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29 #include "modules/webaudio/BiquadProcessor.h"
31 #include "modules/webaudio/BiquadDSPKernel.h"
35 BiquadProcessor::BiquadProcessor(AudioContext* context, float sampleRate, size_t numberOfChannels, bool autoInitialize)
36 : AudioDSPKernelProcessor(sampleRate, numberOfChannels)
38 , m_parameter1(nullptr)
39 , m_parameter2(nullptr)
40 , m_parameter3(nullptr)
41 , m_parameter4(nullptr)
42 , m_filterCoefficientsDirty(true)
43 , m_hasSampleAccurateValues(false)
45 // Create parameters for BiquadFilterNode.
46 m_parameter1 = AudioParam::create(context, 350.0);
47 m_parameter2 = AudioParam::create(context, 1);
48 m_parameter3 = AudioParam::create(context, 0.0);
49 m_parameter4 = AudioParam::create(context, 0.0);
55 BiquadProcessor::~BiquadProcessor()
61 void BiquadProcessor::trace(Visitor* visitor)
63 visitor->trace(m_parameter1);
64 visitor->trace(m_parameter2);
65 visitor->trace(m_parameter3);
66 visitor->trace(m_parameter4);
67 AudioDSPKernelProcessor::trace(visitor);
70 PassOwnPtr<AudioDSPKernel> BiquadProcessor::createKernel()
72 return adoptPtr(new BiquadDSPKernel(this));
75 void BiquadProcessor::checkForDirtyCoefficients()
77 // Deal with smoothing / de-zippering. Start out assuming filter parameters are not changing.
79 // The BiquadDSPKernel objects rely on this value to see if they need to re-compute their internal filter coefficients.
80 m_filterCoefficientsDirty = false;
81 m_hasSampleAccurateValues = false;
83 if (m_parameter1->hasSampleAccurateValues() || m_parameter2->hasSampleAccurateValues() || m_parameter3->hasSampleAccurateValues() || m_parameter4->hasSampleAccurateValues()) {
84 m_filterCoefficientsDirty = true;
85 m_hasSampleAccurateValues = true;
88 // Snap to exact values first time after reset, then smooth for subsequent changes.
89 m_parameter1->resetSmoothedValue();
90 m_parameter2->resetSmoothedValue();
91 m_parameter3->resetSmoothedValue();
92 m_parameter4->resetSmoothedValue();
93 m_filterCoefficientsDirty = true;
94 m_hasJustReset = false;
96 // Smooth all of the filter parameters. If they haven't yet converged to their target value then mark coefficients as dirty.
97 bool isStable1 = m_parameter1->smooth();
98 bool isStable2 = m_parameter2->smooth();
99 bool isStable3 = m_parameter3->smooth();
100 bool isStable4 = m_parameter4->smooth();
101 if (!(isStable1 && isStable2 && isStable3 && isStable4))
102 m_filterCoefficientsDirty = true;
107 void BiquadProcessor::process(const AudioBus* source, AudioBus* destination, size_t framesToProcess)
109 if (!isInitialized()) {
114 checkForDirtyCoefficients();
116 // For each channel of our input, process using the corresponding BiquadDSPKernel into the output channel.
117 for (unsigned i = 0; i < m_kernels.size(); ++i)
118 m_kernels[i]->process(source->channel(i)->data(), destination->channel(i)->mutableData(), framesToProcess);
121 void BiquadProcessor::setType(FilterType type)
123 if (type != m_type) {
125 reset(); // The filter state must be reset only if the type has changed.
129 void BiquadProcessor::getFrequencyResponse(int nFrequencies,
130 const float* frequencyHz,
132 float* phaseResponse)
134 // Compute the frequency response on a separate temporary kernel
135 // to avoid interfering with the processing running in the audio
136 // thread on the main kernels.
138 OwnPtr<BiquadDSPKernel> responseKernel = adoptPtr(new BiquadDSPKernel(this));
140 responseKernel->getFrequencyResponse(nFrequencies, frequencyHz, magResponse, phaseResponse);
145 #endif // ENABLE(WEB_AUDIO)