Move underrun detection into AudioTrack.

This removes duplication from SimpleDecoderAudioRenderer and
MediaCodecAudioRenderer.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=139187254

library/src/main/java/com/google/android/exoplayer2/audio/AudioTrack.java

@@ -15,6 +15,7 @@
  */
 package com.google.android.exoplayer2.audio;
 
+import android.annotation.SuppressLint;
 import android.annotation.TargetApi;
 import android.media.AudioFormat;
 import android.media.AudioTimestamp;
@@ -54,6 +55,24 @@ import java.nio.ByteBuffer;
  */
 public final class AudioTrack {
 
+  /**
+   * Listener for audio track events.
+   */
+  public interface Listener {
+
+    /**
+     * Called when the audio track underruns.
+     *
+     * @param bufferSize The size of the track's buffer, in bytes.
+     * @param bufferSizeMs The size of the track's buffer, in milliseconds, if it is configured for
+     *     PCM output. {@link C#TIME_UNSET} if it is configured for passthrough output, as the
+     *     buffered media can have a variable bitrate so the duration may be unknown.
+     * @param elapsedSinceLastFeedMs The time since the track was last fed data, in milliseconds.
+     */
+    void onUnderrun(int bufferSize, long bufferSizeMs, long elapsedSinceLastFeedMs);
+
+  }
+
   /**
    * Thrown when a failure occurs initializing an {@link android.media.AudioTrack}.
    */
@@ -152,6 +171,40 @@ public final class AudioTrack {
    */
   private static final int BUFFER_MULTIPLICATION_FACTOR = 4;
 
+  /**
+   * @see android.media.AudioTrack#PLAYSTATE_STOPPED
+   */
+  private static final int PLAYSTATE_STOPPED = android.media.AudioTrack.PLAYSTATE_STOPPED;
+  /**
+   * @see android.media.AudioTrack#PLAYSTATE_PAUSED
+   */
+  private static final int PLAYSTATE_PAUSED = android.media.AudioTrack.PLAYSTATE_PAUSED;
+  /**
+   * @see android.media.AudioTrack#PLAYSTATE_PLAYING
+   */
+  private static final int PLAYSTATE_PLAYING = android.media.AudioTrack.PLAYSTATE_PLAYING;
+  /**
+   * @see android.media.AudioTrack#ERROR_BAD_VALUE
+   */
+  private static final int ERROR_BAD_VALUE = android.media.AudioTrack.ERROR_BAD_VALUE;
+  /**
+   * @see android.media.AudioTrack#MODE_STATIC
+   */
+  private static final int MODE_STATIC = android.media.AudioTrack.MODE_STATIC;
+  /**
+   * @see android.media.AudioTrack#MODE_STREAM
+   */
+  private static final int MODE_STREAM = android.media.AudioTrack.MODE_STREAM;
+  /**
+   * @see android.media.AudioTrack#STATE_INITIALIZED
+   */
+  private static final int STATE_INITIALIZED = android.media.AudioTrack.STATE_INITIALIZED;
+  /**
+   * @see android.media.AudioTrack#WRITE_NON_BLOCKING
+   */
+  @SuppressLint("InlinedApi")
+  private static final int WRITE_NON_BLOCKING = android.media.AudioTrack.WRITE_NON_BLOCKING;
+
   private static final String TAG = "AudioTrack";
 
   /**
@@ -197,6 +250,7 @@ public final class AudioTrack {
 
   private final AudioCapabilities audioCapabilities;
   private final int streamType;
+  private final Listener listener;
   private final ConditionVariable releasingConditionVariable;
   private final long[] playheadOffsets;
   private final AudioTrackUtil audioTrackUtil;
@@ -242,13 +296,18 @@ public final class AudioTrack {
   private ByteBuffer resampledBuffer;
   private boolean useResampledBuffer;
 
+  private boolean hasData;
+  private long lastFeedElapsedRealtimeMs;
+
   /**
    * @param audioCapabilities The current audio capabilities.
    * @param streamType The type of audio stream for the underlying {@link android.media.AudioTrack}.
+   * @param listener Listener for audio track events.
    */
-  public AudioTrack(AudioCapabilities audioCapabilities, int streamType) {
+  public AudioTrack(AudioCapabilities audioCapabilities, int streamType, Listener listener) {
     this.audioCapabilities = audioCapabilities;
     this.streamType = streamType;
+    this.listener = listener;
     releasingConditionVariable = new ConditionVariable(true);
     if (Util.SDK_INT >= 18) {
       try {
@@ -305,7 +364,7 @@ public final class AudioTrack {
       return CURRENT_POSITION_NOT_SET;
     }
 
-    if (audioTrack.getPlayState() == android.media.AudioTrack.PLAYSTATE_PLAYING) {
+    if (audioTrack.getPlayState() == PLAYSTATE_PLAYING) {
       maybeSampleSyncParams();
     }
 
@@ -424,7 +483,7 @@ public final class AudioTrack {
     } else {
       int minBufferSize =
           android.media.AudioTrack.getMinBufferSize(sampleRate, channelConfig, targetEncoding);
-      Assertions.checkState(minBufferSize != android.media.AudioTrack.ERROR_BAD_VALUE);
+      Assertions.checkState(minBufferSize != ERROR_BAD_VALUE);
       int multipliedBufferSize = minBufferSize * BUFFER_MULTIPLICATION_FACTOR;
       int minAppBufferSize = (int) durationUsToFrames(MIN_BUFFER_DURATION_US) * pcmFrameSize;
       int maxAppBufferSize = (int) Math.max(minBufferSize,
@@ -453,11 +512,11 @@ public final class AudioTrack {
 
     if (sessionId == SESSION_ID_NOT_SET) {
       audioTrack = new android.media.AudioTrack(streamType, sampleRate, channelConfig,
-          targetEncoding, bufferSize, android.media.AudioTrack.MODE_STREAM);
+          targetEncoding, bufferSize, MODE_STREAM);
     } else {
       // Re-attach to the same audio session.
       audioTrack = new android.media.AudioTrack(streamType, sampleRate, channelConfig,
-          targetEncoding, bufferSize, android.media.AudioTrack.MODE_STREAM, sessionId);
+          targetEncoding, bufferSize, MODE_STREAM, sessionId);
     }
     checkAudioTrackInitialized();
 
@@ -476,42 +535,17 @@ public final class AudioTrack {
           @C.PcmEncoding int encoding = C.ENCODING_PCM_16BIT;
           int bufferSize = 2; // Use a two byte buffer, as it is not actually used for playback.
           keepSessionIdAudioTrack = new android.media.AudioTrack(streamType, sampleRate,
-              channelConfig, encoding, bufferSize, android.media.AudioTrack.MODE_STATIC, sessionId);
+              channelConfig, encoding, bufferSize, MODE_STATIC, sessionId);
         }
       }
     }
 
     audioTrackUtil.reconfigure(audioTrack, needsPassthroughWorkarounds());
     setAudioTrackVolume();
+    hasData = false;
     return sessionId;
   }
 
-  /**
-   * Returns the size of this {@link AudioTrack}'s buffer in bytes.
-   * <p>
-   * The value returned from this method may change as a result of calling one of the
-   * {@link #configure} methods.
-   *
-   * @return The size of the buffer in bytes.
-   */
-  public int getBufferSize() {
-    return bufferSize;
-  }
-
-  /**
-   * Returns the size of the buffer in microseconds for PCM {@link AudioTrack}s, or
-   * {@link C#TIME_UNSET} for passthrough {@link AudioTrack}s.
-   * <p>
-   * The value returned from this method may change as a result of calling one of the
-   * {@link #configure} methods.
-   *
-   * @return The size of the buffer in microseconds for PCM {@link AudioTrack}s, or
-   *     {@link C#TIME_UNSET} for passthrough {@link AudioTrack}s.
-   */
-  public long getBufferSizeUs() {
-    return bufferSizeUs;
-  }
-
   /**
    * Starts or resumes playing audio if the audio track has been initialized.
    */
@@ -553,6 +587,18 @@ public final class AudioTrack {
    * @throws WriteException If an error occurs writing the audio data.
    */
   public int handleBuffer(ByteBuffer buffer, long presentationTimeUs) throws WriteException {
+    boolean hadData = hasData;
+    hasData = hasPendingData();
+    if (hadData && !hasData && audioTrack.getPlayState() != PLAYSTATE_STOPPED) {
+      long elapsedSinceLastFeedMs = SystemClock.elapsedRealtime() - lastFeedElapsedRealtimeMs;
+      listener.onUnderrun(bufferSize, C.usToMs(bufferSizeUs), elapsedSinceLastFeedMs);
+    }
+    int result = writeBuffer(buffer, presentationTimeUs);
+    lastFeedElapsedRealtimeMs = SystemClock.elapsedRealtime();
+    return result;
+  }
+
+  private int writeBuffer(ByteBuffer buffer, long presentationTimeUs) throws WriteException {
     boolean isNewSourceBuffer = currentSourceBuffer == null;
     Assertions.checkState(isNewSourceBuffer || currentSourceBuffer == buffer);
     currentSourceBuffer = buffer;
@@ -560,14 +606,14 @@ public final class AudioTrack {
     if (needsPassthroughWorkarounds()) {
       // An AC-3 audio track continues to play data written while it is paused. Stop writing so its
       // buffer empties. See [Internal: b/18899620].
-      if (audioTrack.getPlayState() == android.media.AudioTrack.PLAYSTATE_PAUSED) {
+      if (audioTrack.getPlayState() == PLAYSTATE_PAUSED) {
         return 0;
       }
 
       // A new AC-3 audio track's playback position continues to increase from the old track's
       // position for a short time after is has been released. Avoid writing data until the playback
       // head position actually returns to zero.
-      if (audioTrack.getPlayState() == android.media.AudioTrack.PLAYSTATE_STOPPED
+      if (audioTrack.getPlayState() == PLAYSTATE_STOPPED
           && audioTrackUtil.getPlaybackHeadPosition() != 0) {
         return 0;
       }
@@ -745,7 +791,7 @@ public final class AudioTrack {
       latencyUs = 0;
       resetSyncParams();
       int playState = audioTrack.getPlayState();
-      if (playState == android.media.AudioTrack.PLAYSTATE_PLAYING) {
+      if (playState == PLAYSTATE_PLAYING) {
         audioTrack.pause();
       }
       // AudioTrack.release can take some time, so we call it on a background thread.
@@ -894,7 +940,7 @@ public final class AudioTrack {
    */
   private void checkAudioTrackInitialized() throws InitializationException {
     int state = audioTrack.getState();
-    if (state == android.media.AudioTrack.STATE_INITIALIZED) {
+    if (state == STATE_INITIALIZED) {
       return;
     }
     // The track is not successfully initialized. Release and null the track.
@@ -952,7 +998,7 @@ public final class AudioTrack {
    */
   private boolean overrideHasPendingData() {
     return needsPassthroughWorkarounds()
-        && audioTrack.getPlayState() == android.media.AudioTrack.PLAYSTATE_PAUSED
+        && audioTrack.getPlayState() == PLAYSTATE_PAUSED
         && audioTrack.getPlaybackHeadPosition() == 0;
   }
 
@@ -1063,7 +1109,7 @@ public final class AudioTrack {
   @TargetApi(21)
   private static int writeNonBlockingV21(
       android.media.AudioTrack audioTrack, ByteBuffer buffer, int size) {
-    return audioTrack.write(buffer, size, android.media.AudioTrack.WRITE_NON_BLOCKING);
+    return audioTrack.write(buffer, size, WRITE_NON_BLOCKING);
   }
 
   @TargetApi(21)
@@ -1156,7 +1202,7 @@ public final class AudioTrack {
       }
 
       int state = audioTrack.getPlayState();
-      if (state == android.media.AudioTrack.PLAYSTATE_STOPPED) {
+      if (state == PLAYSTATE_STOPPED) {
         // The audio track hasn't been started.
         return 0;
       }
@@ -1166,7 +1212,7 @@ public final class AudioTrack {
         // Work around an issue with passthrough/direct AudioTracks on platform API versions 21/22
         // where the playback head position jumps back to zero on paused passthrough/direct audio
         // tracks. See [Internal: b/19187573].
-        if (state == android.media.AudioTrack.PLAYSTATE_PAUSED && rawPlaybackHeadPosition == 0) {
+        if (state == PLAYSTATE_PAUSED && rawPlaybackHeadPosition == 0) {
           passthroughWorkaroundPauseOffset = lastRawPlaybackHeadPosition;
         }
         rawPlaybackHeadPosition += passthroughWorkaroundPauseOffset;

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

@@ -23,7 +23,6 @@ import android.media.MediaFormat;
 import android.media.PlaybackParams;
 import android.media.audiofx.Virtualizer;
 import android.os.Handler;
-import android.os.SystemClock;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.ExoPlaybackException;
 import com.google.android.exoplayer2.Format;
@@ -43,7 +42,8 @@ import java.nio.ByteBuffer;
  * Decodes and renders audio using {@link MediaCodec} and {@link AudioTrack}.
  */
 @TargetApi(16)
-public class MediaCodecAudioRenderer extends MediaCodecRenderer implements MediaClock {
+public class MediaCodecAudioRenderer extends MediaCodecRenderer implements MediaClock,
+    AudioTrack.Listener {
 
   private final EventDispatcher eventDispatcher;
   private final AudioTrack audioTrack;
@@ -55,9 +55,6 @@ public class MediaCodecAudioRenderer extends MediaCodecRenderer implements Media
   private long currentPositionUs;
   private boolean allowPositionDiscontinuity;
 
-  private boolean audioTrackHasData;
-  private long lastFeedElapsedRealtimeMs;
-
   /**
    * @param mediaCodecSelector A decoder selector.
    */
@@ -136,7 +133,7 @@ public class MediaCodecAudioRenderer extends MediaCodecRenderer implements Media
       int streamType) {
     super(C.TRACK_TYPE_AUDIO, mediaCodecSelector, drmSessionManager, playClearSamplesWithoutKeys);
     audioSessionId = AudioTrack.SESSION_ID_NOT_SET;
-    audioTrack = new AudioTrack(audioCapabilities, streamType);
+    audioTrack = new AudioTrack(audioCapabilities, streamType, this);
     eventDispatcher = new EventDispatcher(eventHandler, eventListener);
   }
 
@@ -341,29 +338,17 @@ public class MediaCodecAudioRenderer extends MediaCodecRenderer implements Media
         } else {
           audioTrack.initialize(audioSessionId);
         }
-        audioTrackHasData = false;
       } catch (AudioTrack.InitializationException e) {
         throw ExoPlaybackException.createForRenderer(e, getIndex());
       }
       if (getState() == STATE_STARTED) {
         audioTrack.play();
       }
-    } else {
-      // Check for AudioTrack underrun.
-      boolean audioTrackHadData = audioTrackHasData;
-      audioTrackHasData = audioTrack.hasPendingData();
-      if (audioTrackHadData && !audioTrackHasData && getState() == STATE_STARTED) {
-        long elapsedSinceLastFeedMs = SystemClock.elapsedRealtime() - lastFeedElapsedRealtimeMs;
-        long bufferSizeMs = C.usToMs(audioTrack.getBufferSizeUs());
-        eventDispatcher.audioTrackUnderrun(audioTrack.getBufferSize(), bufferSizeMs,
-            elapsedSinceLastFeedMs);
-      }
     }
 
     int handleBufferResult;
     try {
       handleBufferResult = audioTrack.handleBuffer(buffer, bufferPresentationTimeUs);
-      lastFeedElapsedRealtimeMs = SystemClock.elapsedRealtime();
     } catch (AudioTrack.WriteException e) {
       throw ExoPlaybackException.createForRenderer(e, getIndex());
     }
@@ -408,4 +393,11 @@ public class MediaCodecAudioRenderer extends MediaCodecRenderer implements Media
     }
   }
 
+  // AudioTrack.Listener implementation.
+
+  @Override
+  public void onUnderrun(int bufferSize, long bufferSizeMs, long elapsedSinceLastFeedMs) {
+    eventDispatcher.audioTrackUnderrun(bufferSize, bufferSizeMs, elapsedSinceLastFeedMs);
+  }
+
 }

library/src/main/java/com/google/android/exoplayer2/audio/SimpleDecoderAudioRenderer.java

@@ -41,7 +41,8 @@ import com.google.android.exoplayer2.util.Util;
 /**
  * Decodes and renders audio using a {@link SimpleDecoder}.
  */
-public abstract class SimpleDecoderAudioRenderer extends BaseRenderer implements MediaClock {
+public abstract class SimpleDecoderAudioRenderer extends BaseRenderer implements MediaClock,
+    AudioTrack.Listener {
 
   private final boolean playClearSamplesWithoutKeys;
 
@@ -67,9 +68,6 @@ public abstract class SimpleDecoderAudioRenderer extends BaseRenderer implements
   private final AudioTrack audioTrack;
   private int audioSessionId;
 
-  private boolean audioTrackHasData;
-  private long lastFeedElapsedRealtimeMs;
-
   public SimpleDecoderAudioRenderer() {
     this(null, null);
   }
@@ -122,7 +120,7 @@ public abstract class SimpleDecoderAudioRenderer extends BaseRenderer implements
     this.playClearSamplesWithoutKeys = playClearSamplesWithoutKeys;
     eventDispatcher = new EventDispatcher(eventHandler, eventListener);
     audioSessionId = AudioTrack.SESSION_ID_NOT_SET;
-    audioTrack = new AudioTrack(audioCapabilities, streamType);
+    audioTrack = new AudioTrack(audioCapabilities, streamType, this);
     formatHolder = new FormatHolder();
   }
 
@@ -245,24 +243,12 @@ public abstract class SimpleDecoderAudioRenderer extends BaseRenderer implements
       } else {
         audioTrack.initialize(audioSessionId);
       }
-      audioTrackHasData = false;
       if (getState() == STATE_STARTED) {
         audioTrack.play();
       }
-    } else {
-      // Check for AudioTrack underrun.
-      boolean audioTrackHadData = audioTrackHasData;
-      audioTrackHasData = audioTrack.hasPendingData();
-      if (audioTrackHadData && !audioTrackHasData && getState() == STATE_STARTED) {
-        long elapsedSinceLastFeedMs = SystemClock.elapsedRealtime() - lastFeedElapsedRealtimeMs;
-        long bufferSizeMs = C.usToMs(audioTrack.getBufferSizeUs());
-        eventDispatcher.audioTrackUnderrun(audioTrack.getBufferSize(), bufferSizeMs,
-            elapsedSinceLastFeedMs);
-      }
     }
 
     int handleBufferResult = audioTrack.handleBuffer(outputBuffer.data, outputBuffer.timeUs);
-    lastFeedElapsedRealtimeMs = SystemClock.elapsedRealtime();
 
     // If we are out of sync, allow currentPositionUs to jump backwards.
     if ((handleBufferResult & AudioTrack.RESULT_POSITION_DISCONTINUITY) != 0) {
@@ -493,4 +479,11 @@ public abstract class SimpleDecoderAudioRenderer extends BaseRenderer implements
     }
   }
 
+  // AudioTrack.Listener implementation.
+
+  @Override
+  public void onUnderrun(int bufferSize, long bufferSizeMs, long elapsedSinceLastFeedMs) {
+    eventDispatcher.audioTrackUnderrun(bufferSize, bufferSizeMs, elapsedSinceLastFeedMs);
+  }
+
 }