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29 #include "BiquadProcessor.h"
31 #include "BiquadDSPKernel.h"
35 BiquadProcessor::BiquadProcessor(double sampleRate, size_t numberOfChannels, bool autoInitialize)
36 : AudioDSPKernelProcessor(sampleRate, numberOfChannels)
41 , m_filterCoefficientsDirty(true)
43 double nyquist = 0.5 * this->sampleRate();
45 // Create parameters for BiquadFilterNode.
46 m_parameter1 = AudioParam::create("frequency", 350.0, 10.0, nyquist);
47 m_parameter2 = AudioParam::create("Q", 1, 0.0001, 1000.0);
48 m_parameter3 = AudioParam::create("gain", 0.0, -40, 40);
54 BiquadProcessor::BiquadProcessor(FilterType type, double sampleRate, size_t numberOfChannels, bool autoInitialize)
55 : AudioDSPKernelProcessor(sampleRate, numberOfChannels)
60 , m_filterCoefficientsDirty(true)
62 double nyquist = 0.5 * this->sampleRate();
64 // Handle the deprecated LowPass2FilterNode and HighPass2FilterNode.
66 // Highpass and lowpass share the same parameters and only differ in filter type.
69 m_parameter1 = AudioParam::create("frequency", 350.0, 20.0, nyquist);
70 m_parameter2 = AudioParam::create("resonance", 0.0, -20.0, 20.0);
71 m_parameter3 = AudioParam::create("unused", 0.0, 0.0, 1.0);
82 BiquadProcessor::~BiquadProcessor()
88 PassOwnPtr<AudioDSPKernel> BiquadProcessor::createKernel()
90 return adoptPtr(new BiquadDSPKernel(this));
93 void BiquadProcessor::process(AudioBus* source, AudioBus* destination, size_t framesToProcess)
95 if (!isInitialized()) {
100 // Deal with smoothing / de-zippering. Start out assuming filter parameters are not changing.
101 // The BiquadDSPKernel objects rely on this value to see if they need to re-compute their internal filter coefficients.
102 m_filterCoefficientsDirty = false;
104 if (m_hasJustReset) {
105 // Snap to exact values first time after reset, then smooth for subsequent changes.
106 m_parameter1->resetSmoothedValue();
107 m_parameter2->resetSmoothedValue();
108 m_parameter3->resetSmoothedValue();
109 m_filterCoefficientsDirty = true;
110 m_hasJustReset = false;
112 // Smooth all of the filter parameters. If they haven't yet converged to their target value then mark coefficients as dirty.
113 bool isStable1 = m_parameter1->smooth();
114 bool isStable2 = m_parameter2->smooth();
115 bool isStable3 = m_parameter3->smooth();
116 if (!(isStable1 && isStable2 && isStable3))
117 m_filterCoefficientsDirty = true;
120 // For each channel of our input, process using the corresponding BiquadDSPKernel into the output channel.
121 for (unsigned i = 0; i < m_kernels.size(); ++i)
122 m_kernels[i]->process(source->channel(i)->data(), destination->channel(i)->data(), framesToProcess);
125 } // namespace WebCore
127 #endif // ENABLE(WEB_AUDIO)