/* * Copyright (C) 2010, Google Inc. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS'' AND ANY * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE * DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS BE LIABLE FOR ANY * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ #include "config.h" #if ENABLE(WEB_AUDIO) #include "BiquadProcessor.h" #include "BiquadDSPKernel.h" namespace WebCore { BiquadProcessor::BiquadProcessor(float sampleRate, size_t numberOfChannels, bool autoInitialize) : AudioDSPKernelProcessor(sampleRate, numberOfChannels) , m_type(LowPass) , m_parameter1(0) , m_parameter2(0) , m_parameter3(0) , m_filterCoefficientsDirty(true) { double nyquist = 0.5 * this->sampleRate(); // Create parameters for BiquadFilterNode. m_parameter1 = AudioParam::create("frequency", 350.0, 10.0, nyquist); m_parameter2 = AudioParam::create("Q", 1, 0.0001, 1000.0); m_parameter3 = AudioParam::create("gain", 0.0, -40, 40); if (autoInitialize) initialize(); } BiquadProcessor::BiquadProcessor(FilterType type, float sampleRate, size_t numberOfChannels, bool autoInitialize) : AudioDSPKernelProcessor(sampleRate, numberOfChannels) , m_type(type) , m_parameter1(0) , m_parameter2(0) , m_parameter3(0) , m_filterCoefficientsDirty(true) { double nyquist = 0.5 * this->sampleRate(); // Handle the deprecated LowPass2FilterNode and HighPass2FilterNode. switch (type) { // Highpass and lowpass share the same parameters and only differ in filter type. case LowPass: case HighPass: m_parameter1 = AudioParam::create("frequency", 350.0, 20.0, nyquist); m_parameter2 = AudioParam::create("resonance", 0.0, -20.0, 20.0); m_parameter3 = AudioParam::create("unused", 0.0, 0.0, 1.0); break; default: ASSERT_NOT_REACHED(); } if (autoInitialize) initialize(); } BiquadProcessor::~BiquadProcessor() { if (isInitialized()) uninitialize(); } PassOwnPtr BiquadProcessor::createKernel() { return adoptPtr(new BiquadDSPKernel(this)); } void BiquadProcessor::checkForDirtyCoefficients() { // Deal with smoothing / de-zippering. Start out assuming filter parameters are not changing. // The BiquadDSPKernel objects rely on this value to see if they need to re-compute their internal filter coefficients. m_filterCoefficientsDirty = false; if (m_hasJustReset) { // Snap to exact values first time after reset, then smooth for subsequent changes. m_parameter1->resetSmoothedValue(); m_parameter2->resetSmoothedValue(); m_parameter3->resetSmoothedValue(); m_filterCoefficientsDirty = true; m_hasJustReset = false; } else { // Smooth all of the filter parameters. If they haven't yet converged to their target value then mark coefficients as dirty. bool isStable1 = m_parameter1->smooth(); bool isStable2 = m_parameter2->smooth(); bool isStable3 = m_parameter3->smooth(); if (!(isStable1 && isStable2 && isStable3)) m_filterCoefficientsDirty = true; } } void BiquadProcessor::process(AudioBus* source, AudioBus* destination, size_t framesToProcess) { if (!isInitialized()) { destination->zero(); return; } checkForDirtyCoefficients(); // For each channel of our input, process using the corresponding BiquadDSPKernel into the output channel. for (unsigned i = 0; i < m_kernels.size(); ++i) m_kernels[i]->process(source->channel(i)->data(), destination->channel(i)->data(), framesToProcess); } void BiquadProcessor::setType(FilterType type) { if (type != m_type) { m_type = type; reset(); // The filter state must be reset only if the type has changed. } } void BiquadProcessor::getFrequencyResponse(int nFrequencies, const float* frequencyHz, float* magResponse, float* phaseResponse) { // Compute the frequency response on a separate temporary kernel // to avoid interfering with the processing running in the audio // thread on the main kernels. OwnPtr responseKernel = adoptPtr(new BiquadDSPKernel(this)); responseKernel->getFrequencyResponse(nFrequencies, frequencyHz, magResponse, phaseResponse); } } // namespace WebCore #endif // ENABLE(WEB_AUDIO)