1/*
2 * Copyright (C) 2010, Google Inc. All rights reserved.
3 * Copyright (C) 2016, Apple Inc. All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
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 *
14 * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS'' AND ANY
15 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
16 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
17 * DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS BE LIABLE FOR ANY
18 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
19 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
20 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
21 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
23 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#include "config.h"
27
28#if ENABLE(WEB_AUDIO)
29
30#include "ConvolverNode.h"
31
32#include "AudioBuffer.h"
33#include "AudioNodeInput.h"
34#include "AudioNodeOutput.h"
35#include "Reverb.h"
36#include <wtf/IsoMallocInlines.h>
37
38// Note about empirical tuning:
39// The maximum FFT size affects reverb performance and accuracy.
40// If the reverb is single-threaded and processes entirely in the real-time audio thread,
41// it's important not to make this too high. In this case 8192 is a good value.
42// But, the Reverb object is multi-threaded, so we want this as high as possible without losing too much accuracy.
43// Very large FFTs will have worse phase errors. Given these constraints 32768 is a good compromise.
44const size_t MaxFFTSize = 32768;
45
46namespace WebCore {
47
48WTF_MAKE_ISO_ALLOCATED_IMPL(ConvolverNode);
49
50ConvolverNode::ConvolverNode(AudioContext& context, float sampleRate)
51 : AudioNode(context, sampleRate)
52{
53 setNodeType(NodeTypeConvolver);
54
55 addInput(std::make_unique<AudioNodeInput>(this));
56 addOutput(std::make_unique<AudioNodeOutput>(this, 2));
57
58 // Node-specific default mixing rules.
59 m_channelCount = 2;
60 m_channelCountMode = ClampedMax;
61 m_channelInterpretation = AudioBus::Speakers;
62
63 initialize();
64}
65
66ConvolverNode::~ConvolverNode()
67{
68 uninitialize();
69}
70
71void ConvolverNode::process(size_t framesToProcess)
72{
73 AudioBus* outputBus = output(0)->bus();
74 ASSERT(outputBus);
75
76 // Synchronize with possible dynamic changes to the impulse response.
77 std::unique_lock<Lock> lock(m_processMutex, std::try_to_lock);
78 if (!lock.owns_lock()) {
79 // Too bad - the try_lock() failed. We must be in the middle of setting a new impulse response.
80 outputBus->zero();
81 return;
82 }
83
84 if (!isInitialized() || !m_reverb.get())
85 outputBus->zero();
86 else {
87 // Process using the convolution engine.
88 // Note that we can handle the case where nothing is connected to the input, in which case we'll just feed silence into the convolver.
89 // FIXME: If we wanted to get fancy we could try to factor in the 'tail time' and stop processing once the tail dies down if
90 // we keep getting fed silence.
91 m_reverb->process(input(0)->bus(), outputBus, framesToProcess);
92 }
93}
94
95void ConvolverNode::reset()
96{
97 std::lock_guard<Lock> lock(m_processMutex);
98 if (m_reverb)
99 m_reverb->reset();
100}
101
102void ConvolverNode::initialize()
103{
104 if (isInitialized())
105 return;
106
107 AudioNode::initialize();
108}
109
110void ConvolverNode::uninitialize()
111{
112 if (!isInitialized())
113 return;
114
115 m_reverb = nullptr;
116 AudioNode::uninitialize();
117}
118
119ExceptionOr<void> ConvolverNode::setBuffer(AudioBuffer* buffer)
120{
121 ASSERT(isMainThread());
122
123 if (!buffer)
124 return { };
125
126 if (buffer->sampleRate() != context().sampleRate())
127 return Exception { NotSupportedError };
128
129 unsigned numberOfChannels = buffer->numberOfChannels();
130 size_t bufferLength = buffer->length();
131
132 // The current implementation supports only 1-, 2-, or 4-channel impulse responses, with the
133 // 4-channel response being interpreted as true-stereo (see Reverb class).
134 bool isChannelCountGood = (numberOfChannels == 1 || numberOfChannels == 2 || numberOfChannels == 4) && bufferLength;
135
136 if (!isChannelCountGood)
137 return Exception { NotSupportedError };
138
139 // Wrap the AudioBuffer by an AudioBus. It's an efficient pointer set and not a memcpy().
140 // This memory is simply used in the Reverb constructor and no reference to it is kept for later use in that class.
141 auto bufferBus = AudioBus::create(numberOfChannels, bufferLength, false);
142 for (unsigned i = 0; i < numberOfChannels; ++i)
143 bufferBus->setChannelMemory(i, buffer->channelData(i)->data(), bufferLength);
144
145 bufferBus->setSampleRate(buffer->sampleRate());
146
147 // Create the reverb with the given impulse response.
148 bool useBackgroundThreads = !context().isOfflineContext();
149 auto reverb = std::make_unique<Reverb>(bufferBus.get(), AudioNode::ProcessingSizeInFrames, MaxFFTSize, 2, useBackgroundThreads, m_normalize);
150
151 {
152 // Synchronize with process().
153 std::lock_guard<Lock> lock(m_processMutex);
154 m_reverb = WTFMove(reverb);
155 m_buffer = buffer;
156 }
157
158 return { };
159}
160
161AudioBuffer* ConvolverNode::buffer()
162{
163 ASSERT(isMainThread());
164 return m_buffer.get();
165}
166
167double ConvolverNode::tailTime() const
168{
169 return m_reverb ? m_reverb->impulseResponseLength() / static_cast<double>(sampleRate()) : 0;
170}
171
172double ConvolverNode::latencyTime() const
173{
174 return m_reverb ? m_reverb->latencyFrames() / static_cast<double>(sampleRate()) : 0;
175}
176
177} // namespace WebCore
178
179#endif // ENABLE(WEB_AUDIO)
180