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 #include "config.h"
26
27 #if ENABLE(WEB_AUDIO)
28
29 #include "BiquadProcessor.h"
30
31 #include "BiquadDSPKernel.h"
32
33 namespace WebCore {
34
BiquadProcessor(FilterType type,double sampleRate,size_t numberOfChannels,bool autoInitialize)35 BiquadProcessor::BiquadProcessor(FilterType type, double sampleRate, size_t numberOfChannels, bool autoInitialize)
36 : AudioDSPKernelProcessor(sampleRate, numberOfChannels)
37 , m_type(type)
38 , m_parameter1(0)
39 , m_parameter2(0)
40 , m_parameter3(0)
41 , m_filterCoefficientsDirty(true)
42 {
43 double nyquist = 0.5 * this->sampleRate();
44
45 switch (type) {
46 // Highpass and lowpass share the same parameters and only differ in filter type.
47 case LowPass2:
48 case HighPass2:
49 m_parameter1 = AudioParam::create("frequency", 350.0, 20.0, nyquist);
50 m_parameter2 = AudioParam::create("resonance", 0.0, -20.0, 20.0);
51 m_parameter3 = AudioParam::create("unused", 0.0, 0.0, 1.0);
52 break;
53
54 case Peaking:
55 m_parameter1 = AudioParam::create("frequency", 2500.0, 20.0, nyquist);
56 m_parameter2 = AudioParam::create("gain", 0.0, -20.0, 20.0);
57 m_parameter3 = AudioParam::create("Q", 0.5, 0.0, 1000.0);
58 break;
59 case Allpass:
60 m_parameter1 = AudioParam::create("frequency", 2500.0, 20.0, nyquist);
61 m_parameter2 = AudioParam::create("Q", 0.5, 0.0, 1000.0);
62 m_parameter3 = AudioParam::create("unused", 0.0, 0.0, 1.0);
63 break;
64 case LowShelf:
65 m_parameter1 = AudioParam::create("frequency", 80.0, 20.0, nyquist);
66 m_parameter2 = AudioParam::create("gain", 0.0, 0.0, 1.0);
67 m_parameter3 = AudioParam::create("unused", 0.0, 0.0, 1.0);
68 break;
69 case HighShelf:
70 m_parameter1 = AudioParam::create("frequency", 10000.0, 20.0, nyquist);
71 m_parameter2 = AudioParam::create("gain", 0.0, 0.0, 1.0);
72 m_parameter3 = AudioParam::create("unused", 0.0, 0.0, 1.0);
73 break;
74 }
75
76 if (autoInitialize)
77 initialize();
78 }
79
~BiquadProcessor()80 BiquadProcessor::~BiquadProcessor()
81 {
82 if (isInitialized())
83 uninitialize();
84 }
85
createKernel()86 PassOwnPtr<AudioDSPKernel> BiquadProcessor::createKernel()
87 {
88 return adoptPtr(new BiquadDSPKernel(this));
89 }
90
process(AudioBus * source,AudioBus * destination,size_t framesToProcess)91 void BiquadProcessor::process(AudioBus* source, AudioBus* destination, size_t framesToProcess)
92 {
93 if (!isInitialized()) {
94 destination->zero();
95 return;
96 }
97
98 // Deal with smoothing / de-zippering. Start out assuming filter parameters are not changing.
99 // The BiquadDSPKernel objects rely on this value to see if they need to re-compute their internal filter coefficients.
100 m_filterCoefficientsDirty = false;
101
102 if (m_hasJustReset) {
103 // Snap to exact values first time after reset, then smooth for subsequent changes.
104 m_parameter1->resetSmoothedValue();
105 m_parameter2->resetSmoothedValue();
106 m_parameter3->resetSmoothedValue();
107 m_filterCoefficientsDirty = true;
108 m_hasJustReset = false;
109 } else {
110 // Smooth all of the filter parameters. If they haven't yet converged to their target value then mark coefficients as dirty.
111 bool isStable1 = m_parameter1->smooth();
112 bool isStable2 = m_parameter2->smooth();
113 bool isStable3 = m_parameter3->smooth();
114 if (!(isStable1 && isStable2 && isStable3))
115 m_filterCoefficientsDirty = true;
116 }
117
118 // For each channel of our input, process using the corresponding BiquadDSPKernel into the output channel.
119 for (unsigned i = 0; i < m_kernels.size(); ++i)
120 m_kernels[i]->process(source->channel(i)->data(), destination->channel(i)->data(), framesToProcess);
121 }
122
123 } // namespace WebCore
124
125 #endif // ENABLE(WEB_AUDIO)
126