MSE: Relax the 'media segment must begin with keyframe' requirement

media/filters/frame_processor.cc

Index: media/filters/frame_processor.cc
diff --git a/media/filters/frame_processor.cc b/media/filters/frame_processor.cc
index e77e452fd8e184f0b5a8b06cad657afd9e5ff8a9..a648c1d1d7b72dfb7643684569cc3bb128139beb 100644
--- a/media/filters/frame_processor.cc
+++ b/media/filters/frame_processor.cc
@@ -161,6 +161,7 @@ bool MseTrackBuffer::FlushProcessedFrames() {
 FrameProcessor::FrameProcessor(const UpdateDurationCB& update_duration_cb,
                                const scoped_refptr<MediaLog>& media_log)
     : group_start_timestamp_(kNoTimestamp()),
+      last_processed_decode_timestamp_(kNoDecodeTimestamp()),
       update_duration_cb_(update_duration_cb),
       media_log_(media_log) {
   DVLOG(2) << __FUNCTION__ << "()";
@@ -194,7 +195,6 @@ bool FrameProcessor::ProcessFrames(
     const StreamParser::TextBufferQueueMap& text_map,
     base::TimeDelta append_window_start,
     base::TimeDelta append_window_end,
-    bool* new_media_segment,
     base::TimeDelta* timestamp_offset) {
   StreamParser::BufferQueue frames;
   if (!MergeBufferQueues(audio_buffers, video_buffers, text_map, &frames)) {
@@ -214,7 +214,7 @@ bool FrameProcessor::ProcessFrames(
   for (StreamParser::BufferQueue::const_iterator frames_itr = frames.begin();
        frames_itr != frames.end(); ++frames_itr) {
     if (!ProcessFrame(*frames_itr, append_window_start, append_window_end,
-                      timestamp_offset, new_media_segment)) {
+                      timestamp_offset)) {
       FlushProcessedFrames();
       return false;
     }
@@ -287,6 +287,10 @@ void FrameProcessor::Reset() {
        itr != track_buffers_.end(); ++itr) {
     itr->second->Reset();
   }
+
+  last_processed_decode_timestamp_ = kNoDecodeTimestamp();
+  in_coded_frame_group_ =
+      false;  // BIG TODO: Does this need to be conditioned on appendMode?
 }
 
 void FrameProcessor::OnPossibleAudioConfigUpdate(
@@ -312,14 +316,14 @@ MseTrackBuffer* FrameProcessor::FindTrack(StreamParser::TrackId id) {
   return itr->second;
 }
 
-void FrameProcessor::NotifyNewMediaSegmentStarting(
-    DecodeTimestamp segment_timestamp) {
-  DVLOG(2) << __FUNCTION__ << "(" << segment_timestamp.InSecondsF() << ")";
+void FrameProcessor::NotifyStartOfCodedFrameGroup(
+    DecodeTimestamp start_timestamp) {
+  DVLOG(2) << __FUNCTION__ << "(" << start_timestamp.InSecondsF() << ")";
 
   for (TrackBufferMap::iterator itr = track_buffers_.begin();
        itr != track_buffers_.end();
        ++itr) {
-    itr->second->stream()->OnNewMediaSegment(segment_timestamp);
+    itr->second->stream()->OnStartOfCodedFrameGroup(start_timestamp);
   }
 }
 
@@ -440,8 +444,7 @@ bool FrameProcessor::ProcessFrame(
     const scoped_refptr<StreamParserBuffer>& frame,
     base::TimeDelta append_window_start,
     base::TimeDelta append_window_end,
-    base::TimeDelta* timestamp_offset,
-    bool* new_media_segment) {
+    base::TimeDelta* timestamp_offset) {
   // Implements the loop within step 1 of the coded frame processing algorithm
   // for a single input frame per April 1, 2014 MSE spec editor's draft:
   // https://dvcs.w3.org/hg/html-media/raw-file/d471a4412040/media-source/
@@ -581,6 +584,10 @@ bool FrameProcessor::ProcessFrame(
     //    times last frame duration:
     DecodeTimestamp last_decode_timestamp =
         track_buffer->last_decode_timestamp();
+    // BIG TODO: continue here, using last_processed_decode_timestamp_. And
+    // conditionally resetting in_coded_frame_group_. And investigating how
+    // common single-stream-cluster appends are in mp4 or other muxed byte
+    // stream formats.
     if (last_decode_timestamp != kNoDecodeTimestamp()) {
       base::TimeDelta dts_delta = decode_timestamp - last_decode_timestamp;
       if (dts_delta < base::TimeDelta() ||
@@ -593,8 +600,8 @@ bool FrameProcessor::ProcessFrame(
           group_end_timestamp_ = presentation_timestamp;
           // This triggers a discontinuity so we need to treat the next frames
           // appended within the append window as if they were the beginning of
-          // a new segment.
-          *new_media_segment = true;
+          // a new coded frame group.
+          in_coded_frame_group_ = false;
         } else {
           DVLOG(3) << __FUNCTION__ << " : Sequence mode discontinuity, GETS: "
                    << group_end_timestamp_.InSecondsF();
@@ -684,19 +691,19 @@ bool FrameProcessor::ProcessFrame(
     }
 
     // We now have a processed buffer to append to the track buffer's stream.
-    // If it is the first in a new media segment or following a discontinuity,
-    // notify all the track buffers' streams that a new segment is beginning.
-    if (*new_media_segment) {
-      // First, complete the append to track buffer streams of previous media
-      // segment's frames, if any.
+    // If it is the first in a new coded frame group (such as following a
+    // discontinuity), notify all the track buffers' streams that a coded frame
+    // group is starting.
+    if (!in_coded_frame_group_) {
+      // First, complete the append to track buffer streams of the previous
+      // coded frame group's frames, if any.
       if (!FlushProcessedFrames())
         return false;
 
-      *new_media_segment = false;
-
       // TODO(acolwell/wolenetz): This should be changed to a presentation
       // timestamp. See http://crbug.com/402502
-      NotifyNewMediaSegmentStarting(decode_timestamp);
+      NotifyStartOfCodedFrameGroup(decode_timestamp);
+      in_coded_frame_group_ = true;
     }
 
     DVLOG(3) << __FUNCTION__ << ": Sending processed frame to stream, "
@@ -705,7 +712,7 @@ bool FrameProcessor::ProcessFrame(
 
     // Steps 13-18: Note, we optimize by appending groups of contiguous
     // processed frames for each track buffer at end of ProcessFrames() or prior
-    // to NotifyNewMediaSegmentStarting().
+    // to NotifyStartOfCodedFrameGroup().
     // TODO(wolenetz): Refactor SourceBufferStream to conform to spec GC timing.
     // See http://crbug.com/371197.
     track_buffer->EnqueueProcessedFrame(frame);