MediaResource refactoring to support multiple streams

media/filters/ffmpeg_demuxer.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "media/filters/ffmpeg_demuxer.h"
 
 #include <algorithm>
 #include <memory>
 #include <set>
 #include <utility>
@@ skipping 1008 matching lines @@
                  ConvertToTimeBase(seeking_stream->time_base, seek_time),
                  // Always seek to a timestamp <= to the desired timestamp.
                  AVSEEK_FLAG_BACKWARD),
       base::Bind(&FFmpegDemuxer::OnSeekFrameDone, weak_factory_.GetWeakPtr()));
 }
 
 base::Time FFmpegDemuxer::GetTimelineOffset() const {
   return timeline_offset_;
 }
 
-DemuxerStream* FFmpegDemuxer::GetStream(DemuxerStream::Type type) {
+std::vector<DemuxerStream*> FFmpegDemuxer::GetStreams() {
   DCHECK(task_runner_->BelongsToCurrentThread());
-  return GetFFmpegStream(type);
+  std::vector<DemuxerStream*> result;
+  for (const auto& stream : streams_) {
+    if (stream)

[tguilbert, 2017/01/24 23:24:40]

Can there ever be null streams?

[servolk, 2017/01/25 00:57:32]

Yes. Streams with unsupported audio/video codecs or unsupported stream types
will be null in the |FFmpegDemuxer::streams_| array, see
FFmpegDemuxer::OnFindStreamInfoDone.

+      result.push_back(stream.get());
+  }
+  return result;
 }
 
 FFmpegDemuxerStream* FFmpegDemuxer::GetFFmpegStream(

[tguilbert, 2017/01/24 23:24:40]

Should this be renamed to "GetFirstEnabledStream"? There are only 3 callsites,
so this might not be necessary.

[servolk, 2017/01/25 00:57:32]

Thanks for drawing my attention to this. I've fixed the GetBufferedRanges
implementation to handle multi-track cases correctly and that removed two of
those 3 call sites. As to the remaining one, it's not immediately clear to me if
we also need to change logic there to take into account that we might have
multiple audio tracks.
How about renaming this into GetFirstEnabledFFStream to emphasize the fact that
this returns FFmpeg stream pointer, and not a generic DemuxerStream pointer?

[tguilbert, 2017/01/25 02:36:46]

That name seems good to me.

     DemuxerStream::Type type) const {
   for (const auto& stream : streams_) {
     if (stream && stream->type() == type && stream->enabled()) {
       return stream.get();
     }
   }
   return NULL;
 }
 
 base::TimeDelta FFmpegDemuxer::GetStartTime() const {
@@ skipping 763 matching lines @@
 
 void FFmpegDemuxer::SetLiveness(DemuxerStream::Liveness liveness) {
   DCHECK(task_runner_->BelongsToCurrentThread());
   for (const auto& stream : streams_) {
     if (stream)
       stream->SetLiveness(liveness);
   }
 }
 
 }  // namespace media