Bug 812756 - Set AmpleVideoFrames to the minimum to win a race when shutting down OMX.qcom.video.decoder.mpeg4 decoder r=doublec

content/media/MediaDecoderStateMachine.cpp

@@ -374,8 +374,8 @@ nsresult StateMachineTracker::RequestCreateDecodeThread(MediaDecoderStateMachine
 }
 
 MediaDecoderStateMachine::MediaDecoderStateMachine(MediaDecoder* aDecoder,
-                                                           MediaDecoderReader* aReader,
-                                                           bool aRealTime) :
+                                                   MediaDecoderReader* aReader,
+                                                   bool aRealTime) :
   mDecoder(aDecoder),
   mState(DECODER_STATE_DECODING_METADATA),
   mResetPlayStartTime(false),
@@ -759,7 +759,7 @@ bool MediaDecoderStateMachine::HaveEnoughDecodedVideo()
 {
   mDecoder->GetReentrantMonitor().AssertCurrentThreadIn();
 
-  if (static_cast<uint32_t>(mReader->VideoQueue().GetSize()) < mAmpleVideoFrames * mPlaybackRate) {
+  if (static_cast<uint32_t>(mReader->VideoQueue().GetSize()) < GetAmpleVideoFrames() * mPlaybackRate) {
     return false;
   }
 
@@ -795,7 +795,7 @@ void MediaDecoderStateMachine::DecodeLoop()
 
   // Once we've decoded more than videoPumpThreshold video frames, we'll
   // no longer be considered to be "pumping video".
-  const unsigned videoPumpThreshold = mRealTime ? 0 : mAmpleVideoFrames / 2;
+  const unsigned videoPumpThreshold = mRealTime ? 0 : GetAmpleVideoFrames() / 2;
 
   // After the audio decode fills with more than audioPumpThreshold usecs
   // of decoded audio, we'll start to check whether the audio or video decode

content/media/MediaDecoderStateMachine.h

@@ -322,6 +322,9 @@ public:
   // shutting down. The decoder monitor must be held while calling this.
   bool IsShutdown();
 
+protected:
+  virtual uint32_t GetAmpleVideoFrames() { return mAmpleVideoFrames; }
+
 private:
   class WakeDecoderRunnable : public nsRunnable {
   public:

content/media/omx/MediaOmxDecoder.cpp

@@ -6,7 +6,7 @@
 
 #include "MediaOmxDecoder.h"
 #include "MediaOmxReader.h"
-#include "MediaDecoderStateMachine.h"
+#include "MediaOmxStateMachine.h"
 
 namespace mozilla {
 
@@ -22,7 +22,7 @@ MediaDecoder* MediaOmxDecoder::Clone()
 
 MediaDecoderStateMachine* MediaOmxDecoder::CreateStateMachine()
 {
-  return new MediaDecoderStateMachine(this, new MediaOmxReader(this));
+  return new MediaOmxStateMachine(this, new MediaOmxReader(this));
 }
 
 MediaOmxDecoder::~MediaOmxDecoder()

content/media/omx/MediaOmxStateMachine.h

@@ -0,0 +1,27 @@
+#include "MediaDecoder.h"
+#include "MediaDecoderReader.h"
+#include "MediaDecoderStateMachine.h"
+
+namespace mozilla {
+
+class MediaOmxStateMachine : public MediaDecoderStateMachine
+{
+public:
+  MediaOmxStateMachine(MediaDecoder *aDecoder,
+                       MediaDecoderReader *aReader)
+    : MediaDecoderStateMachine(aDecoder, aReader) { }
+
+protected:
+  // Due to a bug in the OMX.qcom.video.decoder.mpeg4 decoder, we can't own too
+  // many video buffers before shutting down the decoder. When we release these
+  // buffers, they asynchronously signal to OMXCodec that we have returned
+  // ownership of the buffer.
+  // If this signal happens while the OMXCodec is shutting down, OMXCodec will
+  // crash. If the OMXCodec shuts down before all buffers are returned,
+  // OMXCodec will crash.
+  // So we need few enough buffers in the queue that all buffers will be
+  // returned before OMXCodec begins shutdown.
+  uint32_t GetAmpleVideoFrames() { return 2; }
+};
+
+} // namespace mozilla