Fix an issue that audio and video may run out of sync

media/base/android/java/src/org/chromium/media/MediaCodecBridge.java

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 package org.chromium.media;
 
 import android.media.AudioFormat;
 import android.media.AudioManager;
 import android.media.AudioTrack;
 import android.media.MediaCodec;
@@ skipping 262 matching lines @@
             Log.e(TAG, "Failed to dequeue input buffer", e);
         }
         return new DequeueInputResult(status, index);
     }
 
     @CalledByNative
     private int flush() {
         try {
             mFlushed = true;
             if (mAudioTrack != null) {
+                // Need to call pause() here, or otherwise flush() is a no-op.
+                mAudioTrack.pause();
                 mAudioTrack.flush();
             }
             mMediaCodec.flush();
         } catch (IllegalStateException e) {
             Log.e(TAG, "Failed to flush MediaCodec", e);
             return MEDIA_CODEC_ERROR;
         }
         return MEDIA_CODEC_OK;
     }
 
@@ skipping 220 matching lines @@
                     return false;
                 }
             }
             return true;
         } catch (IllegalStateException e) {
             Log.e(TAG, "Cannot configure the audio codec", e);
         }
         return false;
     }
 
+    /**
+     *  Play the audio buffer that is passed in.
+     *
+     *  @param buf Audio buffer to be rendered.
+     *  @return The number of frames that have already been consumed by the
+     *  hardware. This number resets to 0 after each flush call.
+     */
     @CalledByNative
-    private void playOutputBuffer(byte[] buf) {
+    private long playOutputBuffer(byte[] buf) {
         if (mAudioTrack != null) {
             if (AudioTrack.PLAYSTATE_PLAYING != mAudioTrack.getPlayState()) {
                 mAudioTrack.play();
             }
             int size = mAudioTrack.write(buf, 0, buf.length);
             if (buf.length != size) {
                 Log.i(TAG, "Failed to send all data to audio output, expected size: " +
                         buf.length + ", actual size: " + size);
             }
+            // TODO(qinmin): Returning the head position allows us to estimate
+            // the current presentation time in native code. However, it is
+            // better to use AudioTrack.getCurrentTimestamp() to get the last
+            // known time when a frame is played. However, we will need to
+            // convert the java nano time to C++ timestamp.
+            // If the stream runs too long, getPlaybackHeadPosition() could
+            // overflow. AudioTimestampHelper in MediaSourcePlayer has the same
+            // issue. See http://crbug.com/358801.
+            return mAudioTrack.getPlaybackHeadPosition();
         }
+        return 0;
     }
 
     @CalledByNative
     private void setVolume(double volume) {
         if (mAudioTrack != null) {
             mAudioTrack.setStereoVolume((float) volume, (float) volume);
         }
     }
 
     private void resetLastPresentationTimeIfNeeded(long presentationTimeUs) {
@@ skipping 14 matching lines @@
                 return AudioFormat.CHANNEL_OUT_QUAD;
             case 6:
                 return AudioFormat.CHANNEL_OUT_5POINT1;
             case 8:
                 return AudioFormat.CHANNEL_OUT_7POINT1;
             default:
                 return AudioFormat.CHANNEL_OUT_DEFAULT;
         }
     }
 }