Fix MSE GC, make it less aggressive, more spec-compliant

media/filters/chunk_demuxer.cc

Index: media/filters/chunk_demuxer.cc
diff --git a/media/filters/chunk_demuxer.cc b/media/filters/chunk_demuxer.cc
index 51511c8f69ad9dff37773d5d147c54b993211786..4faafac88f2614552086c2dfe36c7491f8d4a33c 100644
--- a/media/filters/chunk_demuxer.cc
+++ b/media/filters/chunk_demuxer.cc
@@ -131,6 +131,14 @@ class SourceState {
   // ChunkDemuxerStreams managed by this object.
   void Remove(TimeDelta start, TimeDelta end, TimeDelta duration);
 
+  // Attempts to perform garbage collection in SourceBuffers associated with

[wolenetz, 2015/08/12 21:09:57]

This comment seems ChunkDemuxer-focused. Move it to
ChunkDemuxer::EvictCodedFrames in the .h?

[servolk, 2015/08/13 00:31:42]

Will do

[servolk, 2015/08/20 02:45:27]

Done.

+  // this ChunkDemuxer. Returns true if garbage collection was successful.
+  // |media_time| parameter should indicate the current playback position.
+  // If it's a valid time value, the garbage collection algorithm will make sure
+  // to preserve unconsumed data buffers in the range between last read position
+  // and the current playback position.
+  bool EvictCodedFrames(DecodeTimestamp media_time);
+
   // Returns true if currently parsing a media segment, or false otherwise.
   bool parsing_media_segment() const { return parsing_media_segment_; }
 
@@ -369,6 +377,23 @@ void SourceState::Remove(TimeDelta start, TimeDelta end, TimeDelta duration) {
   }
 }
 
+bool SourceState::EvictCodedFrames(DecodeTimestamp media_time) {
+  bool success = true;
+
+  if (audio_)
+    success = audio_->EvictCodedFrames(media_time) && success;
+
+  if (video_)
+    success = video_->EvictCodedFrames(media_time) && success;
+
+  for (TextStreamMap::iterator itr = text_stream_map_.begin();
+       itr != text_stream_map_.end(); ++itr) {
+    success = itr->second->EvictCodedFrames(media_time) && success;
+  }
+
+  return success;
+}
+
 Ranges<TimeDelta> SourceState::GetBufferedRanges(TimeDelta duration,
                                                  bool ended) const {
   // TODO(acolwell): When we start allowing disabled tracks we'll need to update
@@ -879,6 +904,11 @@ void ChunkDemuxerStream::Remove(TimeDelta start, TimeDelta end,
   stream_->Remove(start, end, duration);
 }
 
+bool ChunkDemuxerStream::EvictCodedFrames(DecodeTimestamp media_time) {
+  base::AutoLock auto_lock(lock_);
+  return stream_->GarbageCollectIfNeeded(media_time);
+}
+
 void ChunkDemuxerStream::OnSetDuration(TimeDelta duration) {
   base::AutoLock auto_lock(lock_);
   stream_->OnSetDuration(duration);
@@ -1321,6 +1351,24 @@ Ranges<TimeDelta> ChunkDemuxer::GetBufferedRanges(const std::string& id) const {
   return itr->second->GetBufferedRanges(duration_, state_ == ENDED);
 }
 
+bool ChunkDemuxer::EvictCodedFrames(base::TimeDelta currentMediaTime) {
+  DVLOG(1) << __FUNCTION__ << " media_time=" << currentMediaTime.InSecondsF();
+  base::AutoLock auto_lock(lock_);
+
+  // Note: The direct conversion from PTS to DTS is safe here, since we don't
+  // need to know currentTime precisely for GC. GC only needs to know which GOP
+  // currentTime points to.
+  DecodeTimestamp media_time_dts =
+      DecodeTimestamp::FromPresentationTime(currentMediaTime);
+
+  bool success = true;
+  for (SourceStateMap::iterator itr = source_state_map_.begin();
+       itr != source_state_map_.end(); ++itr) {
+    success = itr->second->EvictCodedFrames(media_time_dts) && success;
+  }
+  return success;
+}
+
 void ChunkDemuxer::AppendData(
     const std::string& id,
     const uint8* data,