Bug 1172830 - Move buffering check out of MediaDecoderStateMachine::UpdateRenderedVideoFrames(). r=cpearce.

dom/media/MediaDecoderStateMachine.cpp

@@ -699,6 +699,7 @@ MediaDecoderStateMachine::OnAudioPopped(const nsRefPtr<MediaData>& aSample)
   mPlaybackOffset = std::max(mPlaybackOffset.Ref(), aSample->mOffset);
   UpdateNextFrameStatus();
   DispatchAudioDecodeTaskIfNeeded();
+  MaybeStartBuffering();
 }
 
 void
@@ -709,6 +710,7 @@ MediaDecoderStateMachine::OnVideoPopped(const nsRefPtr<MediaData>& aSample)
   mPlaybackOffset = std::max(mPlaybackOffset.Ref(), aSample->mOffset);
   UpdateNextFrameStatus();
   DispatchVideoDecodeTaskIfNeeded();
+  MaybeStartBuffering();
 }
 
 void
@@ -1097,6 +1099,34 @@ void MediaDecoderStateMachine::MaybeStartPlayback()
   DispatchDecodeTasksIfNeeded();
 }
 
+void
+MediaDecoderStateMachine::MaybeStartBuffering()
+{
+  MOZ_ASSERT(OnTaskQueue());
+  AssertCurrentThreadInMonitor();
+
+  if (mState == DECODER_STATE_DECODING &&
+      mPlayState == MediaDecoder::PLAY_STATE_PLAYING &&
+      mResource->IsExpectingMoreData()) {
+    bool shouldBuffer;
+    if (mReader->UseBufferingHeuristics()) {
+      shouldBuffer = HasLowDecodedData(EXHAUSTED_DATA_MARGIN_USECS) &&
+                     (JustExitedQuickBuffering() || HasLowUndecodedData());
+    } else {
+      MOZ_ASSERT(mReader->IsWaitForDataSupported());
+      shouldBuffer = (OutOfDecodedAudio() && mAudioWaitRequest.Exists()) ||
+                     (OutOfDecodedVideo() && mVideoWaitRequest.Exists());
+    }
+    if (shouldBuffer) {
+      StartBuffering();
+      // Don't go straight back to the state machine loop since that might
+      // cause us to start decoding again and we could flip-flop between
+      // decoding and quick-buffering.
+      ScheduleStateMachineIn(USECS_PER_S);
+    }
+  }
+}
+
 void MediaDecoderStateMachine::UpdatePlaybackPositionInternal(int64_t aTime)
 {
   MOZ_ASSERT(OnTaskQueue());
@@ -2612,30 +2642,6 @@ void MediaDecoderStateMachine::UpdateRenderedVideoFrames()
 
   RenderVideoFrames(sVideoQueueSendToCompositorSize, clockTime, nowTime);
 
-  // Check to see if we don't have enough data to play up to the next frame.
-  // If we don't, switch to buffering mode.
-  if (mState == DECODER_STATE_DECODING &&
-      mPlayState == MediaDecoder::PLAY_STATE_PLAYING &&
-      mResource->IsExpectingMoreData()) {
-    bool shouldBuffer;
-    if (mReader->UseBufferingHeuristics()) {
-      shouldBuffer = HasLowDecodedData(EXHAUSTED_DATA_MARGIN_USECS) &&
-                     (JustExitedQuickBuffering() || HasLowUndecodedData());
-    } else {
-      MOZ_ASSERT(mReader->IsWaitForDataSupported());
-      shouldBuffer = (OutOfDecodedAudio() && mAudioWaitRequest.Exists()) ||
-                     (OutOfDecodedVideo() && mVideoWaitRequest.Exists());
-    }
-    if (shouldBuffer) {
-      StartBuffering();
-      // Don't go straight back to the state machine loop since that might
-      // cause us to start decoding again and we could flip-flop between
-      // decoding and quick-buffering.
-      ScheduleStateMachineIn(USECS_PER_S);
-      return;
-    }
-  }
-
   // Cap the current time to the larger of the audio and video end time.
   // This ensures that if we're running off the system clock, we don't
   // advance the clock to after the media end time.

dom/media/MediaDecoderStateMachine.h

@@ -522,6 +522,10 @@ protected:
   // Must be called with the decode monitor held.
   void MaybeStartPlayback();
 
+  // Check to see if we don't have enough data to play up to the next frame.
+  // If we don't, switch to buffering mode.
+  void MaybeStartBuffering();
+
   // Moves the decoder into decoding state. Called on the state machine
   // thread. The decoder monitor must be held.
   void StartDecoding();