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/*
* Copyright (C) 2011, 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 "WaveShaperDSPKernel.h"
#include "WaveShaperProcessor.h"
#include <algorithm>
#include <wtf/MainThread.h>
#include <wtf/Threading.h>
const unsigned RenderingQuantum = 128;
namespace WebCore {
WaveShaperDSPKernel::WaveShaperDSPKernel(WaveShaperProcessor* processor)
: AudioDSPKernel(processor)
{
if (processor->oversample() != WaveShaperProcessor::OverSampleNone)
lazyInitializeOversampling();
}
void WaveShaperDSPKernel::lazyInitializeOversampling()
{
ASSERT(isMainThread());
if (!m_tempBuffer) {
m_tempBuffer = std::make_unique<AudioFloatArray>(RenderingQuantum * 2);
m_tempBuffer2 = std::make_unique<AudioFloatArray>(RenderingQuantum * 4);
m_upSampler = std::make_unique<UpSampler>(RenderingQuantum);
m_downSampler = std::make_unique<DownSampler>(RenderingQuantum * 2);
m_upSampler2 = std::make_unique<UpSampler>(RenderingQuantum * 2);
m_downSampler2 = std::make_unique<DownSampler>(RenderingQuantum * 4);
}
}
void WaveShaperDSPKernel::process(const float* source, float* destination, size_t framesToProcess)
{
switch (waveShaperProcessor()->oversample()) {
case WaveShaperProcessor::OverSampleNone:
processCurve(source, destination, framesToProcess);
break;
case WaveShaperProcessor::OverSample2x:
processCurve2x(source, destination, framesToProcess);
break;
case WaveShaperProcessor::OverSample4x:
processCurve4x(source, destination, framesToProcess);
break;
default:
ASSERT_NOT_REACHED();
}
}
void WaveShaperDSPKernel::processCurve(const float* source, float* destination, size_t framesToProcess)
{
ASSERT(source && destination && waveShaperProcessor());
Float32Array* curve = waveShaperProcessor()->curve();
if (!curve) {
// Act as "straight wire" pass-through if no curve is set.
memcpy(destination, source, sizeof(float) * framesToProcess);
return;
}
float* curveData = curve->data();
int curveLength = curve->length();
ASSERT(curveData);
if (!curveData || !curveLength) {
memcpy(destination, source, sizeof(float) * framesToProcess);
return;
}
// Apply waveshaping curve.
for (unsigned i = 0; i < framesToProcess; ++i) {
const float input = source[i];
// Calculate a virtual index based on input -1 -> +1 with 0 being at the center of the curve data.
// Then linearly interpolate between the two points in the curve.
double virtualIndex = 0.5 * (input + 1) * curveLength;
int index1 = static_cast<int>(virtualIndex);
int index2 = index1 + 1;
double interpolationFactor = virtualIndex - index1;
// Clip index to the input range of the curve.
// This takes care of input outside of nominal range -1 -> +1
index1 = std::max(index1, 0);
index1 = std::min(index1, curveLength - 1);
index2 = std::max(index2, 0);
index2 = std::min(index2, curveLength - 1);
double value1 = curveData[index1];
double value2 = curveData[index2];
double output = (1.0 - interpolationFactor) * value1 + interpolationFactor * value2;
destination[i] = output;
}
}
void WaveShaperDSPKernel::processCurve2x(const float* source, float* destination, size_t framesToProcess)
{
bool isSafe = framesToProcess == RenderingQuantum;
ASSERT(isSafe);
if (!isSafe)
return;
float* tempP = m_tempBuffer->data();
m_upSampler->process(source, tempP, framesToProcess);
// Process at 2x up-sampled rate.
processCurve(tempP, tempP, framesToProcess * 2);
m_downSampler->process(tempP, destination, framesToProcess * 2);
}
void WaveShaperDSPKernel::processCurve4x(const float* source, float* destination, size_t framesToProcess)
{
bool isSafe = framesToProcess == RenderingQuantum;
ASSERT(isSafe);
if (!isSafe)
return;
float* tempP = m_tempBuffer->data();
float* tempP2 = m_tempBuffer2->data();
m_upSampler->process(source, tempP, framesToProcess);
m_upSampler2->process(tempP, tempP2, framesToProcess * 2);
// Process at 4x up-sampled rate.
processCurve(tempP2, tempP2, framesToProcess * 4);
m_downSampler2->process(tempP2, tempP, framesToProcess * 4);
m_downSampler->process(tempP, destination, framesToProcess * 2);
}
void WaveShaperDSPKernel::reset()
{
if (m_upSampler) {
m_upSampler->reset();
m_downSampler->reset();
m_upSampler2->reset();
m_downSampler2->reset();
}
}
double WaveShaperDSPKernel::latencyTime() const
{
size_t latencyFrames = 0;
WaveShaperDSPKernel* kernel = const_cast<WaveShaperDSPKernel*>(this);
switch (kernel->waveShaperProcessor()->oversample()) {
case WaveShaperProcessor::OverSampleNone:
break;
case WaveShaperProcessor::OverSample2x:
latencyFrames += m_upSampler->latencyFrames();
latencyFrames += m_downSampler->latencyFrames();
break;
case WaveShaperProcessor::OverSample4x:
{
// Account for first stage upsampling.
latencyFrames += m_upSampler->latencyFrames();
latencyFrames += m_downSampler->latencyFrames();
// Account for second stage upsampling.
// and divide by 2 to get back down to the regular sample-rate.
size_t latencyFrames2 = (m_upSampler2->latencyFrames() + m_downSampler2->latencyFrames()) / 2;
latencyFrames += latencyFrames2;
break;
}
default:
ASSERT_NOT_REACHED();
}
return static_cast<double>(latencyFrames) / sampleRate();
}
} // namespace WebCore
#endif // ENABLE(WEB_AUDIO)
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