;
   }
 
@@ -646,6 +648,7 @@ protected void onDisabled() {
 
   @Override
   protected void onReset() {
+    hasPendingReportedSkippedSilence = false;
     try {
       super.onReset();
     } finally {
@@ -679,6 +682,13 @@ public long getPositionUs() {
     return currentPositionUs;
   }
 
+  @Override
+  public boolean hasSkippedSilenceSinceLastCall() {
+    boolean hasPendingReportedSkippedSilence = this.hasPendingReportedSkippedSilence;
+    this.hasPendingReportedSkippedSilence = false;
+    return hasPendingReportedSkippedSilence;
+  }
+
   @Override
   public void setPlaybackParameters(PlaybackParameters playbackParameters) {
     audioSink.setPlaybackParameters(playbackParameters);
@@ -969,6 +979,11 @@ public void onPositionDiscontinuity() {
       MediaCodecAudioRenderer.this.onPositionDiscontinuity();
     }
 
+    @Override
+    public void onSilenceSkipped() {
+      hasPendingReportedSkippedSilence = true;
+    }
+
     @Override
     public void onPositionAdvancing(long playoutStartSystemTimeMs) {
       eventDispatcher.positionAdvancing(playoutStartSystemTimeMs);

libraries/exoplayer/src/main/java/androidx/media3/exoplayer/util/EventLogger.java

@@ -707,6 +707,8 @@ private static String getDiscontinuityReasonString(@Player.DiscontinuityReason i
         return "SKIP";
       case Player.DISCONTINUITY_REASON_INTERNAL:
         return "INTERNAL";
+      case Player.DISCONTINUITY_REASON_SILENCE_SKIP:
+        return "SILENCE_SKIP";
       default:
         return "?";
     }

libraries/exoplayer/src/test/java/androidx/media3/exoplayer/ExoPlayerTest.java

@@ -14054,6 +14054,80 @@ protected void onStreamChanged(
         .isSameInstanceAs(mediaItem2);
   }
 
+  @Test
+  public void silenceSkipped_playerEmitOnPositionDiscontinuity() throws Exception {
+    Timeline timeline =
+        new FakeTimeline(
+            new TimelineWindowDefinition(
+                /* periodCount= */ 1,
+                /* id= */ 0,
+                /* isSeekable= */ true,
+                /* isDynamic= */ false,
+                /* isLive= */ false,
+                /* isPlaceholder= */ false,
+                /* durationUs= */ 10 * C.MICROS_PER_SECOND,
+                /* defaultPositionUs= */ 0,
+                /* windowOffsetInFirstPeriodUs= */ 0,
+                AdPlaybackState.NONE));
+    FakeMediaClockRenderer audioRenderer =
+        new FakeMediaClockRenderer(C.TRACK_TYPE_AUDIO) {
+          private long offsetUs;
+          private long positionUs;
+          private boolean hasPendingReportedSkippedSilence;
+
+          @Override
+          protected void onStreamChanged(
+              Format[] formats, long startPositionUs, long offsetUs, MediaPeriodId mediaPeriodId) {
+            this.offsetUs = offsetUs;
+            this.positionUs = offsetUs;
+          }
+
+          @Override
+          public long getPositionUs() {
+            // Continuously increase position to let playback progress, and simulate the silence
+            // skip until it reaches some points of time.
+            if (positionUs - offsetUs == 10_000) {
+              hasPendingReportedSkippedSilence = true;
+              positionUs += 30_000;
+            } else {
+              positionUs += 10_000;
+            }
+            return positionUs;
+          }
+
+          @Override
+          public boolean hasSkippedSilenceSinceLastCall() {
+            boolean hasPendingReportedSkippedSilence = this.hasPendingReportedSkippedSilence;
+            if (hasPendingReportedSkippedSilence) {
+              this.hasPendingReportedSkippedSilence = false;
+            }
+            return hasPendingReportedSkippedSilence;
+          }
+
+          @Override
+          public void setPlaybackParameters(PlaybackParameters playbackParameters) {}
+
+          @Override
+          public PlaybackParameters getPlaybackParameters() {
+            return PlaybackParameters.DEFAULT;
+          }
+        };
+    ExoPlayer player = new TestExoPlayerBuilder(context).setRenderers(audioRenderer).build();
+    Player.Listener mockPlayerListener = mock(Player.Listener.class);
+    player.addListener(mockPlayerListener);
+
+    player.setMediaSource(new FakeMediaSource(timeline, ExoPlayerTestRunner.AUDIO_FORMAT));
+    player.prepare();
+    player.play();
+    runUntilPlaybackState(player, Player.STATE_ENDED);
+
+    verify(mockPlayerListener)
+        .onPositionDiscontinuity(any(), any(), eq(Player.DISCONTINUITY_REASON_SILENCE_SKIP));
+    assertThat(audioRenderer.isEnded).isTrue();
+
+    player.release();
+  }
+
   // Internal methods.
 
   private void addWatchAsSystemFeature() {