media/filters/ffmpeg_audio_decoder.h

   1 // Copyright (c) 2011 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/message_loop.h"
  11 #include "media/base/filters.h"
  12
  13 struct AVCodecContext;
  14
  15 namespace media {
  16
  17 class DataBuffer;
  18
  19 class MEDIA_EXPORT FFmpegAudioDecoder : public AudioDecoder {
  20  public:
  21   explicit FFmpegAudioDecoder(MessageLoop* message_loop);
  22   virtual ~FFmpegAudioDecoder();
  23
  24   // Filter implementation.
  25   virtual void Flush(const base::Closure& callback) OVERRIDE;
  26
  27   // AudioDecoder implementation.
  28   virtual void Initialize(DemuxerStream* stream, const base::Closure& callback,
  29                           const StatisticsCallback& stats_callback) OVERRIDE;
  30   virtual void ProduceAudioSamples(scoped_refptr<Buffer> output) OVERRIDE;
  31   virtual int bits_per_channel() OVERRIDE;
  32   virtual ChannelLayout channel_layout() OVERRIDE;
  33   virtual int samples_per_second() OVERRIDE;
  34
  35  private:
  36   // Methods running on decoder thread.
  37   void DoInitialize(const scoped_refptr<DemuxerStream>& stream,
  38                     const base::Closure& callback,
  39                     const StatisticsCallback& stats_callback);
  40   void DoFlush(const base::Closure& callback);
  41   void DoProduceAudioSamples(const scoped_refptr<Buffer>& output);
  42   void DoDecodeBuffer(const scoped_refptr<Buffer>& input);
  43
  44   // Reads from the demuxer stream with corresponding callback method.
  45   void ReadFromDemuxerStream();
  46   void DecodeBuffer(const scoped_refptr<Buffer>& buffer);
  47
  48   // Updates the output buffer's duration and timestamp based on the input
  49   // buffer. Will fall back to an estimated timestamp if the input lacks a
  50   // valid timestamp.
  51   void UpdateDurationAndTimestamp(const Buffer* input, DataBuffer* output);
  52
  53   // Calculates duration based on size of decoded audio bytes.
  54   base::TimeDelta CalculateDuration(int size);
  55
  56   MessageLoop* message_loop_;
  57
  58   scoped_refptr<DemuxerStream> demuxer_stream_;
  59   StatisticsCallback stats_callback_;
  60   AVCodecContext* codec_context_;
  61
  62   // Decoded audio format.
  63   int bits_per_channel_;
  64   ChannelLayout channel_layout_;
  65   int samples_per_second_;
  66
  67   base::TimeDelta estimated_next_timestamp_;
  68
  69   // Holds decoded audio. As required by FFmpeg, input/output buffers should
  70   // be allocated with suitable padding and alignment. av_malloc() provides
  71   // us that guarantee.
  72   const int decoded_audio_size_;
  73   uint8* decoded_audio_;  // Allocated via av_malloc().
  74
  75   // Holds downstream-provided buffers.
  76   std::list<scoped_refptr<Buffer> > output_buffers_;
  77
  78   // Tracks reads issued for compressed data.
  79   int pending_reads_;
  80
  81   DISALLOW_IMPLICIT_CONSTRUCTORS(FFmpegAudioDecoder);
  82 };
  83
  84 }  // namespace media
  85
  86 #endif  // MEDIA_FILTERS_FFMPEG_AUDIO_DECODER_H_