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(AudioContext* context, float sampleRate, size_t numberOfChannels, bool autoInitialize)
36    : AudioDSPKernelProcessor(sampleRate, numberOfChannels)
37    , m_type(LowPass)
38    , m_parameter1(0)
39    , m_parameter2(0)
40    , m_parameter3(0)
41    , m_parameter4(0)
42    , m_filterCoefficientsDirty(true)
43    , m_hasSampleAccurateValues(false)
44{
45    double nyquist = 0.5 * this->sampleRate();
46
47    // Create parameters for BiquadFilterNode.
48    m_parameter1 = AudioParam::create(context, "frequency", 350.0, 10.0, nyquist);
49    m_parameter2 = AudioParam::create(context, "Q", 1, 0.0001, 1000.0);
50    m_parameter3 = AudioParam::create(context, "gain", 0.0, -40, 40);
51    m_parameter4 = AudioParam::create(context, "detune", 0.0, -4800, 4800);
52
53    if (autoInitialize)
54        initialize();
55}
56
57BiquadProcessor::~BiquadProcessor()
58{
59    if (isInitialized())
60        uninitialize();
61}
62
63std::unique_ptr<AudioDSPKernel> BiquadProcessor::createKernel()
64{
65    return std::make_unique<BiquadDSPKernel>(this);
66}
67
68void BiquadProcessor::checkForDirtyCoefficients()
69{
70    // Deal with smoothing / de-zippering. Start out assuming filter parameters are not changing.
71
72    // The BiquadDSPKernel objects rely on this value to see if they need to re-compute their internal filter coefficients.
73    m_filterCoefficientsDirty = false;
74    m_hasSampleAccurateValues = false;
75
76    if (m_parameter1->hasSampleAccurateValues() || m_parameter2->hasSampleAccurateValues() || m_parameter3->hasSampleAccurateValues() || m_parameter4->hasSampleAccurateValues()) {
77        m_filterCoefficientsDirty = true;
78        m_hasSampleAccurateValues = true;
79    } else {
80        if (m_hasJustReset) {
81            // Snap to exact values first time after reset, then smooth for subsequent changes.
82            m_parameter1->resetSmoothedValue();
83            m_parameter2->resetSmoothedValue();
84            m_parameter3->resetSmoothedValue();
85            m_parameter4->resetSmoothedValue();
86            m_filterCoefficientsDirty = true;
87            m_hasJustReset = false;
88        } else {
89            // Smooth all of the filter parameters. If they haven't yet converged to their target value then mark coefficients as dirty.
90            bool isStable1 = m_parameter1->smooth();
91            bool isStable2 = m_parameter2->smooth();
92            bool isStable3 = m_parameter3->smooth();
93            bool isStable4 = m_parameter4->smooth();
94            if (!(isStable1 && isStable2 && isStable3 && isStable4))
95                m_filterCoefficientsDirty = true;
96        }
97    }
98}
99
100void BiquadProcessor::process(const AudioBus* source, AudioBus* destination, size_t framesToProcess)
101{
102    if (!isInitialized()) {
103        destination->zero();
104        return;
105    }
106
107    checkForDirtyCoefficients();
108
109    // For each channel of our input, process using the corresponding BiquadDSPKernel into the output channel.
110    for (unsigned i = 0; i < m_kernels.size(); ++i)
111        m_kernels[i]->process(source->channel(i)->data(), destination->channel(i)->mutableData(), framesToProcess);
112}
113
114void BiquadProcessor::setType(FilterType type)
115{
116    if (type != m_type) {
117        m_type = type;
118        reset(); // The filter state must be reset only if the type has changed.
119    }
120}
121
122void BiquadProcessor::getFrequencyResponse(int nFrequencies,
123                                           const float* frequencyHz,
124                                           float* magResponse,
125                                           float* phaseResponse)
126{
127    // Compute the frequency response on a separate temporary kernel
128    // to avoid interfering with the processing running in the audio
129    // thread on the main kernels.
130
131    auto responseKernel = std::make_unique<BiquadDSPKernel>(this);
132
133    responseKernel->getFrequencyResponse(nFrequencies, frequencyHz, magResponse, phaseResponse);
134}
135
136} // namespace WebCore
137
138#endif // ENABLE(WEB_AUDIO)
139