Bug 1230338 - Record video frames dropped by the compositor, or while flushing during skip-to-keyframe. r=jya

dom/media/MediaFormatReader.cpp

@@ -510,6 +510,14 @@ MediaFormatReader::RequestVideoData(bool aSkipToNextKeyframe,
   if (ShouldSkip(aSkipToNextKeyframe, timeThreshold)) {
     // Cancel any pending demux request.
     mVideo.mDemuxRequest.DisconnectIfExists();
+
+    // I think it's still possible for an output to have been sent from the decoder
+    // and is currently sitting in our event queue waiting to be processed. The following
+    // flush won't clear it, and when we return to the event loop it'll be added to our
+    // output queue and be used.
+    // This code will count that as dropped, which was the intent, but not quite true.
+    mDecoder->NotifyDecodedFrames(0, 0, SizeOfVideoQueueInFrames());
+
     Flush(TrackInfo::kVideoTrack);
     RefPtr<VideoDataPromise> p = mVideo.mPromise.Ensure(__func__);
     SkipVideoDemuxToNextKeyFrame(timeThreshold);

dom/media/VideoFrameContainer.h

@@ -78,6 +78,8 @@ public:
   B2G_ACL_EXPORT ImageContainer* GetImageContainer();
   void ForgetElement() { mElement = nullptr; }
 
+  uint32_t GetDroppedImageCount() { return mImageContainer->GetDroppedImageCount(); }
+
 protected:
   void SetCurrentFramesLocked(const gfx::IntSize& aIntrinsicSize,
                               const nsTArray<ImageContainer::NonOwningImage>& aImages);

dom/media/mediasink/VideoSink.cpp

@@ -35,6 +35,7 @@ VideoSink::VideoSink(AbstractThread* aThread,
   , mRealTime(aRealTime)
   , mFrameStats(aFrameStats)
   , mVideoFrameEndTime(-1)
+  , mOldDroppedCount(0)
   , mHasVideo(false)
   , mUpdateScheduler(aThread)
   , mVideoQueueSendToCompositorSize(aVQueueSentToCompositerSize)
@@ -327,6 +328,10 @@ VideoSink::RenderVideoFrames(int32_t aMaxFrames,
                 frame->mTime, frame->mFrameID, VideoQueue().GetSize());
   }
   mContainer->SetCurrentFrames(frames[0]->As<VideoData>()->mDisplay, images);
+
+  uint32_t dropped = mContainer->GetDroppedImageCount();
+  mFrameStats.NotifyDecodedFrames(0, 0, dropped - mOldDroppedCount);
+  mOldDroppedCount = dropped;
 }
 
 void

dom/media/mediasink/VideoSink.h

@@ -129,6 +129,8 @@ private:
   // in microseconds.
   int64_t mVideoFrameEndTime;
 
+  uint32_t mOldDroppedCount;
+
   // Event listeners for VideoQueue
   MediaEventListener mPushListener;