media/filters/opus_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_OPUS_AUDIO_DECODER_H_
   6 #define MEDIA_FILTERS_OPUS_AUDIO_DECODER_H_
   7
   8 #include "base/callback.h"
   9 #include "base/memory/weak_ptr.h"
  10 #include "base/time/time.h"
  11 #include "media/base/audio_decoder.h"
  12 #include "media/base/demuxer_stream.h"
  13 #include "media/base/sample_format.h"
  14
  15 struct OpusMSDecoder;
  16
  17 namespace base {
  18 class SingleThreadTaskRunner;
  19 }
  20
  21 namespace media {
  22
  23 class AudioBuffer;
  24 class AudioTimestampHelper;
  25 class DecoderBuffer;
  26 struct QueuedAudioBuffer;
  27
  28 class MEDIA_EXPORT OpusAudioDecoder : public AudioDecoder {
  29  public:
  30   explicit OpusAudioDecoder(
  31       const scoped_refptr<base::SingleThreadTaskRunner>& task_runner);
  32   virtual ~OpusAudioDecoder();
  33
  34   // AudioDecoder implementation.
  35   virtual void Initialize(DemuxerStream* stream,
  36                           const PipelineStatusCB& status_cb,
  37                           const StatisticsCB& statistics_cb) OVERRIDE;
  38   virtual void Read(const ReadCB& read_cb) OVERRIDE;
  39   virtual int bits_per_channel() OVERRIDE;
  40   virtual ChannelLayout channel_layout() OVERRIDE;
  41   virtual int samples_per_second() OVERRIDE;
  42   virtual void Reset(const base::Closure& closure) OVERRIDE;
  43
  44  private:
  45   // Reads from the demuxer stream with corresponding callback method.
  46   void ReadFromDemuxerStream();
  47   void BufferReady(DemuxerStream::Status status,
  48                    const scoped_refptr<DecoderBuffer>& input);
  49
  50
  51   bool ConfigureDecoder();
  52   void CloseDecoder();
  53   void ResetTimestampState();
  54   bool Decode(const scoped_refptr<DecoderBuffer>& input,
  55               scoped_refptr<AudioBuffer>* output_buffer);
  56
  57   scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
  58   base::WeakPtrFactory<OpusAudioDecoder> weak_factory_;
  59   base::WeakPtr<OpusAudioDecoder> weak_this_;
  60
  61   DemuxerStream* demuxer_stream_;
  62   StatisticsCB statistics_cb_;
  63   OpusMSDecoder* opus_decoder_;
  64
  65   // Decoded audio format.
  66   ChannelLayout channel_layout_;
  67   int samples_per_second_;
  68   const SampleFormat sample_format_;
  69   const int bits_per_channel_;
  70
  71   // Used for computing output timestamps.
  72   scoped_ptr<AudioTimestampHelper> output_timestamp_helper_;
  73   base::TimeDelta last_input_timestamp_;
  74
  75   ReadCB read_cb_;
  76
  77   // Number of frames to be discarded from the start of the packet. This value
  78   // is respected for all packets except for the first one in the stream. For
  79   // the first packet in the stream, |frame_delay_at_start_| is used. This is
  80   // usually set to the SeekPreRoll value from the container whenever a seek
  81   // happens.
  82   int frames_to_discard_;
  83
  84   // Number of frames to be discarded at the start of the stream. This value
  85   // is typically the CodecDelay value from the container.  This value should
  86   // only be applied when input timestamp is |start_input_timestamp_|.
  87   int frame_delay_at_start_;
  88   base::TimeDelta start_input_timestamp_;
  89
  90   // Timestamp to be subtracted from all the frames. This is typically computed
  91   // from the CodecDelay value in the container.
  92   base::TimeDelta timestamp_offset_;
  93
  94   DISALLOW_IMPLICIT_CONSTRUCTORS(OpusAudioDecoder);
  95 };
  96
  97 }  // namespace media
  98
  99 #endif  // MEDIA_FILTERS_OPUS_AUDIO_DECODER_H_