1/*
2 * Copyright (C) 2011, 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#include "config.h"
26
27#if ENABLE(WEB_AUDIO)
28
29#include "WaveShaperDSPKernel.h"
30
31#include "WaveShaperProcessor.h"
32#include <algorithm>
33#include <wtf/MainThread.h>
34#include <wtf/Threading.h>
35
36const unsigned RenderingQuantum = 128;
37
38namespace WebCore {
39
40WaveShaperDSPKernel::WaveShaperDSPKernel(WaveShaperProcessor* processor)
41 : AudioDSPKernel(processor)
42{
43 if (processor->oversample() != WaveShaperProcessor::OverSampleNone)
44 lazyInitializeOversampling();
45}
46
47void WaveShaperDSPKernel::lazyInitializeOversampling()
48{
49 ASSERT(isMainThread());
50
51 if (!m_tempBuffer) {
52 m_tempBuffer = std::make_unique<AudioFloatArray>(RenderingQuantum * 2);
53 m_tempBuffer2 = std::make_unique<AudioFloatArray>(RenderingQuantum * 4);
54 m_upSampler = std::make_unique<UpSampler>(RenderingQuantum);
55 m_downSampler = std::make_unique<DownSampler>(RenderingQuantum * 2);
56 m_upSampler2 = std::make_unique<UpSampler>(RenderingQuantum * 2);
57 m_downSampler2 = std::make_unique<DownSampler>(RenderingQuantum * 4);
58 }
59}
60
61void WaveShaperDSPKernel::process(const float* source, float* destination, size_t framesToProcess)
62{
63 switch (waveShaperProcessor()->oversample()) {
64 case WaveShaperProcessor::OverSampleNone:
65 processCurve(source, destination, framesToProcess);
66 break;
67 case WaveShaperProcessor::OverSample2x:
68 processCurve2x(source, destination, framesToProcess);
69 break;
70 case WaveShaperProcessor::OverSample4x:
71 processCurve4x(source, destination, framesToProcess);
72 break;
73
74 default:
75 ASSERT_NOT_REACHED();
76 }
77}
78
79void WaveShaperDSPKernel::processCurve(const float* source, float* destination, size_t framesToProcess)
80{
81 ASSERT(source && destination && waveShaperProcessor());
82
83 Float32Array* curve = waveShaperProcessor()->curve();
84 if (!curve) {
85 // Act as "straight wire" pass-through if no curve is set.
86 memcpy(destination, source, sizeof(float) * framesToProcess);
87 return;
88 }
89
90 float* curveData = curve->data();
91 int curveLength = curve->length();
92
93 ASSERT(curveData);
94
95 if (!curveData || !curveLength) {
96 memcpy(destination, source, sizeof(float) * framesToProcess);
97 return;
98 }
99
100 // Apply waveshaping curve.
101 for (unsigned i = 0; i < framesToProcess; ++i) {
102 const float input = source[i];
103
104 // Calculate a virtual index based on input -1 -> +1 with 0 being at the center of the curve data.
105 // Then linearly interpolate between the two points in the curve.
106 double virtualIndex = 0.5 * (input + 1) * curveLength;
107 int index1 = static_cast<int>(virtualIndex);
108 int index2 = index1 + 1;
109 double interpolationFactor = virtualIndex - index1;
110
111 // Clip index to the input range of the curve.
112 // This takes care of input outside of nominal range -1 -> +1
113 index1 = std::max(index1, 0);
114 index1 = std::min(index1, curveLength - 1);
115 index2 = std::max(index2, 0);
116 index2 = std::min(index2, curveLength - 1);
117
118 double value1 = curveData[index1];
119 double value2 = curveData[index2];
120
121 double output = (1.0 - interpolationFactor) * value1 + interpolationFactor * value2;
122 destination[i] = output;
123 }
124}
125
126void WaveShaperDSPKernel::processCurve2x(const float* source, float* destination, size_t framesToProcess)
127{
128 bool isSafe = framesToProcess == RenderingQuantum;
129 ASSERT(isSafe);
130 if (!isSafe)
131 return;
132
133 float* tempP = m_tempBuffer->data();
134
135 m_upSampler->process(source, tempP, framesToProcess);
136
137 // Process at 2x up-sampled rate.
138 processCurve(tempP, tempP, framesToProcess * 2);
139
140 m_downSampler->process(tempP, destination, framesToProcess * 2);
141}
142
143void WaveShaperDSPKernel::processCurve4x(const float* source, float* destination, size_t framesToProcess)
144{
145 bool isSafe = framesToProcess == RenderingQuantum;
146 ASSERT(isSafe);
147 if (!isSafe)
148 return;
149
150 float* tempP = m_tempBuffer->data();
151 float* tempP2 = m_tempBuffer2->data();
152
153 m_upSampler->process(source, tempP, framesToProcess);
154 m_upSampler2->process(tempP, tempP2, framesToProcess * 2);
155
156 // Process at 4x up-sampled rate.
157 processCurve(tempP2, tempP2, framesToProcess * 4);
158
159 m_downSampler2->process(tempP2, tempP, framesToProcess * 4);
160 m_downSampler->process(tempP, destination, framesToProcess * 2);
161}
162
163void WaveShaperDSPKernel::reset()
164{
165 if (m_upSampler) {
166 m_upSampler->reset();
167 m_downSampler->reset();
168 m_upSampler2->reset();
169 m_downSampler2->reset();
170 }
171}
172
173double WaveShaperDSPKernel::latencyTime() const
174{
175 size_t latencyFrames = 0;
176 WaveShaperDSPKernel* kernel = const_cast<WaveShaperDSPKernel*>(this);
177
178 switch (kernel->waveShaperProcessor()->oversample()) {
179 case WaveShaperProcessor::OverSampleNone:
180 break;
181 case WaveShaperProcessor::OverSample2x:
182 latencyFrames += m_upSampler->latencyFrames();
183 latencyFrames += m_downSampler->latencyFrames();
184 break;
185 case WaveShaperProcessor::OverSample4x:
186 {
187 // Account for first stage upsampling.
188 latencyFrames += m_upSampler->latencyFrames();
189 latencyFrames += m_downSampler->latencyFrames();
190
191 // Account for second stage upsampling.
192 // and divide by 2 to get back down to the regular sample-rate.
193 size_t latencyFrames2 = (m_upSampler2->latencyFrames() + m_downSampler2->latencyFrames()) / 2;
194 latencyFrames += latencyFrames2;
195 break;
196 }
197 default:
198 ASSERT_NOT_REACHED();
199 }
200
201 return static_cast<double>(latencyFrames) / sampleRate();
202}
203
204} // namespace WebCore
205
206#endif // ENABLE(WEB_AUDIO)
207