1 /* 2 * Copyright (C) 2010 Google Inc. All rights reserved. 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. Neither the name of Apple Computer, Inc. ("Apple") nor the names of 14 * its contributors may be used to endorse or promote products derived 15 * from this software without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY 18 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 19 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 20 * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY 21 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES 22 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 23 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND 24 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27 */ 28 29 #ifndef AudioBus_h 30 #define AudioBus_h 31 32 #include "core/platform/audio/AudioChannel.h" 33 #include "wtf/Noncopyable.h" 34 #include "wtf/PassOwnPtr.h" 35 #include "wtf/ThreadSafeRefCounted.h" 36 #include "wtf/Vector.h" 37 38 namespace WebCore { 39 40 // An AudioBus represents a collection of one or more AudioChannels. 41 // The data layout is "planar" as opposed to "interleaved". 42 // An AudioBus with one channel is mono, an AudioBus with two channels is stereo, etc. 43 class AudioBus : public ThreadSafeRefCounted<AudioBus> { 44 WTF_MAKE_NONCOPYABLE(AudioBus); 45 public: 46 enum { 47 ChannelLeft = 0, 48 ChannelRight = 1, 49 ChannelCenter = 2, // center and mono are the same 50 ChannelMono = 2, 51 ChannelLFE = 3, 52 ChannelSurroundLeft = 4, 53 ChannelSurroundRight = 5, 54 }; 55 56 enum { 57 LayoutCanonical = 0 58 // Can define non-standard layouts here 59 }; 60 61 enum ChannelInterpretation { 62 Speakers, 63 Discrete, 64 }; 65 66 // allocate indicates whether or not to initially have the AudioChannels created with managed storage. 67 // Normal usage is to pass true here, in which case the AudioChannels will memory-manage their own storage. 68 // If allocate is false then setChannelMemory() has to be called later on for each channel before the AudioBus is useable... 69 static PassRefPtr<AudioBus> create(unsigned numberOfChannels, size_t length, bool allocate = true); 70 71 // Tells the given channel to use an externally allocated buffer. 72 void setChannelMemory(unsigned channelIndex, float* storage, size_t length); 73 74 // Channels 75 unsigned numberOfChannels() const { return m_channels.size(); } 76 77 AudioChannel* channel(unsigned channel) { return m_channels[channel].get(); } 78 const AudioChannel* channel(unsigned channel) const { return const_cast<AudioBus*>(this)->m_channels[channel].get(); } 79 AudioChannel* channelByType(unsigned type); 80 const AudioChannel* channelByType(unsigned type) const; 81 82 // Number of sample-frames 83 size_t length() const { return m_length; } 84 85 // resizeSmaller() can only be called with a new length <= the current length. 86 // The data stored in the bus will remain undisturbed. 87 void resizeSmaller(size_t newLength); 88 89 // Sample-rate : 0.0 if unknown or "don't care" 90 float sampleRate() const { return m_sampleRate; } 91 void setSampleRate(float sampleRate) { m_sampleRate = sampleRate; } 92 93 // Zeroes all channels. 94 void zero(); 95 96 // Clears the silent flag on all channels. 97 void clearSilentFlag(); 98 99 // Returns true if the silent bit is set on all channels. 100 bool isSilent() const; 101 102 // Returns true if the channel count and frame-size match. 103 bool topologyMatches(const AudioBus &sourceBus) const; 104 105 // Creates a new buffer from a range in the source buffer. 106 // 0 may be returned if the range does not fit in the sourceBuffer 107 static PassRefPtr<AudioBus> createBufferFromRange(const AudioBus* sourceBuffer, unsigned startFrame, unsigned endFrame); 108 109 110 // Creates a new AudioBus by sample-rate converting sourceBus to the newSampleRate. 111 // setSampleRate() must have been previously called on sourceBus. 112 // Note: sample-rate conversion is already handled in the file-reading code for the mac port, so we don't need this. 113 static PassRefPtr<AudioBus> createBySampleRateConverting(const AudioBus* sourceBus, bool mixToMono, double newSampleRate); 114 115 // Creates a new AudioBus by mixing all the channels down to mono. 116 // If sourceBus is already mono, then the returned AudioBus will simply be a copy. 117 static PassRefPtr<AudioBus> createByMixingToMono(const AudioBus* sourceBus); 118 119 // Scales all samples by the same amount. 120 void scale(float scale); 121 122 void reset() { m_isFirstTime = true; } // for de-zippering 123 124 // Copies the samples from the source bus to this one. 125 // This is just a simple per-channel copy if the number of channels match, otherwise an up-mix or down-mix is done. 126 void copyFrom(const AudioBus& sourceBus, ChannelInterpretation = Speakers); 127 128 // Sums the samples from the source bus to this one. 129 // This is just a simple per-channel summing if the number of channels match, otherwise an up-mix or down-mix is done. 130 void sumFrom(const AudioBus& sourceBus, ChannelInterpretation = Speakers); 131 132 // Copy each channel from sourceBus into our corresponding channel. 133 // We scale by targetGain (and our own internal gain m_busGain), performing "de-zippering" to smoothly change from *lastMixGain to (targetGain*m_busGain). 134 // The caller is responsible for setting up lastMixGain to point to storage which is unique for every "stream" which will be applied to this bus. 135 // This represents the dezippering memory. 136 void copyWithGainFrom(const AudioBus &sourceBus, float* lastMixGain, float targetGain); 137 138 // Copies the sourceBus by scaling with sample-accurate gain values. 139 void copyWithSampleAccurateGainValuesFrom(const AudioBus &sourceBus, float* gainValues, unsigned numberOfGainValues); 140 141 // Returns maximum absolute value across all channels (useful for normalization). 142 float maxAbsValue() const; 143 144 // Makes maximum absolute value == 1.0 (if possible). 145 void normalize(); 146 147 static PassRefPtr<AudioBus> loadPlatformResource(const char* name, float sampleRate); 148 149 protected: 150 AudioBus() { }; 151 152 AudioBus(unsigned numberOfChannels, size_t length, bool allocate); 153 154 void speakersCopyFrom(const AudioBus&); 155 void discreteCopyFrom(const AudioBus&); 156 void speakersSumFrom(const AudioBus&); 157 void discreteSumFrom(const AudioBus&); 158 void speakersSumFrom5_1_ToMono(const AudioBus&); 159 160 size_t m_length; 161 Vector<OwnPtr<AudioChannel> > m_channels; 162 int m_layout; 163 float m_busGain; 164 OwnPtr<AudioFloatArray> m_dezipperGainValues; 165 bool m_isFirstTime; 166 float m_sampleRate; // 0.0 if unknown or N/A 167 }; 168 169 } // WebCore 170 171 #endif // AudioBus_h 172
