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
33namespace WebCore {
34
35BiquadProcessor::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
80BiquadProcessor::~BiquadProcessor()
81{
82    if (isInitialized())
83        uninitialize();
84}
85
86PassOwnPtr<AudioDSPKernel> BiquadProcessor::createKernel()
87{
88    return adoptPtr(new BiquadDSPKernel(this));
89}
90
91void 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