Use ffmpeg packet.pos for restarting reading after reenabling video

media/filters/ffmpeg_demuxer.h

Index: media/filters/ffmpeg_demuxer.h
diff --git a/media/filters/ffmpeg_demuxer.h b/media/filters/ffmpeg_demuxer.h
index bd223ab9ccb8c5fb115e67bd409bd5d80d1bb65c..3b16693bd3d46041090aed2c1ba3b94177b29af5 100644
--- a/media/filters/ffmpeg_demuxer.h
+++ b/media/filters/ffmpeg_demuxer.h
@@ -200,6 +200,8 @@ class MEDIA_EXPORT FFmpegDemuxerStream : public DemuxerStream {
   std::string encryption_key_id_;
   bool fixup_negative_timestamps_;
 
+  base::TimeDelta stream_capacity_;
+
   DISALLOW_COPY_AND_ASSIGN(FFmpegDemuxerStream);
 };
 
@@ -271,6 +273,10 @@ class MEDIA_EXPORT FFmpegDemuxer : public Demuxer {
   // FFmpeg callbacks during seeking.
   void OnSeekFrameDone(int result);
 
+  // Called when FFmpeg completes the seek initiated in
+  // OnSelectedVideoTrackChanged in order to restart the |stream|.
+  void OnSeekDoneForRestartingStream(FFmpegDemuxerStream* stream, int result);
+
   // FFmpeg callbacks during reading + helper method to initiate reads.
   void ReadFrameIfNeeded();
   void OnReadFrameDone(ScopedAVPacket packet, int result);
@@ -299,6 +305,16 @@ class MEDIA_EXPORT FFmpegDemuxer : public Demuxer {
 
   void SetLiveness(DemuxerStream::Liveness liveness);
 
+  // Do an FFmpeg seek such that the read position is adjusted to be able to
+  // restart playback from the |time| position. If the |preferred_stream| is not
+  // null then it is used for seeking, otherwise the preferred stream is
+  // selected by FindPreferredStreamForSeeking function. When the seek is
+  // completed the |ffmpeg_seek_done_cb| will be called with FFmpeg result.
+  using FFmpegSeekDoneCB = base::Callback<void(int ffmpeg_result)>;
+  void SeekInternal(base::TimeDelta time,
+                    FFmpegDemuxerStream* preferred_stream,
+                    const FFmpegSeekDoneCB& ffmpeg_seek_done_cb);

[DaleCurtis, 2017/05/24 22:24:18]

pass by value nowadays.

[servolk, 2017/05/24 22:58:20]

Done.

+
   DemuxerHost* host_;
 
   scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
@@ -319,6 +335,7 @@ class MEDIA_EXPORT FFmpegDemuxer : public Demuxer {
   // Tracks if there's an outstanding av_seek_frame() operation. Used to discard
   // results of pre-seek av_read_frame() operations.
   PipelineStatusCB pending_seek_cb_;
+  base::TimeDelta pending_seek_position_;
 
   // |streams_| mirrors the AVStream array in AVFormatContext. It contains
   // FFmpegDemuxerStreams encapsluating AVStream objects at the same index.
@@ -357,6 +374,12 @@ class MEDIA_EXPORT FFmpegDemuxer : public Demuxer {
   // fallback option.
   FFmpegDemuxerStream* FindPreferredStreamForSeeking(base::TimeDelta seek_time);
 
+  // Restarts a previous pending seek if a video stream got re-enabled while a
+  // pending seek was in progress.
+  void RestartPendingSeek(base::TimeDelta time,
+                          const PipelineStatusCB& cb,

[DaleCurtis, 2017/05/24 22:24:18]

Ditto.

+                          PipelineStatus prev_seek_status);
+
   // The Time associated with timestamp 0. Set to a null
   // time if the file doesn't have an association to Time.
   base::Time timeline_offset_;
@@ -379,6 +402,9 @@ class MEDIA_EXPORT FFmpegDemuxer : public Demuxer {
 
   std::map<MediaTrack::Id, FFmpegDemuxerStream*> track_id_to_demux_stream_map_;
 
+  int64_t last_audio_packet_pos_;
+  FFmpegDemuxerStream* restarting_stream_;
+
   // NOTE: Weak pointers must be invalidated before all other member variables.
   base::WeakPtr<FFmpegDemuxer> weak_this_;
   base::WeakPtrFactory<FFmpegDemuxer> cancel_pending_seek_factory_;