Implement disabling and enabling media tracks

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 249 matching lines @@
       task_runner_(base::ThreadTaskRunnerHandle::Get()),
       stream_(stream),
       audio_config_(audio_config.release()),
       video_config_(video_config.release()),
       type_(UNKNOWN),
       liveness_(LIVENESS_UNKNOWN),
       end_of_stream_(false),
       last_packet_timestamp_(kNoTimestamp()),
       last_packet_duration_(kNoTimestamp()),
       video_rotation_(VIDEO_ROTATION_0),
+      is_enabled_(true),
       fixup_negative_timestamps_(false) {
   DCHECK(demuxer_);
 
   bool is_encrypted = false;
   int rotation = 0;
   AVDictionaryEntry* rotation_entry = NULL;
 
   // Determine our media format.
   switch (stream->codec->codec_type) {
     case AVMEDIA_TYPE_AUDIO:
@@ skipping 326 matching lines @@
   // Don't accept any additional reads if we've been told to stop.
   // The |demuxer_| may have been destroyed in the pipeline thread.
   //
   // TODO(scherkus): it would be cleaner to reply with an error message.
   if (!demuxer_) {
     base::ResetAndReturn(&read_cb_).Run(
         DemuxerStream::kOk, DecoderBuffer::CreateEOSBuffer());
     return;
   }
 
+  if (!is_enabled_) {
+    DVLOG(1) << "Read from disabled stream, returning EOS";
+    base::ResetAndReturn(&read_cb_).Run(kOk, DecoderBuffer::CreateEOSBuffer());
+    return;
+  }
+
   SatisfyPendingRead();
 }
 
 void FFmpegDemuxerStream::EnableBitstreamConverter() {
   DCHECK(task_runner_->BelongsToCurrentThread());
 
 #if defined(USE_PROPRIETARY_CODECS)
   InitBitstreamConverter();
 #else
   NOTREACHED() << "Proprietary codecs not enabled.";
@@ skipping 43 matching lines @@
   DCHECK(task_runner_->BelongsToCurrentThread());
   DCHECK_EQ(type_, VIDEO);
   DCHECK(video_config_.get());
   return *video_config_;
 }
 
 VideoRotation FFmpegDemuxerStream::video_rotation() {
   return video_rotation_;
 }
 
+bool FFmpegDemuxerStream::enabled() const {
+  DCHECK(task_runner_->BelongsToCurrentThread());
+  return is_enabled_;
+}
+
+void FFmpegDemuxerStream::set_enabled(bool enabled, base::TimeDelta timestamp) {

[chcunningham, 2016/06/02 23:49:43]

I feel like we need some logic here to drop frames after we enable until we
observe the first key frame. I get that we have one file position, so we cant
seek like we did in chunk demuxer.

+  DCHECK(task_runner_->BelongsToCurrentThread());
+  if (enabled == is_enabled_)
+    return;
+
+  is_enabled_ = enabled;
+  if (!is_enabled_ && !read_cb_.is_null()) {
+    DVLOG(1) << "Read from disabled stream, returning EOS";
+    base::ResetAndReturn(&read_cb_).Run(kOk, DecoderBuffer::CreateEOSBuffer());
+    return;
+  }
+}
+
 void FFmpegDemuxerStream::SetLiveness(Liveness liveness) {
   DCHECK(task_runner_->BelongsToCurrentThread());
   DCHECK_EQ(liveness_, LIVENESS_UNKNOWN);
   liveness_ = liveness;
 }
 
 base::TimeDelta FFmpegDemuxerStream::GetElapsedTime() const {
   return ConvertStreamTimestamp(stream_->time_base, stream_->cur_dts);
 }
 
@@ skipping 842 matching lines @@
     //
     // https://code.google.com/p/chromium/issues/detail?id=169133#c10
     if (!packet->data) {
       ScopedAVPacket new_packet(new AVPacket());
       av_new_packet(new_packet.get(), 0);
       av_packet_copy_props(new_packet.get(), packet.get());
       packet.swap(new_packet);
     }
 
     FFmpegDemuxerStream* demuxer_stream = streams_[packet->stream_index];
-    demuxer_stream->EnqueuePacket(std::move(packet));
+    if (demuxer_stream->enabled())
+      demuxer_stream->EnqueuePacket(std::move(packet));
   }
 
   // Keep reading until we've reached capacity.
   ReadFrameIfNeeded();
 }
 
 bool FFmpegDemuxer::StreamsHaveAvailableCapacity() {
   DCHECK(task_runner_->BelongsToCurrentThread());
   StreamVector::iterator iter;
   for (iter = streams_.begin(); iter != streams_.end(); ++iter) {
@@ skipping 54 matching lines @@
 }
 
 const DemuxerStream* FFmpegDemuxer::GetDemuxerStreamByTrackId(
     unsigned track_id) const {
   const auto& it = track_id_to_demux_stream_.find(track_id);
   CHECK(it != track_id_to_demux_stream_.end());
   return it->second;
 }
 
 }  // namespace media