MediaCodecPlayer implementation (stage 4 - preroll)

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

Index: media/base/android/java/src/org/chromium/media/MediaCodecBridge.java
diff --git a/media/base/android/java/src/org/chromium/media/MediaCodecBridge.java b/media/base/android/java/src/org/chromium/media/MediaCodecBridge.java
index 0433a471ab7761edb371034623150fee010660fd..c9ae5ce9fcf30e13e5e9018f0521f42cee651289 100644
--- a/media/base/android/java/src/org/chromium/media/MediaCodecBridge.java
+++ b/media/base/android/java/src/org/chromium/media/MediaCodecBridge.java
@@ -74,6 +74,7 @@ class MediaCodecBridge {
 
     private MediaCodec mMediaCodec;
     private AudioTrack mAudioTrack;
+    private byte[] mPendingAudioBuffer;
     private boolean mFlushed;
     private long mLastPresentationTimeUs;
     private String mMime;
@@ -302,6 +303,7 @@ class MediaCodecBridge {
             MediaCodec mediaCodec, String mime, boolean adaptivePlaybackSupported) {
         assert mediaCodec != null;
         mMediaCodec = mediaCodec;
+        mPendingAudioBuffer = null;
         mMime = mime;
         mLastPresentationTimeUs = 0;
         mFlushed = true;
@@ -366,6 +368,7 @@ class MediaCodecBridge {
         if (mAudioTrack != null) {
             mAudioTrack.release();
         }
+        mPendingAudioBuffer = null;
     }
 
     @SuppressWarnings("deprecation")
@@ -413,6 +416,7 @@ class MediaCodecBridge {
                 // Need to call pause() here, or otherwise flush() is a no-op.
                 mAudioTrack.pause();
                 mAudioTrack.flush();
+                mPendingAudioBuffer = null;
             }
             mMediaCodec.flush();
         } catch (IllegalStateException e) {
@@ -726,7 +730,14 @@ class MediaCodecBridge {
      *  hardware. This number resets to 0 after each flush call.
      */
     @CalledByNative
-    private long playOutputBuffer(byte[] buf) {
+    private long playOutputBuffer(byte[] buf, boolean postpone) {
+        if (postpone) {
+            Log.v(TAG, "Saving pending buffer");

[wolenetz, 2015/08/20 20:37:36]

nit: Is Log.v too spammy/verbose? I defer to qinmin@ on this (and same in the
other Log.v, below).

[Tima Vaisburd, 2015/08/20 22:36:36]

I agree, deleted the two Log.v() lines.

+            assert mPendingAudioBuffer == null;

[wolenetz, 2015/08/20 20:37:36]

What protects (including any bridge java or .h method documentation) this assert
from firing? For instance, what if mAudioTrack is null the first time and
postpone was incorrectly set true by caller on the second time.. Then this
assert would fire.

[Tima Vaisburd, 2015/08/20 22:36:36]

I added the documentation. Only the convention that there should be no more than
one postponed buffer in a row. The assert is intended to check this convention.

+            mPendingAudioBuffer = buf;
+            return 0;
+        }
+
         if (mAudioTrack == null) {

[wolenetz, 2015/08/20 20:37:36]

Is there really a case where we should allow caching buf for postponed playback,
yet mAudioTrack is null? IOW, should this early-return check be moved prior to
the "if (postpone)", above?

[Tima Vaisburd, 2015/08/20 22:36:36]

Done. I agree that mAudioTrack check is better be moved up to preserve the
behavior that we skip the buffers if audio is not configured.

             return 0;
         }
@@ -734,7 +745,19 @@ class MediaCodecBridge {
         if (AudioTrack.PLAYSTATE_PLAYING != mAudioTrack.getPlayState()) {
             mAudioTrack.play();
         }
-        int size = mAudioTrack.write(buf, 0, buf.length);
+
+        int size = 0;
+        if (mPendingAudioBuffer != null) {
+            Log.v(TAG, "Writing pending buffer");
+            size = mAudioTrack.write(mPendingAudioBuffer, 0, mPendingAudioBuffer.length);
+            if (mPendingAudioBuffer.length != size) {
+                Log.i(TAG, "Failed to send all data to audio output, expected size: "
+                                + mPendingAudioBuffer.length + ", actual size: " + size);
+            }
+            mPendingAudioBuffer = null;
+        }
+
+        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);