Stop audio FFmpegDemuxerStreams if we get notified that audio rendering is disabled.

media/filters/ffmpeg_demuxer.cc

Index: media/filters/ffmpeg_demuxer.cc
diff --git a/media/filters/ffmpeg_demuxer.cc b/media/filters/ffmpeg_demuxer.cc
index c1a056cdbb8f2dc4cc86b43b183725e6ee859547..620b9ab75939d6e28949b7f45c5e02ed7d6b1c29 100644
--- a/media/filters/ffmpeg_demuxer.cc
+++ b/media/filters/ffmpeg_demuxer.cc
@@ -153,6 +153,10 @@ base::TimeDelta FFmpegDemuxerStream::duration() {
   return duration_;
 }
 
+int FFmpegDemuxerStream::stream_index() {
+  return stream_->index;
+}
+
 DemuxerStream::Type FFmpegDemuxerStream::type() {
   return type_;
 }
@@ -490,6 +494,7 @@ void FFmpegDemuxer::InitializeTask(DataSource* data_source,
       AVStream* stream = format_context_->streams[i];
       scoped_refptr<FFmpegDemuxerStream> demuxer_stream(
           new FFmpegDemuxerStream(this, stream));
+
       if (!streams_[demuxer_stream->type()]) {
         no_supported_streams = false;
         streams_[demuxer_stream->type()] = demuxer_stream;
@@ -502,9 +507,6 @@ void FFmpegDemuxer::InitializeTask(DataSource* data_source,
             start_time_ = first_dts;
         }
       }
-      packet_streams_.push_back(demuxer_stream);
-    } else {
-      packet_streams_.push_back(NULL);
     }
   }
   if (no_supported_streams) {
@@ -641,18 +643,10 @@ void FFmpegDemuxer::DemuxTask() {
   // TODO(scherkus): should we post this back to the pipeline thread?  I'm
   // worried about downstream filters (i.e., decoders) executing on this
   // thread.
-  DCHECK_GE(packet->stream_index, 0);
-  DCHECK_LT(packet->stream_index, static_cast<int>(packet_streams_.size()));
-  FFmpegDemuxerStream* demuxer_stream = NULL;
-  size_t i = packet->stream_index;
-  // Defend against ffmpeg giving us a bad stream index.
-  if (i < packet_streams_.size()) {
-    demuxer_stream = packet_streams_[i];
-  }
-  if (demuxer_stream) {
-    // Queue the packet with the appropriate stream.  The stream takes
-    // ownership of the AVPacket.
-    if (packet.get()) {
+  for (StreamVector::iterator iter = streams_.begin();

[acolwell GONE FROM CHROMIUM, 2011/12/13 16:45:44]

I don't feel good about this iteration happening on every packet. If you want to
only have one vector own the stream, how about just changing packet_streams_ to
an index -> Type vector? Then you could just do something like
streams_[packet_stream_[packet->stream_index]]. When streams are disable you can
just update packet_stream_[packet->stream_index] to UNKNOWN and make sure
streams_[UNKNOWN] is always NULL.

[scherkus (not reviewing), 2011/12/13 17:24:56]

This loop unrolls to checking streams_[AUDIO]->stream_index() and
streams_[VIDEO]->stream_index(). True we're doing one additional comparison but
I'm skeptical doing bounds checking on packet->stream_index + an indirect lookup
is any better -- but we're really splitting hairs here!

Is your concern that |streams_| could change to be large and we wouldn't notice
the performance hit? I could hand unroll the loop as described above -- it would
likely clear things up a bit and also prevent needless looping.

+       iter != streams_.end();
+       ++iter) {
+    if ((*iter) && (*iter)->stream_index() == packet->stream_index) {
       // If a packet is returned by FFmpeg's av_parser_parse2()
       // the packet will reference an inner memory of FFmpeg.
       // In this case, the packet's "destruct" member is NULL,
@@ -660,7 +654,11 @@ void FFmpegDemuxer::DemuxTask() {
       // other codecs.  It is safe to call this function even if the packet does
       // not refer to inner memory from FFmpeg.
       av_dup_packet(packet.get());
-      demuxer_stream->EnqueuePacket(packet.release());
+
+      // Queue the packet with the appropriate stream.  The stream takes
+      // ownership of the AVPacket.
+      (*iter)->EnqueuePacket(packet.release());
+      break;
     }
   }
 
@@ -688,17 +686,8 @@ void FFmpegDemuxer::StopTask(const base::Closure& callback) {
 void FFmpegDemuxer::DisableAudioStreamTask() {
   DCHECK_EQ(MessageLoop::current(), message_loop_);
 
-  StreamVector::iterator iter;
-  for (size_t i = 0; i < packet_streams_.size(); ++i) {
-    if (!packet_streams_[i])
-      continue;
-
-    // If the codec type is audio, remove the reference. DemuxTask() will
-    // look for such reference, and this will result in deleting the
-    // audio packets after they are demuxed.
-    if (packet_streams_[i]->type() == DemuxerStream::AUDIO) {
-      packet_streams_[i] = NULL;
-    }
+  if (streams_[DemuxerStream::AUDIO]) {
+    streams_[DemuxerStream::AUDIO]->Stop();
   }
 }