Add flag to force spurious audio timestamps to fail playback.

For enabling during device test runs.

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

@@ -55,7 +55,7 @@ public final class AudioTrack {
   /**
    * Thrown when a failure occurs instantiating an {@link android.media.AudioTrack}.
    */
-  public static class InitializationException extends Exception {
+  public static final class InitializationException extends Exception {
 
     /** The state as reported by {@link android.media.AudioTrack#getState()}. */
     public final int audioTrackState;
@@ -72,7 +72,7 @@ public final class AudioTrack {
   /**
    * Thrown when a failure occurs writing to an {@link android.media.AudioTrack}.
    */
-  public static class WriteException extends Exception {
+  public static final class WriteException extends Exception {
 
     /** The value returned from {@link android.media.AudioTrack#write(byte[], int, int)}. */
     public final int errorCode;
@@ -84,6 +84,18 @@ public final class AudioTrack {
 
   }
 
+  /**
+   * Thrown when {@link android.media.AudioTrack#getTimestamp} returns a spurious timestamp, if
+   * {@code AudioTrack#failOnSpuriousAudioTimestamp} is set.
+   */
+  private static final class InvalidAudioTrackTimestampException extends RuntimeException {
+
+    public InvalidAudioTrackTimestampException(String message) {
+      super(message);
+    }
+
+  }
+
   /** Returned in the result of {@link #handleBuffer} if the buffer was discontinuous. */
   public static final int RESULT_POSITION_DISCONTINUITY = 1;
   /** Returned in the result of {@link #handleBuffer} if the buffer can be released. */
@@ -134,12 +146,22 @@ public final class AudioTrack {
   private static final int MIN_TIMESTAMP_SAMPLE_INTERVAL_US = 500000;
 
   /**
-   * Set to {@code true} to enable a workaround for an issue where an audio effect does not keep its
-   * session active across releasing/initializing a new audio track, on platform API version < 21.
-   * The flag must be set before creating the player.
+   * Whether to enable a workaround for an issue where an audio effect does not keep its session
+   * active across releasing/initializing a new audio track, on platform API version < 21.
+   * <p>
+   * The flag must be set before creating a player.
    */
   public static boolean enablePreV21AudioSessionWorkaround = false;
 
+  /**
+   * Whether to throw an {@link InvalidAudioTrackTimestampException} when a spurious timestamp is
+   * reported from {@link android.media.AudioTrack#getTimestamp}.
+   * <p>
+   * The flag must be set before creating a player. Should be set to {@code true} for testing and
+   * debugging purposes only.
+   */
+  public static boolean failOnSpuriousAudioTimestamp = false;
+
   private final ConditionVariable releasingConditionVariable;
   private final long[] playheadOffsets;
   private final AudioTrackUtil audioTrackUtil;
@@ -626,7 +648,9 @@ public final class AudioTrack {
     return isInitialized() && startMediaTimeState != START_NOT_SET;
   }
 
-  /** Updates the audio track latency and playback position parameters. */
+  /**
+   * Updates the audio track latency and playback position parameters.
+   */
   private void maybeSampleSyncParams() {
     long playbackPositionUs = audioTrackUtil.getPlaybackHeadPositionUs();
     if (playbackPositionUs == 0) {
@@ -661,17 +685,25 @@ public final class AudioTrack {
           audioTimestampSet = false;
         } else if (Math.abs(audioTimestampUs - systemClockUs) > MAX_AUDIO_TIMESTAMP_OFFSET_US) {
           // The timestamp time base is probably wrong.
-          audioTimestampSet = false;
-          Log.w(TAG, "Spurious audio timestamp (system clock mismatch): "
+          String message = "Spurious audio timestamp (system clock mismatch): "
               + audioTimestampFramePosition + ", " + audioTimestampUs + ", " + systemClockUs + ", "
-              + playbackPositionUs);
+              + playbackPositionUs;
+          if (failOnSpuriousAudioTimestamp) {
+            throw new InvalidAudioTrackTimestampException(message);
+          }
+          Log.w(TAG, message);
+          audioTimestampSet = false;
         } else if (Math.abs(framesToDurationUs(audioTimestampFramePosition) - playbackPositionUs)
             > MAX_AUDIO_TIMESTAMP_OFFSET_US) {
           // The timestamp frame position is probably wrong.
-          audioTimestampSet = false;
-          Log.w(TAG, "Spurious audio timestamp (frame position mismatch): "
+          String message = "Spurious audio timestamp (frame position mismatch): "
               + audioTimestampFramePosition + ", " + audioTimestampUs + ", " + systemClockUs + ", "
-              + playbackPositionUs);
+              + playbackPositionUs;
+          if (failOnSpuriousAudioTimestamp) {
+            throw new InvalidAudioTrackTimestampException(message);
+          }
+          Log.w(TAG, message);
+          audioTimestampSet = false;
         }
       }
       if (getLatencyMethod != null) {