Generate and assign media track ids in demuxers.

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 <utility>
 
@@ skipping 1100 matching lines @@
       packet_buffer = packet_buffer->next;
     }
   }
 
   std::unique_ptr<MediaTracks> media_tracks(new MediaTracks());
   AVStream* audio_stream = NULL;
   AudioDecoderConfig audio_config;
   AVStream* video_stream = NULL;
   VideoDecoderConfig video_config;
 
+  DCHECK(track_id_to_demux_stream_map_.empty());
+
   // If available, |start_time_| will be set to the lowest stream start time.
   start_time_ = kInfiniteDuration();
 
   base::TimeDelta max_duration;
   int detected_audio_track_count = 0;
   int detected_video_track_count = 0;
   int detected_text_track_count = 0;
   for (size_t i = 0; i < format_context->nb_streams; ++i) {
     AVStream* stream = format_context->streams[i];
     const AVCodecContext* codec_context = stream->codec;
@@ skipping 85 matching lines @@
         strstr(format_context->iformat->name, "matroska")) {
       // TODO(servolk): FFmpeg doesn't set stream->id correctly for webm files.
       // Need to fix that and use it as track id. crbug.com/323183
       track_id =
           static_cast<StreamParser::TrackId>(media_tracks->tracks().size() + 1);
       track_label = streams_[i]->GetMetadata("title");
     }
 
     // Note when we find our audio/video stream (we only want one of each) and
     // record src= playback UMA stats for the stream's decoder config.
+    MediaTrack* media_track = nullptr;
     if (codec_type == AVMEDIA_TYPE_AUDIO) {
       CHECK(!audio_stream);
       audio_stream = stream;
       audio_config = streams_[i]->audio_decoder_config();
       RecordAudioCodecStats(audio_config);
 
-      media_tracks->AddAudioTrack(audio_config, track_id, "main", track_label,
-                                  track_language);
+      media_track = media_tracks->AddAudioTrack(audio_config, track_id, "main",
+                                                track_label, track_language);
+      media_track->setId(base::UintToString(track_id));

[chcunningham, 2016/06/09 17:57:19]

So for src=, we re-use the bytstream track Id to set media track id. Should be
fine since the audio and video tracks should all have unique bytstream ids. I'd
add a CHECK (to catch bugs in ffmpeg or bugs in our assumptions) that you don't
already have the track id in the map before you add the new streams below.

[servolk, 2016/06/09 19:14:46]

Done. Only I've added a DCHECK, don't think it deserves a crash. We might be
able to continue normally by just overwriting the old id.

+      track_id_to_demux_stream_map_[media_track->id()] = streams_[i];
     } else if (codec_type == AVMEDIA_TYPE_VIDEO) {
       CHECK(!video_stream);
       video_stream = stream;
       video_config = streams_[i]->video_decoder_config();
       RecordVideoCodecStats(video_config, stream->codec->color_range);
 
-      media_tracks->AddVideoTrack(video_config, track_id, "main", track_label,
-                                  track_language);
+      media_track = media_tracks->AddVideoTrack(video_config, track_id, "main",
+                                                track_label, track_language);
+      media_track->setId(base::UintToString(track_id));
+      track_id_to_demux_stream_map_[media_track->id()] = streams_[i];
     }
 
     max_duration = std::max(max_duration, streams_[i]->duration());
 
     const base::TimeDelta start_time =
         ExtractStartTime(stream, start_time_estimates[i]);
     const bool has_start_time = start_time != kNoTimestamp();
 
     // Always prefer the video stream for seeking.  If none exists, we'll swap
     // the fallback stream with the preferred stream below.
@@ skipping 160 matching lines @@
   SetTimeProperty(metadata_event.get(), "max_duration", max_duration);
   SetTimeProperty(metadata_event.get(), "start_time", start_time_);
   metadata_event->params.SetInteger("bitrate", bitrate_);
   media_log_->AddEvent(std::move(metadata_event));
 
   media_tracks_updated_cb_.Run(std::move(media_tracks));
 
   status_cb.Run(PIPELINE_OK);
 }
 
+const DemuxerStream* FFmpegDemuxer::GetDemuxerStreamByTrackId(
+    MediaTrack::TrackId track_id) const {
+  auto it = track_id_to_demux_stream_map_.find(track_id);
+  DCHECK(it != track_id_to_demux_stream_map_.end());
+  return it->second;
+}
+
 void FFmpegDemuxer::OnSeekFrameDone(const PipelineStatusCB& cb, int result) {
   DCHECK(task_runner_->BelongsToCurrentThread());
   CHECK(pending_seek_);
   pending_seek_ = false;
 
   if (!blocking_thread_.IsRunning()) {
     MEDIA_LOG(ERROR, media_log_) << GetDisplayName() << ": bad state";
     cb.Run(PIPELINE_ERROR_ABORT);
     return;
   }
@@ skipping 159 matching lines @@
 
 void FFmpegDemuxer::SetLiveness(DemuxerStream::Liveness liveness) {
   DCHECK(task_runner_->BelongsToCurrentThread());
   for (const auto& stream : streams_) {  // |stream| is a ref to a pointer.
     if (stream)
       stream->SetLiveness(liveness);
   }
 }
 
 }  // namespace media