audio_decoder.h revision c2e0dbddbe15c98d52c4786dac06cb8952a8ae6d 
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_BASE_AUDIO_DECODER_H_
6#define MEDIA_BASE_AUDIO_DECODER_H_
7
8#include "base/callback.h"
9#include "base/memory/ref_counted.h"
10#include "media/base/channel_layout.h"
11#include "media/base/pipeline_status.h"
12#include "media/base/media_export.h"
13
14namespace media {
15
16class DataBuffer;
17class DemuxerStream;
18
19class MEDIA_EXPORT AudioDecoder {
20 public:
21  // Status codes for read operations.
22  enum Status {
23    kOk,
24    kAborted,
25    kDecodeError,
26  };
27
28  AudioDecoder();
29  virtual ~AudioDecoder();
30
31  // Initialize an AudioDecoder with the given DemuxerStream, executing the
32  // callback upon completion.
33  // statistics_cb is used to update global pipeline statistics.
34  virtual void Initialize(DemuxerStream* stream,
35                          const PipelineStatusCB& status_cb,
36                          const StatisticsCB& statistics_cb) = 0;
37
38  // Request samples to be decoded and returned via the provided callback.
39  // Only one read may be in flight at any given time.
40  //
41  // Implementations guarantee that the callback will not be called from within
42  // this method.
43  //
44  // Non-NULL sample buffer pointers will contain decoded audio data or may
45  // indicate the end of the stream. A NULL buffer pointer indicates an aborted
46  // Read(). This can happen if the DemuxerStream gets flushed and doesn't have
47  // any more data to return.
48  typedef base::Callback<void(Status, const scoped_refptr<DataBuffer>&)> ReadCB;
49  virtual void Read(const ReadCB& read_cb) = 0;
50
51  // Reset decoder state, dropping any queued encoded data.
52  virtual void Reset(const base::Closure& closure) = 0;
53
54  // Returns various information about the decoded audio format.
55  virtual int bits_per_channel() = 0;
56  virtual ChannelLayout channel_layout() = 0;
57  virtual int samples_per_second() = 0;
58
59 private:
60  DISALLOW_COPY_AND_ASSIGN(AudioDecoder);
61};
62
63}  // namespace media
64
65#endif  // MEDIA_BASE_AUDIO_DECODER_H_
66