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 15 namespace media { 16 class 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. 23 class 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. 140 class 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
