/* * Copyright (C) 2010, Google Inc. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS'' AND ANY * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE * DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS BE LIABLE FOR ANY * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ #ifndef AudioBufferSourceNode_h #define AudioBufferSourceNode_h #include "AudioBuffer.h" #include "AudioBus.h" #include "AudioGain.h" #include "AudioPannerNode.h" #include "AudioResampler.h" #include "AudioSourceNode.h" #include "AudioSourceProvider.h" #include <wtf/PassRefPtr.h> #include <wtf/RefPtr.h> #include <wtf/Threading.h> namespace WebCore { class AudioContext; // AudioBufferSourceNode is an AudioNode representing an audio source from an in-memory audio asset represented by an AudioBuffer. // It generally will be used for short sounds which require a high degree of scheduling flexibility (can playback in rhythmically perfect ways). class AudioBufferSourceNode : public AudioSourceNode, public AudioSourceProvider { public: static PassRefPtr<AudioBufferSourceNode> create(AudioContext*, double sampleRate); virtual ~AudioBufferSourceNode(); // AudioNode virtual void process(size_t framesToProcess); virtual void reset(); // AudioSourceProvider // When process() is called, the resampler calls provideInput (in the audio thread) to gets its input stream. virtual void provideInput(AudioBus*, size_t numberOfFrames); // setBuffer() is called on the main thread. This is the buffer we use for playback. void setBuffer(AudioBuffer*); AudioBuffer* buffer() { return m_buffer.get(); } // numberOfChannels() returns the number of output channels. This value equals the number of channels from the buffer. // If a new buffer is set with a different number of channels, then this value will dynamically change. unsigned numberOfChannels(); // Play-state // noteOn(), noteGrainOn(), and noteOff() must all be called from the main thread. void noteOn(double when); void noteGrainOn(double when, double grainOffset, double grainDuration); void noteOff(double when); bool looping() const { return m_isLooping; } void setLooping(bool looping) { m_isLooping = looping; } AudioGain* gain() { return m_gain.get(); } AudioParam* playbackRate() { return m_playbackRate.get(); } // If a panner node is set, then we can incorporate doppler shift into the playback pitch rate. void setPannerNode(PassRefPtr<AudioPannerNode> pannerNode) { m_pannerNode = pannerNode; } private: AudioBufferSourceNode(AudioContext*, double sampleRate); // m_buffer holds the sample data which this node outputs. RefPtr<AudioBuffer> m_buffer; // Used for the "gain" and "playbackRate" attributes. RefPtr<AudioGain> m_gain; RefPtr<AudioParam> m_playbackRate; // m_isPlaying is set to true when noteOn() or noteGrainOn() is called. bool m_isPlaying; // 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. // If true, it will wrap around to the start of the buffer each time it reaches the end. bool m_isLooping; // This node is considered finished when it reaches the end of the buffer's sample data after noteOn() has been called. // This will only be set to true if m_isLooping == false. bool m_hasFinished; // 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"). double m_startTime; // in seconds // m_schedulingFrameDelay is the sample-accurate scheduling offset. // It's used so that we start rendering audio samples at a very precise point in time. // It will only be a non-zero value the very first render quantum that we render from the buffer. int m_schedulingFrameDelay; // m_readIndex is a sample-frame index into our buffer representing the current playback position. unsigned m_readIndex; // Granular playback bool m_isGrain; double m_grainOffset; // in seconds double m_grainDuration; // in seconds int m_grainFrameCount; // keeps track of which frame in the grain we're currently rendering // totalPitchRate() returns the instantaneous pitch rate (non-time preserving). // It incorporates the base pitch rate, any sample-rate conversion factor from the buffer, and any doppler shift from an associated panner node. double totalPitchRate(); // m_resampler performs the pitch rate changes to the buffer playback. AudioResampler m_resampler; // m_lastGain provides continuity when we dynamically adjust the gain. double m_lastGain; // We optionally keep track of a panner node which has a doppler shift that is incorporated into the pitch rate. RefPtr<AudioPannerNode> m_pannerNode; // This synchronizes process() with setBuffer() which can cause dynamic channel count changes. mutable Mutex m_processLock; // Reads the next framesToProcess sample-frames from the AudioBuffer into destinationBus. // A grain envelope will be applied if m_isGrain is set to true. void readFromBuffer(AudioBus* destinationBus, size_t framesToProcess); // readFromBufferWithGrainEnvelope() is a low-level blitter which reads from the AudioBuffer and applies a grain envelope. void readFromBufferWithGrainEnvelope(float* sourceL, float* sourceR, float* destinationL, float* destinationR, size_t framesToProcess); }; } // namespace WebCore #endif // AudioBufferSourceNode_h