audio_decoder.h revision effb81e5f8246d0db0270817048dc992db66e9fb 
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/audio_decoder_config.h"
11#include "media/base/channel_layout.h"
12#include "media/base/decoder_buffer.h"
13#include "media/base/media_export.h"
14#include "media/base/pipeline_status.h"
15
16namespace media {
17
18class AudioBuffer;
19class DemuxerStream;
20
21class MEDIA_EXPORT AudioDecoder {
22 public:
23  // Status codes for decode operations.
24  // TODO(rileya): Now that both AudioDecoder and VideoDecoder Status enums
25  // match, break them into a decoder_status.h.
26  enum Status {
27    kOk,  // We're all good.
28    kAborted,  // We aborted as a result of Stop() or Reset().
29    kNotEnoughData,  // Not enough data to produce a video frame.
30    kDecodeError,  // A decoding error occurred.
31    kDecryptError  // Decrypting error happened.
32  };
33
34  AudioDecoder();
35  virtual ~AudioDecoder();
36
37  // Initializes an AudioDecoder with the given DemuxerStream, executing the
38  // callback upon completion.
39  // statistics_cb is used to update global pipeline statistics.
40  virtual void Initialize(const AudioDecoderConfig& config,
41                          const PipelineStatusCB& status_cb) = 0;
42
43  // Requests samples to be decoded and returned via the provided callback.
44  // Only one decode may be in flight at any given time.
45  //
46  // Implementations guarantee that the callback will not be called from within
47  // this method.
48  //
49  // Non-NULL sample buffer pointers will contain decoded audio data or may
50  // indicate the end of the stream. A NULL buffer pointer indicates an aborted
51  // Decode().
52  typedef base::Callback<void(Status, const scoped_refptr<AudioBuffer>&)>
53      DecodeCB;
54  virtual void Decode(const scoped_refptr<DecoderBuffer>& buffer,
55                      const DecodeCB& decode_cb) = 0;
56
57  // Some AudioDecoders will queue up multiple AudioBuffers from a single
58  // DecoderBuffer, if we have any such queued buffers this will return the next
59  // one. Otherwise we return a NULL AudioBuffer.
60  virtual scoped_refptr<AudioBuffer> GetDecodeOutput();
61
62  // Resets decoder state, dropping any queued encoded data.
63  virtual void Reset(const base::Closure& closure) = 0;
64
65  // Stops decoder, fires any pending callbacks and sets the decoder to an
66  // uninitialized state. An AudioDecoder cannot be re-initialized after it has
67  // been stopped.
68  // Note that if Initialize() has been called, Stop() must be called and
69  // complete before deleting the decoder.
70  virtual void Stop(const base::Closure& closure) = 0;
71
72 private:
73  DISALLOW_COPY_AND_ASSIGN(AudioDecoder);
74};
75
76}  // namespace media
77
78#endif  // MEDIA_BASE_AUDIO_DECODER_H_
79