audio_buffer.h revision eb525c5499e34cc9c4b825d6d9e75bb07cc06ace 
1// Copyright 2013 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_BUFFER_H_
6#define MEDIA_BASE_AUDIO_BUFFER_H_
7
8#include <vector>
9
10#include "base/memory/aligned_memory.h"
11#include "base/memory/ref_counted.h"
12#include "base/memory/scoped_ptr.h"
13#include "base/time/time.h"
14#include "media/base/media_export.h"
15#include "media/base/sample_format.h"
16
17namespace media {
18class AudioBus;
19
20// An audio buffer that takes a copy of the data passed to it, holds it, and
21// copies it into an AudioBus when needed. Also supports an end of stream
22// marker.
23class MEDIA_EXPORT AudioBuffer
24    : public base::RefCountedThreadSafe<AudioBuffer> {
25 public:
26  // Create an AudioBuffer whose channel data is copied from |data|. For
27  // interleaved data, only the first buffer is used. For planar data, the
28  // number of buffers must be equal to |channel_count|. |frame_count| is the
29  // number of frames in each buffer. |data| must not be null and |frame_count|
30  // must be >= 0.
31  //
32  // TODO(jrummell): Compute duration rather than pass it in.
33  static scoped_refptr<AudioBuffer> CopyFrom(SampleFormat sample_format,
34                                             int channel_count,
35                                             int frame_count,
36                                             const uint8* const* data,
37                                             const base::TimeDelta timestamp,
38                                             const base::TimeDelta duration);
39
40  // Create a AudioBuffer indicating we've reached end of stream.
41  // Calling any method other than end_of_stream() on the resulting buffer
42  // is disallowed.
43  static scoped_refptr<AudioBuffer> CreateEOSBuffer();
44
45  // Copy frames into |dest|. |frames_to_copy| is the number of frames to copy.
46  // |source_frame_offset| specified how many frames in the buffer to skip
47  // first. |dest_frame_offset| is the frame offset in |dest|. The frames are
48  // converted from their source format into planar float32 data (which is all
49  // that AudioBus handles).
50  void ReadFrames(int frames_to_copy,
51                  int source_frame_offset,
52                  int dest_frame_offset,
53                  AudioBus* dest);
54
55  // Return the number of frames held.
56  int frame_count() const { return frame_count_; }
57
58  // Access to constructor parameters.
59  base::TimeDelta timestamp() const { return timestamp_; }
60  base::TimeDelta duration() const { return duration_; }
61
62  // If there's no data in this buffer, it represents end of stream.
63  bool end_of_stream() const { return data_ == NULL; }
64
65 private:
66  friend class base::RefCountedThreadSafe<AudioBuffer>;
67
68  // Allocates aligned contiguous buffer to hold all channel data (1 block for
69  // interleaved data, |channel_count| blocks for planar data), copies
70  // [data,data+data_size) to the allocated buffer(s). If |data| is null an end
71  // of stream buffer is created.
72  AudioBuffer(SampleFormat sample_format,
73              int channel_count,
74              int frame_count,
75              const uint8* const* data,
76              const base::TimeDelta timestamp,
77              const base::TimeDelta duration);
78
79  virtual ~AudioBuffer();
80
81  SampleFormat sample_format_;
82  int channel_count_;
83  int frame_count_;
84  base::TimeDelta timestamp_;
85  base::TimeDelta duration_;
86
87  // Contiguous block of channel data.
88  scoped_ptr_malloc<uint8, base::ScopedPtrAlignedFree> data_;
89
90  // For planar data, points to each channels data.
91  std::vector<uint8*> channel_data_;
92
93  DISALLOW_IMPLICIT_CONSTRUCTORS(AudioBuffer);
94};
95
96}  // namespace media
97
98#endif  // MEDIA_BASE_AUDIO_BUFFER_H_
99