Bug 816664: wallpaper patch for negative delta times for video frames r=derf

content/media/MediaSegment.h

@@ -215,6 +215,7 @@ protected:
   void AppendFromInternal(MediaSegmentBase<C, Chunk>* aSource)
   {
     static_cast<C*>(this)->CheckCompatible(*static_cast<C*>(aSource));
+    MOZ_ASSERT(aSource->mDuration >= 0);
     mDuration += aSource->mDuration;
     aSource->mDuration = 0;
     if (!mChunks.IsEmpty() && !aSource->mChunks.IsEmpty() &&
@@ -248,6 +249,7 @@ protected:
 
   Chunk* AppendChunk(TrackTicks aDuration)
   {
+    MOZ_ASSERT(aDuration >= 0);
     Chunk* c = mChunks.AppendElement();
     c->mDuration = aDuration;
     mDuration += aDuration;

content/media/webrtc/MediaEngineWebRTCAudio.cpp

@@ -146,7 +146,7 @@ MediaEngineWebRTCAudioSource::NotifyPull(MediaStreamGraph* aGraph,
   static TrackTicks mLastEndTime = 0;
   TrackTicks target = TimeToTicksRoundUp(SAMPLE_FREQUENCY, aDesiredTime);
   TrackTicks delta = target - mLastEndTime;
-  LOG(("Audio:NotifyPull: target %lu, delta %lu",(uint32_t) target, (uint32_t) delta));
+  LOG(("Audio: NotifyPull: aDesiredTime %ld, target %ld, delta %ld",(int64_t) aDesiredTime, (int64_t) target, (int64_t) delta));
   mLastEndTime = target;
 #endif
 }

content/media/webrtc/MediaEngineWebRTCVideo.cpp

@@ -15,6 +15,7 @@ extern PRLogModuleInfo* GetMediaManagerLog();
 #else
 #define LOG(msg)
 #endif
+#define LOG_ALL_FRAMES 1
 
 /**
  * Webrtc video source.
@@ -110,12 +111,16 @@ MediaEngineWebRTCVideoSource::NotifyPull(MediaStreamGraph* aGraph,
   TrackTicks target = TimeToTicksRoundUp(USECS_PER_S, aDesiredTime);
   TrackTicks delta = target - mLastEndTime;
 #ifdef LOG_ALL_FRAMES
-  LOG(("NotifyPull, target = %lu, delta = %lu", (uint64_t) target, (uint64_t) delta));
+  LOG(("NotifyPull, desired = %ld, target = %ld, delta = %ld", (int64_t) aDesiredTime, (int64_t) target, (int64_t) delta));
 #endif
-  // NULL images are allowed
-  segment.AppendFrame(image ? image.forget() : nullptr, delta, gfxIntSize(mWidth, mHeight));
-  mSource->AppendToTrack(mTrackID, &(segment));
-  mLastEndTime = target;
+  // Don't append if we've already provided a frame that supposedly goes past the current aDesiredTime
+  // Doing so means a negative delta and thus messes up handling of the graph
+  if (delta > 0) {
+    // NULL images are allowed
+    segment.AppendFrame(image ? image.forget() : nullptr, delta, gfxIntSize(mWidth, mHeight));
+    mSource->AppendToTrack(mTrackID, &(segment));
+    mLastEndTime = target;
+  }
 }
 
 void