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 * 1. Redistributions of source code must retain the above copyright 8 * notice, this list of conditions and the following disclaimer. 9 * 2. Redistributions in binary form must reproduce the above copyright 10 * notice, this list of conditions and the following disclaimer in the 11 * documentation and/or other materials provided with the distribution. 12 * 13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS'' AND ANY 14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 15 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 16 * DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS BE LIABLE FOR ANY 17 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES 18 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 19 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON 20 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 21 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS 22 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 23 */ 24 25 #ifndef AudioBufferSourceNode_h 26 #define AudioBufferSourceNode_h 27 28 #include "AudioBuffer.h" 29 #include "AudioBus.h" 30 #include "AudioGain.h" 31 #include "AudioPannerNode.h" 32 #include "AudioResampler.h" 33 #include "AudioSourceNode.h" 34 #include "AudioSourceProvider.h" 35 #include <wtf/PassRefPtr.h> 36 #include <wtf/RefPtr.h> 37 #include <wtf/Threading.h> 38 39 namespace WebCore { 40 41 class AudioContext; 42 43 // AudioBufferSourceNode is an AudioNode representing an audio source from an in-memory audio asset represented by an AudioBuffer. 44 // It generally will be used for short sounds which require a high degree of scheduling flexibility (can playback in rhythmically perfect ways). 45 46 class AudioBufferSourceNode : public AudioSourceNode, public AudioSourceProvider { 47 public: 48 static PassRefPtr<AudioBufferSourceNode> create(AudioContext*, double sampleRate); 49 50 virtual ~AudioBufferSourceNode(); 51 52 // AudioNode 53 virtual void process(size_t framesToProcess); 54 virtual void reset(); 55 56 // AudioSourceProvider 57 // When process() is called, the resampler calls provideInput (in the audio thread) to gets its input stream. 58 virtual void provideInput(AudioBus*, size_t numberOfFrames); 59 60 // setBuffer() is called on the main thread. This is the buffer we use for playback. 61 void setBuffer(AudioBuffer*); buffer()62 AudioBuffer* buffer() { return m_buffer.get(); } 63 64 // numberOfChannels() returns the number of output channels. This value equals the number of channels from the buffer. 65 // If a new buffer is set with a different number of channels, then this value will dynamically change. 66 unsigned numberOfChannels(); 67 68 // Play-state 69 // noteOn(), noteGrainOn(), and noteOff() must all be called from the main thread. 70 void noteOn(double when); 71 void noteGrainOn(double when, double grainOffset, double grainDuration); 72 void noteOff(double when); 73 looping()74 bool looping() const { return m_isLooping; } setLooping(bool looping)75 void setLooping(bool looping) { m_isLooping = looping; } 76 gain()77 AudioGain* gain() { return m_gain.get(); } playbackRate()78 AudioParam* playbackRate() { return m_playbackRate.get(); } 79 80 // If a panner node is set, then we can incorporate doppler shift into the playback pitch rate. setPannerNode(PassRefPtr<AudioPannerNode> pannerNode)81 void setPannerNode(PassRefPtr<AudioPannerNode> pannerNode) { m_pannerNode = pannerNode; } 82 83 private: 84 AudioBufferSourceNode(AudioContext*, double sampleRate); 85 86 // m_buffer holds the sample data which this node outputs. 87 RefPtr<AudioBuffer> m_buffer; 88 89 // Used for the "gain" and "playbackRate" attributes. 90 RefPtr<AudioGain> m_gain; 91 RefPtr<AudioParam> m_playbackRate; 92 93 // m_isPlaying is set to true when noteOn() or noteGrainOn() is called. 94 bool m_isPlaying; 95 96 // If m_isLooping is false, then this node will be done playing and become inactive after it reaches the end of the sample data in the buffer. 97 // If true, it will wrap around to the start of the buffer each time it reaches the end. 98 bool m_isLooping; 99 100 // This node is considered finished when it reaches the end of the buffer's sample data after noteOn() has been called. 101 // This will only be set to true if m_isLooping == false. 102 bool m_hasFinished; 103 104 // m_startTime is the time to start playing based on the context's timeline (0.0 or a time less than the context's current time means "now"). 105 double m_startTime; // in seconds 106 107 // m_schedulingFrameDelay is the sample-accurate scheduling offset. 108 // It's used so that we start rendering audio samples at a very precise point in time. 109 // It will only be a non-zero value the very first render quantum that we render from the buffer. 110 int m_schedulingFrameDelay; 111 112 // m_readIndex is a sample-frame index into our buffer representing the current playback position. 113 unsigned m_readIndex; 114 115 // Granular playback 116 bool m_isGrain; 117 double m_grainOffset; // in seconds 118 double m_grainDuration; // in seconds 119 int m_grainFrameCount; // keeps track of which frame in the grain we're currently rendering 120 121 // totalPitchRate() returns the instantaneous pitch rate (non-time preserving). 122 // It incorporates the base pitch rate, any sample-rate conversion factor from the buffer, and any doppler shift from an associated panner node. 123 double totalPitchRate(); 124 125 // m_resampler performs the pitch rate changes to the buffer playback. 126 AudioResampler m_resampler; 127 128 // m_lastGain provides continuity when we dynamically adjust the gain. 129 double m_lastGain; 130 131 // We optionally keep track of a panner node which has a doppler shift that is incorporated into the pitch rate. 132 RefPtr<AudioPannerNode> m_pannerNode; 133 134 // This synchronizes process() with setBuffer() which can cause dynamic channel count changes. 135 mutable Mutex m_processLock; 136 137 // Reads the next framesToProcess sample-frames from the AudioBuffer into destinationBus. 138 // A grain envelope will be applied if m_isGrain is set to true. 139 void readFromBuffer(AudioBus* destinationBus, size_t framesToProcess); 140 141 // readFromBufferWithGrainEnvelope() is a low-level blitter which reads from the AudioBuffer and applies a grain envelope. 142 void readFromBufferWithGrainEnvelope(float* sourceL, float* sourceR, float* destinationL, float* destinationR, size_t framesToProcess); 143 }; 144 145 } // namespace WebCore 146 147 #endif // AudioBufferSourceNode_h 148