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 "AudioParam.h"
31#include "AudioScheduledSourceNode.h"
32#include "ExceptionCode.h"
33#include "PannerNode.h"
34#include <memory>
35#include <mutex>
36#include <wtf/PassRefPtr.h>
37#include <wtf/RefPtr.h>
38
39namespace WebCore {
40
41class 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
46class AudioBufferSourceNode : public AudioScheduledSourceNode {
47public:
48    static PassRefPtr<AudioBufferSourceNode> create(AudioContext*, float sampleRate);
49
50    virtual ~AudioBufferSourceNode();
51
52    // AudioNode
53    virtual void process(size_t framesToProcess) override;
54    virtual void reset() override;
55
56    // setBuffer() is called on the main thread.  This is the buffer we use for playback.
57    // returns true on success.
58    bool setBuffer(AudioBuffer*);
59    AudioBuffer* buffer() { return m_buffer.get(); }
60
61    // numberOfChannels() returns the number of output channels.  This value equals the number of channels from the buffer.
62    // If a new buffer is set with a different number of channels, then this value will dynamically change.
63    unsigned numberOfChannels();
64
65    // Play-state
66    void startGrain(double when, double grainOffset, ExceptionCode&);
67    void startGrain(double when, double grainOffset, double grainDuration, ExceptionCode&);
68
69#if ENABLE(LEGACY_WEB_AUDIO)
70    void noteGrainOn(double when, double grainOffset, double grainDuration, ExceptionCode&);
71#endif
72
73    // Note: the attribute was originally exposed as .looping, but to be more consistent in naming with <audio>
74    // and with how it's described in the specification, the proper attribute name is .loop
75    // The old attribute is kept for backwards compatibility.
76    bool loop() const { return m_isLooping; }
77    void setLoop(bool looping) { m_isLooping = looping; }
78
79    // Loop times in seconds.
80    double loopStart() const { return m_loopStart; }
81    double loopEnd() const { return m_loopEnd; }
82    void setLoopStart(double loopStart) { m_loopStart = loopStart; }
83    void setLoopEnd(double loopEnd) { m_loopEnd = loopEnd; }
84
85    // Deprecated.
86    bool looping();
87    void setLooping(bool);
88
89    AudioParam* gain() { return m_gain.get(); }
90    AudioParam* playbackRate() { return m_playbackRate.get(); }
91
92    // If a panner node is set, then we can incorporate doppler shift into the playback pitch rate.
93    void setPannerNode(PannerNode*);
94    void clearPannerNode();
95
96    // If we are no longer playing, propogate silence ahead to downstream nodes.
97    virtual bool propagatesSilence() const override;
98
99    // AudioScheduledSourceNode
100    virtual void finish() override;
101
102private:
103    AudioBufferSourceNode(AudioContext*, float sampleRate);
104
105    virtual double tailTime() const override { return 0; }
106    virtual double latencyTime() const override { return 0; }
107
108    // Returns true on success.
109    bool renderFromBuffer(AudioBus*, unsigned destinationFrameOffset, size_t numberOfFrames);
110
111    // Render silence starting from "index" frame in AudioBus.
112    inline bool renderSilenceAndFinishIfNotLooping(AudioBus*, unsigned index, size_t framesToProcess);
113
114    // m_buffer holds the sample data which this node outputs.
115    RefPtr<AudioBuffer> m_buffer;
116
117    // Pointers for the buffer and destination.
118    std::unique_ptr<const float*[]> m_sourceChannels;
119    std::unique_ptr<float*[]> m_destinationChannels;
120
121    // Used for the "gain" and "playbackRate" attributes.
122    RefPtr<AudioParam> m_gain;
123    RefPtr<AudioParam> m_playbackRate;
124
125    // 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.
126    // If true, it will wrap around to the start of the buffer each time it reaches the end.
127    bool m_isLooping;
128
129    double m_loopStart;
130    double m_loopEnd;
131
132    // m_virtualReadIndex is a sample-frame index into our buffer representing the current playback position.
133    // Since it's floating-point, it has sub-sample accuracy.
134    double m_virtualReadIndex;
135
136    // Granular playback
137    bool m_isGrain;
138    double m_grainOffset; // in seconds
139    double m_grainDuration; // in seconds
140
141    // totalPitchRate() returns the instantaneous pitch rate (non-time preserving).
142    // It incorporates the base pitch rate, any sample-rate conversion factor from the buffer, and any doppler shift from an associated panner node.
143    double totalPitchRate();
144
145    // m_lastGain provides continuity when we dynamically adjust the gain.
146    float m_lastGain;
147
148    // We optionally keep track of a panner node which has a doppler shift that is incorporated into
149    // the pitch rate. We manually manage ref-counting because we want to use RefTypeConnection.
150    PannerNode* m_pannerNode;
151
152    // This synchronizes process() with setBuffer() which can cause dynamic channel count changes.
153    mutable std::mutex m_processMutex;
154};
155
156} // namespace WebCore
157
158#endif // AudioBufferSourceNode_h
159