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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 "config.h"
#if ENABLE(WEB_AUDIO)
#include "BiquadProcessor.h"
#include "BiquadDSPKernel.h"
namespace WebCore {
BiquadProcessor::BiquadProcessor(FilterType type, double 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();
switch (type) {
// Highpass and lowpass share the same parameters and only differ in filter type.
case LowPass2:
case HighPass2:
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;
case Peaking:
m_parameter1 = AudioParam::create("frequency", 2500.0, 20.0, nyquist);
m_parameter2 = AudioParam::create("gain", 0.0, -20.0, 20.0);
m_parameter3 = AudioParam::create("Q", 0.5, 0.0, 1000.0);
break;
case Allpass:
m_parameter1 = AudioParam::create("frequency", 2500.0, 20.0, nyquist);
m_parameter2 = AudioParam::create("Q", 0.5, 0.0, 1000.0);
m_parameter3 = AudioParam::create("unused", 0.0, 0.0, 1.0);
break;
case LowShelf:
m_parameter1 = AudioParam::create("frequency", 80.0, 20.0, nyquist);
m_parameter2 = AudioParam::create("gain", 0.0, 0.0, 1.0);
m_parameter3 = AudioParam::create("unused", 0.0, 0.0, 1.0);
break;
case HighShelf:
m_parameter1 = AudioParam::create("frequency", 10000.0, 20.0, nyquist);
m_parameter2 = AudioParam::create("gain", 0.0, 0.0, 1.0);
m_parameter3 = AudioParam::create("unused", 0.0, 0.0, 1.0);
break;
}
if (autoInitialize)
initialize();
}
BiquadProcessor::~BiquadProcessor()
{
if (isInitialized())
uninitialize();
}
PassOwnPtr<AudioDSPKernel> BiquadProcessor::createKernel()
{
return adoptPtr(new BiquadDSPKernel(this));
}
void BiquadProcessor::process(AudioBus* source, AudioBus* destination, size_t framesToProcess)
{
if (!isInitialized()) {
destination->zero();
return;
}
// 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;
}
// 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);
}
} // namespace WebCore
#endif // ENABLE(WEB_AUDIO)
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