Introduce AudioBufferMemoryPool to avoid thrashing on audio buffers.

media/filters/ffmpeg_audio_decoder.h

 // 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.
 
 #ifndef MEDIA_FILTERS_FFMPEG_AUDIO_DECODER_H_
 #define MEDIA_FILTERS_FFMPEG_AUDIO_DECODER_H_
 
 #include <list>
 #include <memory>
 
 #include "base/callback.h"
 #include "base/macros.h"
 #include "base/time/time.h"
+#include "media/base/audio_buffer.h"
 #include "media/base/audio_decoder.h"
 #include "media/base/demuxer_stream.h"
 #include "media/base/media_log.h"
 #include "media/base/sample_format.h"
 #include "media/ffmpeg/ffmpeg_deleters.h"
 
 struct AVCodecContext;
 struct AVFrame;
 
 namespace base {
@@ skipping 15 matching lines @@
   // AudioDecoder implementation.
   std::string GetDisplayName() const override;
   void Initialize(const AudioDecoderConfig& config,
                   CdmContext* cdm_context,
                   const InitCB& init_cb,
                   const OutputCB& output_cb) override;
   void Decode(const scoped_refptr<DecoderBuffer>& buffer,
               const DecodeCB& decode_cb) override;
   void Reset(const base::Closure& closure) override;
 
+  // Callback called from within FFmpeg to allocate a buffer based on the
+  // properties of |codec_context| and |frame|. See AVCodecContext.get_buffer2
+  // documentation inside FFmpeg.
+  int GetAudioBuffer(struct AVCodecContext* s, AVFrame* frame, int flags);
+
  private:
   // There are four states the decoder can be in:
   //
   // - kUninitialized: The decoder is not initialized.
   // - kNormal: This is the normal state. The decoder is idle and ready to
   //            decode input buffers, or is decoding an input buffer.
   // - kDecodeFinished: EOS buffer received, codec flushed and decode finished.
   //                    No further Decode() call should be made.
   // - kError: Unexpected error happened.
   //
@@ skipping 45 matching lines @@
 
   AudioDecoderConfig config_;
 
   // AVSampleFormat initially requested; not Chrome's SampleFormat.
   int av_sample_format_;
 
   std::unique_ptr<AudioDiscardHelper> discard_helper_;
 
   scoped_refptr<MediaLog> media_log_;
 
+  scoped_refptr<AudioBufferMemoryPool> pool_;
+
   DISALLOW_IMPLICIT_CONSTRUCTORS(FFmpegAudioDecoder);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_FILTERS_FFMPEG_AUDIO_DECODER_H_