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/scoped_ptr.h" 12 #include "media/base/media_export.h" 13 14 namespace media { 15 class AudioParameters; 16 17 // Scoped container for "busing" audio channel data around. Each channel is 18 // stored in planar format and guaranteed to be aligned by kChannelAlignment. 19 // AudioBus objects can be created normally or via wrapping. Normally, AudioBus 20 // will dice up a contiguous memory block for channel data. When wrapped, 21 // AudioBus instead routes requests for channel data to the wrapped object. 22 class MEDIA_EXPORT AudioBus { 23 public: 24 // Guaranteed alignment of each channel's data; use 16-byte alignment for easy 25 // SSE optimizations. 26 enum { kChannelAlignment = 16 }; 27 28 // Creates a new AudioBus and allocates |channels| of length |frames|. Uses 29 // channels() and frames_per_buffer() from AudioParameters if given. 30 static scoped_ptr<AudioBus> Create(int channels, int frames); 31 static scoped_ptr<AudioBus> Create(const AudioParameters& params); 32 33 // Creates a new AudioBus with the given number of channels, but zero length. 34 // It's expected to be used with SetChannelData() and set_frames() to 35 // wrap externally allocated memory. 36 static scoped_ptr<AudioBus> CreateWrapper(int channels); 37 38 // Creates a new AudioBus from an existing channel vector. Does not transfer 39 // ownership of |channel_data| to AudioBus; i.e., |channel_data| must outlive 40 // the returned AudioBus. Each channel must be aligned by kChannelAlignment. 41 static scoped_ptr<AudioBus> WrapVector( 42 int frames, const std::vector<float*>& channel_data); 43 44 // Creates a new AudioBus by wrapping an existing block of memory. Block must 45 // be at least CalculateMemorySize() bytes in size. |data| must outlive the 46 // returned AudioBus. |data| must be aligned by kChannelAlignment. 47 static scoped_ptr<AudioBus> WrapMemory(int channels, int frames, void* data); 48 static scoped_ptr<AudioBus> WrapMemory(const AudioParameters& params, 49 void* data); 50 static int CalculateMemorySize(const AudioParameters& params); 51 52 // Calculates the required size for an AudioBus given the number of channels 53 // and frames. 54 static int CalculateMemorySize(int channels, int frames); 55 56 // Helper methods for converting an AudioBus from and to interleaved integer 57 // data. Expects interleaving to be [ch0, ch1, ..., chN, ch0, ch1, ...] with 58 // |bytes_per_sample| per value. Values are scaled and bias corrected during 59 // conversion. ToInterleaved() will also clip values to format range. 60 // Handles uint8, int16, and int32 currently. FromInterleaved() will zero out 61 // any unfilled frames when |frames| is less than frames(). 62 void FromInterleaved(const void* source, int frames, int bytes_per_sample); 63 void ToInterleaved(int frames, int bytes_per_sample, void* dest) const; 64 void ToInterleavedPartial(int start_frame, int frames, int bytes_per_sample, 65 void* dest) const; 66 67 // Similar to FromInterleaved() above, but meant for streaming sources. Does 68 // not zero out remaining frames, the caller is responsible for doing so using 69 // ZeroFramesPartial(). Frames are deinterleaved from the start of |source| 70 // to channel(x)[start_frame]. 71 void FromInterleavedPartial(const void* source, int start_frame, int frames, 72 int bytes_per_sample); 73 74 // Helper method for copying channel data from one AudioBus to another. Both 75 // AudioBus object must have the same frames() and channels(). 76 void CopyTo(AudioBus* dest) const; 77 78 // Helper method to copy frames from one AudioBus to another. Both AudioBus 79 // objects must have the same number of channels(). |source_start_frame| is 80 // the starting offset. |dest_start_frame| is the starting offset in |dest|. 81 // |frame_count| is the number of frames to copy. 82 void CopyPartialFramesTo(int source_start_frame, 83 int frame_count, 84 int dest_start_frame, 85 AudioBus* dest) const; 86 87 // Returns a raw pointer to the requested channel. Pointer is guaranteed to 88 // have a 16-byte alignment. Warning: Do not rely on having sane (i.e. not 89 // inf, nan, or between [-1.0, 1.0]) values in the channel data. 90 float* channel(int channel) { return channel_data_[channel]; } 91 const float* channel(int channel) const { return channel_data_[channel]; } 92 void SetChannelData(int channel, float* data); 93 94 int channels() const { return static_cast<int>(channel_data_.size()); } 95 int frames() const { return frames_; } 96 void set_frames(int frames); 97 98 // Helper method for zeroing out all channels of audio data. 99 void Zero(); 100 void ZeroFrames(int frames); 101 void ZeroFramesPartial(int start_frame, int frames); 102 103 // Scale internal channel values by |volume| >= 0. If an invalid value 104 // is provided, no adjustment is done. 105 void Scale(float volume); 106 107 private: 108 friend struct base::DefaultDeleter<AudioBus>; 109 ~AudioBus(); 110 111 AudioBus(int channels, int frames); 112 AudioBus(int channels, int frames, float* data); 113 AudioBus(int frames, const std::vector<float*>& channel_data); 114 explicit AudioBus(int channels); 115 116 // Helper method for building |channel_data_| from a block of memory. |data| 117 // must be at least BlockSize() bytes in size. 118 void BuildChannelData(int channels, int aligned_frame, float* data); 119 120 // Contiguous block of channel memory. 121 scoped_ptr_malloc<float, base::ScopedPtrAlignedFree> data_; 122 123 std::vector<float*> channel_data_; 124 int frames_; 125 126 // Protect SetChannelData() and set_frames() for use by CreateWrapper(). 127 bool can_set_channel_data_; 128 129 DISALLOW_COPY_AND_ASSIGN(AudioBus); 130 }; 131 132 } // namespace media 133 134 #endif // MEDIA_BASE_AUDIO_BUS_H_ 135
