Keep AudioTrack on seek - experimental.

PiperOrigin-RevId: 326622573

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

@@ -362,6 +362,18 @@ public interface AudioSink {
    */
   void flush();
 
+  /**
+   * Flushes the sink, after which it is ready to receive buffers from a new playback position.
+   *
+   * <p>Does not release the {@link AudioTrack} held by the sink.
+   *
+   * <p>This method is experimental, and will be renamed or removed in a future release.
+   *
+   * <p>Only for experimental use as part of {@link
+   * MediaCodecAudioRenderer#experimentalSetEnableKeepAudioTrackOnSeek(boolean)}.
+   */
+  void experimentalFlushWithoutAudioTrackRelease();
+
   /** Resets the renderer, releasing any resources that it currently holds. */
   void reset();
 }

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

@@ -112,6 +112,8 @@ public abstract class DecoderAudioRenderer<
   private int encoderDelay;
   private int encoderPadding;
 
+  private boolean experimentalKeepAudioTrackOnSeek;
+
   @Nullable private T decoder;
 
   @Nullable private DecoderInputBuffer inputBuffer;
@@ -185,6 +187,19 @@ public abstract class DecoderAudioRenderer<
     audioTrackNeedsConfigure = true;
   }
 
+  /**
+   * Sets whether to enable the experimental feature that keeps and flushes the {@link
+   * android.media.AudioTrack} when a seek occurs, as opposed to releasing and reinitialising. Off
+   * by default.
+   *
+   * <p>This method is experimental, and will be renamed or removed in a future release.
+   *
+   * @param enableKeepAudioTrackOnSeek Whether to keep the {@link android.media.AudioTrack} on seek.
+   */
+  public void experimentalSetEnableKeepAudioTrackOnSeek(boolean enableKeepAudioTrackOnSeek) {
+    this.experimentalKeepAudioTrackOnSeek = enableKeepAudioTrackOnSeek;
+  }
+
   @Override
   @Nullable
   public MediaClock getMediaClock() {
@@ -507,7 +522,12 @@ public abstract class DecoderAudioRenderer<
 
   @Override
   protected void onPositionReset(long positionUs, boolean joining) throws ExoPlaybackException {
+    if (experimentalKeepAudioTrackOnSeek) {
+      audioSink.experimentalFlushWithoutAudioTrackRelease();
+    } else {
       audioSink.flush();
+    }
+
     currentPositionUs = positionUs;
     allowFirstBufferPositionDiscontinuity = true;
     allowPositionDiscontinuity = true;

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

@@ -279,7 +279,9 @@ public final class DefaultAudioSink implements AudioSink {
   @MonotonicNonNull private StreamEventCallbackV29 offloadStreamEventCallbackV29;
 
   @Nullable private Listener listener;
-  /** Used to keep the audio session active on pre-V21 builds (see {@link #initialize(long)}). */
+  /**
+   * Used to keep the audio session active on pre-V21 builds (see {@link #initializeAudioTrack()}).
+   */
   @Nullable private AudioTrack keepSessionIdAudioTrack;
 
   @Nullable private Configuration pendingConfiguration;
@@ -300,6 +302,7 @@ public final class DefaultAudioSink implements AudioSink {
   private long writtenEncodedFrames;
   private int framesPerEncodedSample;
   private boolean startMediaTimeUsNeedsSync;
+  private boolean startMediaTimeUsNeedsInit;
   private long startMediaTimeUs;
   private float volume;
 
@@ -470,7 +473,7 @@ public final class DefaultAudioSink implements AudioSink {
 
   @Override
   public long getCurrentPositionUs(boolean sourceEnded) {
-    if (!isInitialized()) {
+    if (!isAudioTrackInitialized() || startMediaTimeUsNeedsInit) {
       return CURRENT_POSITION_NOT_SET;
     }
     long positionUs = audioTrackPositionTracker.getCurrentPositionUs(sourceEnded);
@@ -581,7 +584,7 @@ public final class DefaultAudioSink implements AudioSink {
             specifiedBufferSize,
             canApplyPlaybackParameters,
             availableAudioProcessors);
-    if (isInitialized()) {
+    if (isAudioTrackInitialized()) {
       this.pendingConfiguration = pendingConfiguration;
     } else {
       configuration = pendingConfiguration;
@@ -612,7 +615,7 @@ public final class DefaultAudioSink implements AudioSink {
     }
   }
 
-  private void initialize(long presentationTimeUs) throws InitializationException {
+  private void initializeAudioTrack() throws InitializationException {
     // If we're asynchronously releasing a previous audio track then we block until it has been
     // released. This guarantees that we cannot end up in a state where we have multiple audio
     // track instances. Without this guarantee it would be possible, in extreme cases, to exhaust
@@ -647,17 +650,9 @@ public final class DefaultAudioSink implements AudioSink {
       }
     }
 
-    startMediaTimeUs = max(0, presentationTimeUs);
-    startMediaTimeUsNeedsSync = false;
-
-    if (enableAudioTrackPlaybackParams && Util.SDK_INT >= 23) {
-      setAudioTrackPlaybackSpeedV23(audioTrackPlaybackSpeed);
-    }
-    applyAudioProcessorPlaybackSpeedAndSkipSilence(presentationTimeUs);
-
     audioTrackPositionTracker.setAudioTrack(
         audioTrack,
-        configuration.outputMode == OUTPUT_MODE_PASSTHROUGH,
+        /* isPassthrough= */ configuration.outputMode == OUTPUT_MODE_PASSTHROUGH,
         configuration.outputEncoding,
         configuration.outputPcmFrameSize,
         configuration.bufferSize);
@@ -667,12 +662,14 @@ public final class DefaultAudioSink implements AudioSink {
       audioTrack.attachAuxEffect(auxEffectInfo.effectId);
       audioTrack.setAuxEffectSendLevel(auxEffectInfo.sendLevel);
     }
+
+    startMediaTimeUsNeedsInit = true;
   }
 
   @Override
   public void play() {
     playing = true;
-    if (isInitialized()) {
+    if (isAudioTrackInitialized()) {
       audioTrackPositionTracker.start();
       audioTrack.play();
     }
@@ -716,8 +713,20 @@ public final class DefaultAudioSink implements AudioSink {
       applyAudioProcessorPlaybackSpeedAndSkipSilence(presentationTimeUs);
     }
 
-    if (!isInitialized()) {
-      initialize(presentationTimeUs);
+    if (!isAudioTrackInitialized()) {
+      initializeAudioTrack();
+    }
+
+    if (startMediaTimeUsNeedsInit) {
+      startMediaTimeUs = max(0, presentationTimeUs);
+      startMediaTimeUsNeedsSync = false;
+      startMediaTimeUsNeedsInit = false;
+
+      if (enableAudioTrackPlaybackParams && Util.SDK_INT >= 23) {
+        setAudioTrackPlaybackSpeedV23(audioTrackPlaybackSpeed);
+      }
+      applyAudioProcessorPlaybackSpeedAndSkipSilence(presentationTimeUs);
+
       if (playing) {
         play();
       }
@@ -945,7 +954,7 @@ public final class DefaultAudioSink implements AudioSink {
 
   @Override
   public void playToEndOfStream() throws WriteException {
-    if (!handledEndOfStream && isInitialized() && drainToEndOfStream()) {
+    if (!handledEndOfStream && isAudioTrackInitialized() && drainToEndOfStream()) {
       playPendingData();
       handledEndOfStream = true;
     }
@@ -987,12 +996,13 @@ public final class DefaultAudioSink implements AudioSink {
 
   @Override
   public boolean isEnded() {
-    return !isInitialized() || (handledEndOfStream && !hasPendingData());
+    return !isAudioTrackInitialized() || (handledEndOfStream && !hasPendingData());
   }
 
   @Override
   public boolean hasPendingData() {
-    return isInitialized() && audioTrackPositionTracker.hasPendingData(getWrittenFrames());
+    return isAudioTrackInitialized()
+        && audioTrackPositionTracker.hasPendingData(getWrittenFrames());
   }
 
   @Override
@@ -1090,7 +1100,7 @@ public final class DefaultAudioSink implements AudioSink {
   }
 
   private void setVolumeInternal() {
-    if (!isInitialized()) {
+    if (!isAudioTrackInitialized()) {
       // Do nothing.
     } else if (Util.SDK_INT >= 21) {
       setVolumeInternalV21(audioTrack, volume);
@@ -1102,14 +1112,14 @@ public final class DefaultAudioSink implements AudioSink {
   @Override
   public void pause() {
     playing = false;
-    if (isInitialized() && audioTrackPositionTracker.pause()) {
+    if (isAudioTrackInitialized() && audioTrackPositionTracker.pause()) {
       audioTrack.pause();
     }
   }
 
   @Override
   public void flush() {
-    if (isInitialized()) {
+    if (isAudioTrackInitialized()) {
       resetSinkStateForFlush();
 
       if (audioTrackPositionTracker.isPlaying()) {
@@ -1142,6 +1152,36 @@ public final class DefaultAudioSink implements AudioSink {
   }
 
   @Override
+  public void experimentalFlushWithoutAudioTrackRelease() {
+    // Prior to SDK 25, AudioTrack flush does not work as intended, and therefore it must be
+    // released and reinitialized. (Internal reference: b/143500232)
+    if (Util.SDK_INT < 25) {
+      flush();
+      return;
+    }
+
+    if (!isAudioTrackInitialized()) {
+      return;
+    }
+
+    resetSinkStateForFlush();
+    if (audioTrackPositionTracker.isPlaying()) {
+      audioTrack.pause();
+    }
+    audioTrack.flush();
+
+    audioTrackPositionTracker.reset();
+    audioTrackPositionTracker.setAudioTrack(
+        audioTrack,
+        /* isPassthrough= */ configuration.outputMode == OUTPUT_MODE_PASSTHROUGH,
+        configuration.outputEncoding,
+        configuration.outputPcmFrameSize,
+        configuration.bufferSize);
+
+    startMediaTimeUsNeedsInit = true;
+  }
+
+  @Override
   public void reset() {
     flush();
     releaseKeepSessionIdAudioTrack();
@@ -1204,7 +1244,7 @@ public final class DefaultAudioSink implements AudioSink {
 
   @RequiresApi(23)
   private void setAudioTrackPlaybackSpeedV23(float audioTrackPlaybackSpeed) {
-    if (isInitialized()) {
+    if (isAudioTrackInitialized()) {
       PlaybackParams playbackParams =
           new PlaybackParams()
               .allowDefaults()
@@ -1233,7 +1273,7 @@ public final class DefaultAudioSink implements AudioSink {
               skipSilence,
               /* mediaTimeUs= */ C.TIME_UNSET,
               /* audioTrackPositionUs= */ C.TIME_UNSET);
-      if (isInitialized()) {
+      if (isAudioTrackInitialized()) {
         // Drain the audio processors so we can determine the frame position at which the new
         // parameters apply.
         this.afterDrainParameters = mediaPositionParameters;
@@ -1313,7 +1353,7 @@ public final class DefaultAudioSink implements AudioSink {
         + configuration.framesToDurationUs(audioProcessorChain.getSkippedOutputFrameCount());
   }
 
-  private boolean isInitialized() {
+  private boolean isAudioTrackInitialized() {
     return audioTrack != null;
   }
 

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

@@ -148,6 +148,11 @@ public class ForwardingAudioSink implements AudioSink {
   }
 
   @Override
+  public void experimentalFlushWithoutAudioTrackRelease() {
+    sink.experimentalFlushWithoutAudioTrackRelease();
+  }
+
+  @Override
   public void reset() {
     sink.reset();
   }

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

@@ -97,6 +97,8 @@ public class MediaCodecAudioRenderer extends MediaCodecRenderer implements Media
   private boolean allowFirstBufferPositionDiscontinuity;
   private boolean allowPositionDiscontinuity;
 
+  private boolean experimentalKeepAudioTrackOnSeek;
+
   @Nullable private WakeupListener wakeupListener;
 
   /**
@@ -205,6 +207,19 @@ public class MediaCodecAudioRenderer extends MediaCodecRenderer implements Media
     return TAG;
   }
 
+  /**
+   * Sets whether to enable the experimental feature that keeps and flushes the {@link
+   * android.media.AudioTrack} when a seek occurs, as opposed to releasing and reinitialising. Off
+   * by default.
+   *
+   * <p>This method is experimental, and will be renamed or removed in a future release.
+   *
+   * @param enableKeepAudioTrackOnSeek Whether to keep the {@link android.media.AudioTrack} on seek.
+   */
+  public void experimentalSetEnableKeepAudioTrackOnSeek(boolean enableKeepAudioTrackOnSeek) {
+    this.experimentalKeepAudioTrackOnSeek = enableKeepAudioTrackOnSeek;
+  }
+
   @Override
   @Capabilities
   protected int supportsFormat(MediaCodecSelector mediaCodecSelector, Format format)
@@ -465,7 +480,12 @@ public class MediaCodecAudioRenderer extends MediaCodecRenderer implements Media
   @Override
   protected void onPositionReset(long positionUs, boolean joining) throws ExoPlaybackException {
     super.onPositionReset(positionUs, joining);
+    if (experimentalKeepAudioTrackOnSeek) {
+      audioSink.experimentalFlushWithoutAudioTrackRelease();
+    } else {
       audioSink.flush();
+    }
+
     currentPositionUs = positionUs;
     allowFirstBufferPositionDiscontinuity = true;
     allowPositionDiscontinuity = true;

library/core/src/test/java/com/google/android/exoplayer2/audio/DefaultAudioSinkTest.java

@@ -15,6 +15,7 @@
  */
 package com.google.android.exoplayer2.audio;
 
+import static com.google.android.exoplayer2.audio.AudioSink.CURRENT_POSITION_NOT_SET;
 import static com.google.android.exoplayer2.audio.AudioSink.SINK_FORMAT_SUPPORTED_DIRECTLY;
 import static com.google.android.exoplayer2.audio.AudioSink.SINK_FORMAT_SUPPORTED_WITH_TRANSCODING;
 import static com.google.common.truth.Truth.assertThat;
@@ -275,6 +276,34 @@ public final class DefaultAudioSinkTest {
     assertThat(defaultAudioSink.supportsFormat(aacLcFormat)).isFalse();
   }
 
+  @Test
+  public void handlesBufferAfterExperimentalFlush() throws Exception {
+    // This is demonstrating that no Exceptions are thrown as a result of handling a buffer after an
+    // experimental flush.
+    configureDefaultAudioSink(CHANNEL_COUNT_STEREO);
+    defaultAudioSink.handleBuffer(
+        createDefaultSilenceBuffer(), /* presentationTimeUs= */ 0, /* encodedAccessUnitCount= */ 1);
+
+    // After the experimental flush we can successfully queue more input.
+    defaultAudioSink.experimentalFlushWithoutAudioTrackRelease();
+    defaultAudioSink.handleBuffer(
+        createDefaultSilenceBuffer(),
+        /* presentationTimeUs= */ 5_000,
+        /* encodedAccessUnitCount= */ 1);
+  }
+
+  @Test
+  public void getCurrentPosition_returnsUnset_afterExperimentalFlush() throws Exception {
+    configureDefaultAudioSink(CHANNEL_COUNT_STEREO);
+    defaultAudioSink.handleBuffer(
+        createDefaultSilenceBuffer(),
+        /* presentationTimeUs= */ 5 * C.MICROS_PER_SECOND,
+        /* encodedAccessUnitCount= */ 1);
+    defaultAudioSink.experimentalFlushWithoutAudioTrackRelease();
+    assertThat(defaultAudioSink.getCurrentPositionUs(/* sourceEnded= */ false))
+        .isEqualTo(CURRENT_POSITION_NOT_SET);
+  }
+
   private void configureDefaultAudioSink(int channelCount) throws AudioSink.ConfigurationException {
     configureDefaultAudioSink(channelCount, /* trimStartFrames= */ 0, /* trimEndFrames= */ 0);
   }