Rollback of https://github.com/google/ExoPlayer/commit/8da6c35bbbae84c91c49fc2d723224642d1670f9

*** Original commit ***

Keep AudioTrack on flush as default

***

PiperOrigin-RevId: 444327724

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

@@ -453,6 +453,18 @@ 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 sink, releasing any resources that it currently holds. */
   void reset();
 }

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

@@ -125,6 +125,7 @@ public abstract class DecoderAudioRenderer<
   private int encoderDelay;
   private int encoderPadding;
 
+  private boolean experimentalKeepAudioTrackOnSeek;
   private boolean firstStreamSampleRead;
 
   @Nullable private T decoder;
@@ -204,6 +205,19 @@ public abstract class DecoderAudioRenderer<
     audioSinkNeedsConfigure = 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() {
@@ -537,7 +551,12 @@ public abstract class DecoderAudioRenderer<
 
   @Override
   protected void onPositionReset(long positionUs, boolean joining) throws ExoPlaybackException {
-    audioSink.flush();
+    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

@@ -898,7 +898,7 @@ public final class DefaultAudioSink implements AudioSink {
           // We're waiting for playout on the current audio track to finish.
           return false;
         }
-        flushAndReleaseAudioTrack();
+        flush();
       } else {
         // The current audio track can be reused for the new configuration.
         configuration = pendingConfiguration;
@@ -1025,7 +1025,7 @@ public final class DefaultAudioSink implements AudioSink {
 
     if (audioTrackPositionTracker.isStalled(getWrittenFrames())) {
       Log.w(TAG, "Resetting stalled audio track");
-      flushAndReleaseAudioTrack();
+      flush();
       return true;
     }
 
@@ -1315,8 +1315,7 @@ public final class DefaultAudioSink implements AudioSink {
       // The audio attributes are ignored in tunneling mode, so no need to reset.
       return;
     }
-    // audioAttributes change requires the audioTrack to be recreated.
-    flushAndReleaseAudioTrack();
+    flush();
   }
 
   @Override
@@ -1329,8 +1328,7 @@ public final class DefaultAudioSink implements AudioSink {
     if (this.audioSessionId != audioSessionId) {
       this.audioSessionId = audioSessionId;
       externalAudioSessionIdProvided = audioSessionId != C.AUDIO_SESSION_ID_UNSET;
-      // audioSessionId change requires the audioTrack to be recreated.
-      flushAndReleaseAudioTrack();
+      flush();
     }
   }
 
@@ -1358,7 +1356,7 @@ public final class DefaultAudioSink implements AudioSink {
     Assertions.checkState(externalAudioSessionIdProvided);
     if (!tunneling) {
       tunneling = true;
-      flushAndReleaseAudioTrack();
+      flush();
     }
   }
 
@@ -1366,7 +1364,7 @@ public final class DefaultAudioSink implements AudioSink {
   public void disableTunneling() {
     if (tunneling) {
       tunneling = false;
-      flushAndReleaseAudioTrack();
+      flush();
     }
   }
 
@@ -1398,26 +1396,70 @@ public final class DefaultAudioSink implements AudioSink {
 
   @Override
   public void flush() {
-    if (!isAudioTrackInitialized()) {
-      return;
+    if (isAudioTrackInitialized()) {
+      resetSinkStateForFlush();
+
+      if (audioTrackPositionTracker.isPlaying()) {
+        audioTrack.pause();
+      }
+      if (isOffloadedPlayback(audioTrack)) {
+        checkNotNull(offloadStreamEventCallbackV29).unregister(audioTrack);
+      }
+      // AudioTrack.release can take some time, so we call it on a background thread.
+      final AudioTrack toRelease = audioTrack;
+      audioTrack = null;
+      if (Util.SDK_INT < 21 && !externalAudioSessionIdProvided) {
+        // Prior to API level 21, audio sessions are not kept alive once there are no components
+        // associated with them. If we generated the session ID internally, the only component
+        // associated with the session is the audio track that's being released, and therefore
+        // the session will not be kept alive. As a result, we need to generate a new session when
+        // we next create an audio track.
+        audioSessionId = C.AUDIO_SESSION_ID_UNSET;
+      }
+      if (pendingConfiguration != null) {
+        configuration = pendingConfiguration;
+        pendingConfiguration = null;
+      }
+      audioTrackPositionTracker.reset();
+      releasingConditionVariable.close();
+      new Thread("ExoPlayer:AudioTrackReleaseThread") {
+        @Override
+        public void run() {
+          try {
+            toRelease.flush();
+            toRelease.release();
+          } finally {
+            releasingConditionVariable.open();
+          }
+        }
+      }.start();
     }
+    writeExceptionPendingExceptionHolder.clear();
+    initializationExceptionPendingExceptionHolder.clear();
+  }
 
-    // Prior to SDK 25, AudioTrack flush does not work as intended, so it must be released and
-    // reinitialized. (Internal reference: b/143500232)
+  @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) {
-      flushAndReleaseAudioTrack();
+      flush();
       return;
     }
 
     writeExceptionPendingExceptionHolder.clear();
     initializationExceptionPendingExceptionHolder.clear();
 
+    if (!isAudioTrackInitialized()) {
+      return;
+    }
+
     resetSinkStateForFlush();
     if (audioTrackPositionTracker.isPlaying()) {
       audioTrack.pause();
     }
-
     audioTrack.flush();
+
     audioTrackPositionTracker.reset();
     audioTrackPositionTracker.setAudioTrack(
         audioTrack,
@@ -1425,12 +1467,13 @@ public final class DefaultAudioSink implements AudioSink {
         configuration.outputEncoding,
         configuration.outputPcmFrameSize,
         configuration.bufferSize);
+
     startMediaTimeUsNeedsInit = true;
   }
 
   @Override
   public void reset() {
-    flushAndReleaseAudioTrack();
+    flush();
     for (AudioProcessor audioProcessor : toIntPcmAvailableAudioProcessors) {
       audioProcessor.reset();
     }
@@ -1443,51 +1486,6 @@ public final class DefaultAudioSink implements AudioSink {
 
   // Internal methods.
 
-  private void flushAndReleaseAudioTrack() {
-    if (!isAudioTrackInitialized()) {
-      return;
-    }
-
-    writeExceptionPendingExceptionHolder.clear();
-    initializationExceptionPendingExceptionHolder.clear();
-
-    resetSinkStateForFlush();
-    if (audioTrackPositionTracker.isPlaying()) {
-      audioTrack.pause();
-    }
-    if (isOffloadedPlayback(audioTrack)) {
-      checkNotNull(offloadStreamEventCallbackV29).unregister(audioTrack);
-    }
-    // AudioTrack.release can take some time, so we call it on a background thread.
-    final AudioTrack toRelease = audioTrack;
-    audioTrack = null;
-    if (Util.SDK_INT < 21 && !externalAudioSessionIdProvided) {
-      // Prior to API level 21, audio sessions are not kept alive once there are no components
-      // associated with them. If we generated the session ID internally, the only component
-      // associated with the session is the audio track that's being released, and therefore
-      // the session will not be kept alive. As a result, we need to generate a new session when
-      // we next create an audio track.
-      audioSessionId = C.AUDIO_SESSION_ID_UNSET;
-    }
-    if (pendingConfiguration != null) {
-      configuration = pendingConfiguration;
-      pendingConfiguration = null;
-    }
-    audioTrackPositionTracker.reset();
-    releasingConditionVariable.close();
-    new Thread("ExoPlayer:AudioTrackReleaseThread") {
-      @Override
-      public void run() {
-        try {
-          toRelease.flush();
-          toRelease.release();
-        } finally {
-          releasingConditionVariable.open();
-        }
-      }
-    }.start();
-  }
-
   private void resetSinkStateForFlush() {
     submittedPcmBytes = 0;
     submittedEncodedFrames = 0;

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

@@ -160,6 +160,11 @@ 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

@@ -105,6 +105,8 @@ public class MediaCodecAudioRenderer extends MediaCodecRenderer implements Media
   private boolean allowPositionDiscontinuity;
   private boolean audioSinkNeedsConfigure;
 
+  private boolean experimentalKeepAudioTrackOnSeek;
+
   @Nullable private WakeupListener wakeupListener;
 
   /**
@@ -260,6 +262,19 @@ 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
   protected @Capabilities int supportsFormat(MediaCodecSelector mediaCodecSelector, Format format)
       throws DecoderQueryException {
@@ -512,7 +527,11 @@ public class MediaCodecAudioRenderer extends MediaCodecRenderer implements Media
   @Override
   protected void onPositionReset(long positionUs, boolean joining) throws ExoPlaybackException {
     super.onPositionReset(positionUs, joining);
-    audioSink.flush();
+    if (experimentalKeepAudioTrackOnSeek) {
+      audioSink.experimentalFlushWithoutAudioTrackRelease();
+    } else {
+      audioSink.flush();
+    }
 
     currentPositionUs = positionUs;
     allowFirstBufferPositionDiscontinuity = true;

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

@@ -265,15 +265,15 @@ public final class DefaultAudioSinkTest {
   }
 
   @Test
-  public void handleBuffer_afterFlush_doesntThrow() throws Exception {
-    // This is demonstrating that no Exceptions are thrown as a result of handling a buffer after a
-    // flush.
+  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 flush we can successfully queue more input.
-    defaultAudioSink.flush();
+    // After the experimental flush we can successfully queue more input.
+    defaultAudioSink.experimentalFlushWithoutAudioTrackRelease();
     defaultAudioSink.handleBuffer(
         createDefaultSilenceBuffer(),
         /* presentationTimeUs= */ 5_000,
@@ -281,13 +281,13 @@ public final class DefaultAudioSinkTest {
   }
 
   @Test
-  public void getCurrentPosition_afterFlush_returnsUnset() throws Exception {
+  public void getCurrentPosition_returnsUnset_afterExperimentalFlush() throws Exception {
     configureDefaultAudioSink(CHANNEL_COUNT_STEREO);
     defaultAudioSink.handleBuffer(
         createDefaultSilenceBuffer(),
         /* presentationTimeUs= */ 5 * C.MICROS_PER_SECOND,
         /* encodedAccessUnitCount= */ 1);
-    defaultAudioSink.flush();
+    defaultAudioSink.experimentalFlushWithoutAudioTrackRelease();
     assertThat(defaultAudioSink.getCurrentPositionUs(/* sourceEnded= */ false))
         .isEqualTo(CURRENT_POSITION_NOT_SET);
   }