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/*
* 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 "modules/webaudio/BiquadProcessor.h"
#include "modules/webaudio/BiquadDSPKernel.h"
namespace blink {
BiquadProcessor::BiquadProcessor(float sampleRate, size_t numberOfChannels, AudioParamHandler& frequency, AudioParamHandler& q, AudioParamHandler& gain, AudioParamHandler& detune)
: AudioDSPKernelProcessor(sampleRate, numberOfChannels)
, m_type(LowPass)
, m_parameter1(frequency)
, m_parameter2(q)
, m_parameter3(gain)
, m_parameter4(detune)
, m_filterCoefficientsDirty(true)
, m_hasSampleAccurateValues(false)
{
}
BiquadProcessor::~BiquadProcessor()
{
if (isInitialized())
uninitialize();
}
PassOwnPtr<AudioDSPKernel> 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;
m_hasSampleAccurateValues = false;
if (m_parameter1->hasSampleAccurateValues() || m_parameter2->hasSampleAccurateValues() || m_parameter3->hasSampleAccurateValues() || m_parameter4->hasSampleAccurateValues()) {
m_filterCoefficientsDirty = true;
m_hasSampleAccurateValues = true;
} else {
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_parameter4->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();
bool isStable4 = m_parameter4->smooth();
if (!(isStable1 && isStable2 && isStable3 && isStable4))
m_filterCoefficientsDirty = true;
}
}
}
void BiquadProcessor::process(const 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)->mutableData(), 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<BiquadDSPKernel> responseKernel = adoptPtr(new BiquadDSPKernel(this));
responseKernel->getFrequencyResponse(nFrequencies, frequencyHz, magResponse, phaseResponse);
}
} // namespace blink
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