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
  14 struct OpusMSDecoder;
  15
  16 namespace base {
  17 class MessageLoopProxy;
  18 }
  19
  20 namespace media {
  21
  22 class AudioBuffer;
  23 class AudioTimestampHelper;
  24 class DecoderBuffer;
  25 struct QueuedAudioBuffer;
  26
  27 class MEDIA_EXPORT OpusAudioDecoder : public AudioDecoder {
  28  public:
  29   explicit OpusAudioDecoder(
  30       const scoped_refptr<base::MessageLoopProxy>& message_loop);
  31   virtual ~OpusAudioDecoder();
  32
  33   // AudioDecoder implementation.
  34   virtual void Initialize(DemuxerStream* stream,
  35                           const PipelineStatusCB& status_cb,
  36                           const StatisticsCB& statistics_cb) OVERRIDE;
  37   virtual void Read(const ReadCB& read_cb) OVERRIDE;
  38   virtual int bits_per_channel() OVERRIDE;
  39   virtual ChannelLayout channel_layout() OVERRIDE;
  40   virtual int samples_per_second() OVERRIDE;
  41   virtual void Reset(const base::Closure& closure) OVERRIDE;
  42
  43  private:
  44   // Reads from the demuxer stream with corresponding callback method.
  45   void ReadFromDemuxerStream();
  46   void BufferReady(DemuxerStream::Status status,
  47                    const scoped_refptr<DecoderBuffer>& input);
  48
  49
  50   bool ConfigureDecoder();
  51   void CloseDecoder();
  52   void ResetTimestampState();
  53   bool Decode(const scoped_refptr<DecoderBuffer>& input,
  54               scoped_refptr<AudioBuffer>* output_buffer);
  55
  56   scoped_refptr<base::MessageLoopProxy> message_loop_;
  57   base::WeakPtrFactory<OpusAudioDecoder> weak_factory_;
  58   base::WeakPtr<OpusAudioDecoder> weak_this_;
  59
  60   DemuxerStream* demuxer_stream_;
  61   StatisticsCB statistics_cb_;
  62   OpusMSDecoder* opus_decoder_;
  63
  64   // Decoded audio format.
  65   int bits_per_channel_;
  66   ChannelLayout channel_layout_;
  67   int samples_per_second_;
  68
  69   // Used for computing output timestamps.
  70   scoped_ptr<AudioTimestampHelper> output_timestamp_helper_;
  71   base::TimeDelta last_input_timestamp_;
  72
  73   ReadCB read_cb_;
  74
  75   // Number of frames to be discarded from the start of the packet. This value
  76   // is respected for all packets except for the first one in the stream. For
  77   // the first packet in the stream, |frame_delay_at_start_| is used. This is
  78   // usually set to the SeekPreRoll value from the container whenever a seek
  79   // happens.
  80   int frames_to_discard_;
  81
  82   // Number of frames to be discarded at the start of the stream. This value
  83   // is typically the CodecDelay value from the container.
  84   int frame_delay_at_start_;
  85
  86   // Timestamp to be subtracted from all the frames. This is typically computed
  87   // from the CodecDelay value in the container.
  88   base::TimeDelta timestamp_offset_;
  89
  90   // Buffer for output from libopus.
  91   scoped_ptr<int16[]> output_buffer_;
  92
  93   DISALLOW_IMPLICIT_CONSTRUCTORS(OpusAudioDecoder);
  94 };
  95
  96 }  // namespace media
  97
  98 #endif  // MEDIA_FILTERS_OPUS_AUDIO_DECODER_H_