media/filters/ffmpeg_audio_decoder.h

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef MEDIA_FILTERS_FFMPEG_AUDIO_DECODER_H_
   6 #define MEDIA_FILTERS_FFMPEG_AUDIO_DECODER_H_
   7
   8 #include <list>
   9
  10 #include "base/callback.h"
  11 #include "base/memory/weak_ptr.h"
  12 #include "base/time/time.h"
  13 #include "media/base/audio_decoder.h"
  14 #include "media/base/demuxer_stream.h"
  15 #include "media/base/sample_format.h"
  16
  17 struct AVCodecContext;
  18 struct AVFrame;
  19
  20 namespace base {
  21 class MessageLoopProxy;
  22 }
  23
  24 namespace media {
  25
  26 class AudioTimestampHelper;
  27 class DecoderBuffer;
  28 struct QueuedAudioBuffer;
  29
  30 class MEDIA_EXPORT FFmpegAudioDecoder : public AudioDecoder {
  31  public:
  32   explicit FFmpegAudioDecoder(
  33       const scoped_refptr<base::MessageLoopProxy>& message_loop);
  34   virtual ~FFmpegAudioDecoder();
  35
  36   // AudioDecoder implementation.
  37   virtual void Initialize(DemuxerStream* stream,
  38                           const PipelineStatusCB& status_cb,
  39                           const StatisticsCB& statistics_cb) OVERRIDE;
  40   virtual void Read(const ReadCB& read_cb) OVERRIDE;
  41   virtual int bits_per_channel() OVERRIDE;
  42   virtual ChannelLayout channel_layout() OVERRIDE;
  43   virtual int samples_per_second() OVERRIDE;
  44   virtual void Reset(const base::Closure& closure) OVERRIDE;
  45
  46   // Callback called from within FFmpeg to allocate a buffer based on
  47   // the dimensions of |codec_context|. See AVCodecContext.get_buffer2
  48   // documentation inside FFmpeg.
  49   int GetAudioBuffer(AVCodecContext* codec, AVFrame* frame, int flags);
  50
  51  private:
  52   // Reads from the demuxer stream with corresponding callback method.
  53   void ReadFromDemuxerStream();
  54   void BufferReady(DemuxerStream::Status status,
  55                    const scoped_refptr<DecoderBuffer>& input);
  56
  57   bool ConfigureDecoder();
  58   void ReleaseFFmpegResources();
  59   void ResetTimestampState();
  60   void RunDecodeLoop(const scoped_refptr<DecoderBuffer>& input,
  61                      bool skip_eos_append);
  62
  63   scoped_refptr<base::MessageLoopProxy> message_loop_;
  64   base::WeakPtrFactory<FFmpegAudioDecoder> weak_factory_;
  65   base::WeakPtr<FFmpegAudioDecoder> weak_this_;
  66
  67   DemuxerStream* demuxer_stream_;
  68   StatisticsCB statistics_cb_;
  69   AVCodecContext* codec_context_;
  70
  71   // Decoded audio format.
  72   int bytes_per_channel_;
  73   ChannelLayout channel_layout_;
  74   int channels_;
  75   int samples_per_second_;
  76
  77   // AVSampleFormat initially requested; not Chrome's SampleFormat.
  78   int av_sample_format_;
  79   SampleFormat sample_format_;
  80
  81   // Used for computing output timestamps.
  82   scoped_ptr<AudioTimestampHelper> output_timestamp_helper_;
  83   base::TimeDelta last_input_timestamp_;
  84
  85   // Number of frames to drop before generating output buffers.
  86   int output_frames_to_drop_;
  87
  88   // Holds decoded audio.
  89   AVFrame* av_frame_;
  90
  91   ReadCB read_cb_;
  92
  93   // Since multiple frames may be decoded from the same packet we need to queue
  94   // them up and hand them out as we receive Read() calls.
  95   std::list<QueuedAudioBuffer> queued_audio_;
  96
  97   DISALLOW_IMPLICIT_CONSTRUCTORS(FFmpegAudioDecoder);
  98 };
  99
 100 }  // namespace media
 101
 102 #endif  // MEDIA_FILTERS_FFMPEG_AUDIO_DECODER_H_