media/filters/ffmpeg_audio_decoder.h

// Copyright (c) 2009 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 "media/base/factory.h"
#include "media/filters/decoder_base.h"

struct AVCodecContext;

namespace media {

// Forward declaration for scoped_ptr_malloc.
class ScopedPtrAVFree;

class FFmpegAudioDecoder : public DecoderBase<AudioDecoder, Buffer> {
 public:
  static FilterFactory* CreateFactory() {
    return new FilterFactoryImpl0<FFmpegAudioDecoder>();
  }

  static bool IsMediaFormatSupported(const MediaFormat& media_format);

  virtual bool OnInitialize(DemuxerStream* demuxer_stream);

  virtual void OnStop();

  virtual void OnDecode(Buffer* input);

 private:
  friend class FilterFactoryImpl0<FFmpegAudioDecoder>;
  FFmpegAudioDecoder();
  virtual ~FFmpegAudioDecoder();

  // Calculates the duration of an audio buffer based on the sample rate,
  // channels and bits per sample given the size in bytes.
  base::TimeDelta CalculateDuration(size_t size);

  // A FFmpeg defined structure that holds decoder information, this variable
  // is initialized in OnInitialize().
  AVCodecContext* codec_context_;

  // Data buffer to carry decoded raw PCM samples. This buffer is created by
  // av_malloc() and is used throughout the lifetime of this class.
  scoped_ptr_malloc<uint8, ScopedPtrAVFree> output_buffer_;

  static const size_t kOutputBufferSize;

  DISALLOW_COPY_AND_ASSIGN(FFmpegAudioDecoder);
};

}  // namespace media

#endif  // MEDIA_FILTERS_FFMPEG_AUDIO_DECODER_H_