Add Stop() to AudioDecoder.

media/filters/ffmpeg_audio_decoder.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_audio_decoder.h"
 
 #include "base/bind.h"
 #include "base/callback_helpers.h"
 #include "base/location.h"
 #include "base/single_thread_task_runner.h"
@@ skipping 137 matching lines @@
 void FFmpegAudioDecoder::Reset(const base::Closure& closure) {
   DCHECK(task_runner_->BelongsToCurrentThread());
   base::Closure reset_cb = BindToCurrentLoop(closure);
 
   avcodec_flush_buffers(codec_context_.get());
   ResetTimestampState();
   queued_audio_.clear();
   reset_cb.Run();
 }
 
-FFmpegAudioDecoder::~FFmpegAudioDecoder() {
-  // TODO(scherkus): should we require Stop() to be called? this might end up
-  // getting called on a random thread due to refcounting.
+void FFmpegAudioDecoder::Stop(const base::Closure& closure) {
+  DCHECK(task_runner_->BelongsToCurrentThread());
+  base::Closure stop_cb = BindToCurrentLoop(closure);
+
+  avcodec_flush_buffers(codec_context_.get());

[DaleCurtis, 2014/01/08 00:30:54]

What made you add this?  We don't make a similar call in the FFmpeg video
decoder for Stop, only during Reset.  I'm not sure it's wrong, I'm just curious.

[rileya (GONE FROM CHROMIUM), 2014/01/08 21:05:50]

I'm not sure actually I think I saw it done in Reset and figured it couldn't
hurt. In any case, I got rid of it.

+  ResetTimestampState();
+  queued_audio_.clear();
   ReleaseFFmpegResources();
+
+  stop_cb.Run();

[xhwang, 2014/01/08 01:33:37]

Here and in Reset(), what if we have |read_cb_| pending? Usually in that case we
should abort the read, then satisfy reset_cb or stop_cb, or defer the reset/stop
process until Demuxer read is back.

You can add a TODO and fix this in another CL.

[rileya (GONE FROM CHROMIUM), 2014/01/08 21:05:50]

I'd wondered about this, added a TODO.

 }
 
+FFmpegAudioDecoder::~FFmpegAudioDecoder() {}
+
 int FFmpegAudioDecoder::GetAudioBuffer(AVCodecContext* codec,
                                        AVFrame* frame,
                                        int flags) {
   // Since this routine is called by FFmpeg when a buffer is required for audio
   // data, use the values supplied by FFmpeg (ignoring the current settings).
   // RunDecodeLoop() gets to determine if the buffer is useable or not.
   AVSampleFormat format = static_cast<AVSampleFormat>(frame->format);
   SampleFormat sample_format = AVSampleFormatToSampleFormat(format);
   int channels = DetermineChannels(frame);
   if ((channels <= 0) || (channels >= limits::kMaxChannels)) {
@@ skipping 358 matching lines @@
     // Decoding finished successfully, update statistics.
     if (result > 0) {
       PipelineStatistics statistics;
       statistics.audio_bytes_decoded = result;
       statistics_cb_.Run(statistics);
     }
   } while (packet.size > 0);
 }
 
 }  // namespace media