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_BUS_H_
6#define MEDIA_BASE_AUDIO_BUS_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 "media/base/media_export.h"
14
15namespace media {
16class AudioParameters;
17
18// Scoped container for "busing" audio channel data around.  Each channel is
19// stored in planar format and guaranteed to be aligned by kChannelAlignment.
20// AudioBus objects can be created normally or via wrapping.  Normally, AudioBus
21// will dice up a contiguous memory block for channel data.  When wrapped,
22// AudioBus instead routes requests for channel data to the wrapped object.
23class MEDIA_EXPORT AudioBus {
24 public:
25  // Guaranteed alignment of each channel's data; use 16-byte alignment for easy
26  // SSE optimizations.
27  enum { kChannelAlignment = 16 };
28
29  // Creates a new AudioBus and allocates |channels| of length |frames|.  Uses
30  // channels() and frames_per_buffer() from AudioParameters if given.
31  static scoped_ptr<AudioBus> Create(int channels, int frames);
32  static scoped_ptr<AudioBus> Create(const AudioParameters& params);
33
34  // Creates a new AudioBus with the given number of channels, but zero length.
35  // It's expected to be used with SetChannelData() and set_frames() to
36  // wrap externally allocated memory.
37  static scoped_ptr<AudioBus> CreateWrapper(int channels);
38
39  // Creates a new AudioBus from an existing channel vector.  Does not transfer
40  // ownership of |channel_data| to AudioBus; i.e., |channel_data| must outlive
41  // the returned AudioBus.  Each channel must be aligned by kChannelAlignment.
42  static scoped_ptr<AudioBus> WrapVector(
43      int frames, const std::vector<float*>& channel_data);
44
45  // Creates a new AudioBus by wrapping an existing block of memory.  Block must
46  // be at least CalculateMemorySize() bytes in size.  |data| must outlive the
47  // returned AudioBus.  |data| must be aligned by kChannelAlignment.
48  static scoped_ptr<AudioBus> WrapMemory(int channels, int frames, void* data);
49  static scoped_ptr<AudioBus> WrapMemory(const AudioParameters& params,
50                                         void* data);
51  static int CalculateMemorySize(const AudioParameters& params);
52
53  // Calculates the required size for an AudioBus given the number of channels
54  // and frames.
55  static int CalculateMemorySize(int channels, int frames);
56
57  // Helper methods for converting an AudioBus from and to interleaved integer
58  // data.  Expects interleaving to be [ch0, ch1, ..., chN, ch0, ch1, ...] with
59  // |bytes_per_sample| per value.  Values are scaled and bias corrected during
60  // conversion.  ToInterleaved() will also clip values to format range.
61  // Handles uint8, int16, and int32 currently.  FromInterleaved() will zero out
62  // any unfilled frames when |frames| is less than frames().
63  void FromInterleaved(const void* source, int frames, int bytes_per_sample);
64  void ToInterleaved(int frames, int bytes_per_sample, void* dest) const;
65  void ToInterleavedPartial(int start_frame, int frames, int bytes_per_sample,
66                            void* dest) const;
67
68  // Similar to FromInterleaved() above, but meant for streaming sources.  Does
69  // not zero out remaining frames, the caller is responsible for doing so using
70  // ZeroFramesPartial().  Frames are deinterleaved from the start of |source|
71  // to channel(x)[start_frame].
72  void FromInterleavedPartial(const void* source, int start_frame, int frames,
73                              int bytes_per_sample);
74
75  // Helper method for copying channel data from one AudioBus to another.  Both
76  // AudioBus object must have the same frames() and channels().
77  void CopyTo(AudioBus* dest) const;
78
79  // Helper method to copy frames from one AudioBus to another. Both AudioBus
80  // objects must have the same number of channels(). |source_start_frame| is
81  // the starting offset. |dest_start_frame| is the starting offset in |dest|.
82  // |frame_count| is the number of frames to copy.
83  void CopyPartialFramesTo(int source_start_frame,
84                           int frame_count,
85                           int dest_start_frame,
86                           AudioBus* dest) const;
87
88  // Returns a raw pointer to the requested channel.  Pointer is guaranteed to
89  // have a 16-byte alignment.  Warning: Do not rely on having sane (i.e. not
90  // inf, nan, or between [-1.0, 1.0]) values in the channel data.
91  float* channel(int channel) { return channel_data_[channel]; }
92  const float* channel(int channel) const { return channel_data_[channel]; }
93  void SetChannelData(int channel, float* data);
94
95  int channels() const { return static_cast<int>(channel_data_.size()); }
96  int frames() const { return frames_; }
97  void set_frames(int frames);
98
99  // Helper method for zeroing out all channels of audio data.
100  void Zero();
101  void ZeroFrames(int frames);
102  void ZeroFramesPartial(int start_frame, int frames);
103
104  // Scale internal channel values by |volume| >= 0.  If an invalid value
105  // is provided, no adjustment is done.
106  void Scale(float volume);
107
108  // Swaps channels identified by |a| and |b|.  The caller needs to make sure
109  // the channels are valid.
110  void SwapChannels(int a, int b);
111
112  virtual ~AudioBus();
113
114 protected:
115  AudioBus(int channels, int frames);
116  AudioBus(int channels, int frames, float* data);
117  AudioBus(int frames, const std::vector<float*>& channel_data);
118  explicit AudioBus(int channels);
119
120 private:
121  // Helper method for building |channel_data_| from a block of memory.  |data|
122  // must be at least BlockSize() bytes in size.
123  void BuildChannelData(int channels, int aligned_frame, float* data);
124
125  // Contiguous block of channel memory.
126  scoped_ptr<float, base::AlignedFreeDeleter> data_;
127
128  std::vector<float*> channel_data_;
129  int frames_;
130
131  // Protect SetChannelData() and set_frames() for use by CreateWrapper().
132  bool can_set_channel_data_;
133
134  DISALLOW_COPY_AND_ASSIGN(AudioBus);
135};
136
137// RefCounted version of AudioBus. This is not meant for general use. Only use
138// this when your lifetime requirements make it impossible to use an
139// AudioBus scoped_ptr.
140class MEDIA_EXPORT AudioBusRefCounted
141    : public media::AudioBus,
142      public base::RefCountedThreadSafe<AudioBusRefCounted> {
143 public:
144  static scoped_refptr<AudioBusRefCounted> Create(int channels, int frames);
145
146 private:
147  friend class base::RefCountedThreadSafe<AudioBusRefCounted>;
148
149  AudioBusRefCounted(int channels, int frames);
150  virtual ~AudioBusRefCounted();
151
152  DISALLOW_COPY_AND_ASSIGN(AudioBusRefCounted);
153};
154
155}  // namespace media
156
157#endif  // MEDIA_BASE_AUDIO_BUS_H_
158