DynamicsCompressor.cpp [plain text]
#include "config.h"
#if ENABLE(WEB_AUDIO)
#include "DynamicsCompressor.h"
#include "AudioBus.h"
#include "AudioUtilities.h"
#include <wtf/MathExtras.h>
namespace WebCore {
using namespace AudioUtilities;
DynamicsCompressor::DynamicsCompressor(float sampleRate, unsigned numberOfChannels)
: m_numberOfChannels(numberOfChannels)
, m_sampleRate(sampleRate)
, m_compressor(sampleRate, numberOfChannels)
{
m_lastFilterStageRatio = -1;
m_lastAnchor = -1;
m_lastFilterStageGain = -1;
setNumberOfChannels(numberOfChannels);
initializeParameters();
}
void DynamicsCompressor::setParameterValue(unsigned parameterID, float value)
{
ASSERT(parameterID < ParamLast);
if (parameterID < ParamLast)
m_parameters[parameterID] = value;
}
void DynamicsCompressor::initializeParameters()
{
m_parameters[ParamThreshold] = -24; m_parameters[ParamKnee] = 30; m_parameters[ParamRatio] = 12; m_parameters[ParamAttack] = 0.003f; m_parameters[ParamRelease] = 0.250f; m_parameters[ParamPreDelay] = 0.006f;
m_parameters[ParamReleaseZone1] = 0.09f;
m_parameters[ParamReleaseZone2] = 0.16f;
m_parameters[ParamReleaseZone3] = 0.42f;
m_parameters[ParamReleaseZone4] = 0.98f;
m_parameters[ParamFilterStageGain] = 4.4f; m_parameters[ParamFilterStageRatio] = 2;
m_parameters[ParamFilterAnchor] = 15000 / nyquist();
m_parameters[ParamPostGain] = 0; m_parameters[ParamReduction] = 0;
m_parameters[ParamEffectBlend] = 1;
}
float DynamicsCompressor::parameterValue(unsigned parameterID)
{
ASSERT(parameterID < ParamLast);
return m_parameters[parameterID];
}
void DynamicsCompressor::setEmphasisStageParameters(unsigned stageIndex, float gain, float normalizedFrequency )
{
float gk = 1 - gain / 20;
float f1 = normalizedFrequency * gk;
float f2 = normalizedFrequency / gk;
float r1 = expf(-f1 * piFloat);
float r2 = expf(-f2 * piFloat);
ASSERT(m_numberOfChannels == m_preFilterPacks.size());
for (unsigned i = 0; i < m_numberOfChannels; ++i) {
ZeroPole& preFilter = m_preFilterPacks[i]->filters[stageIndex];
preFilter.setZero(r1);
preFilter.setPole(r2);
ZeroPole& postFilter = m_postFilterPacks[i]->filters[stageIndex];
postFilter.setZero(r2);
postFilter.setPole(r1);
}
}
void DynamicsCompressor::setEmphasisParameters(float gain, float anchorFreq, float filterStageRatio)
{
setEmphasisStageParameters(0, gain, anchorFreq);
setEmphasisStageParameters(1, gain, anchorFreq / filterStageRatio);
setEmphasisStageParameters(2, gain, anchorFreq / (filterStageRatio * filterStageRatio));
setEmphasisStageParameters(3, gain, anchorFreq / (filterStageRatio * filterStageRatio * filterStageRatio));
}
void DynamicsCompressor::process(const AudioBus* sourceBus, AudioBus* destinationBus, unsigned framesToProcess)
{
unsigned numberOfChannels = destinationBus->numberOfChannels();
unsigned numberOfSourceChannels = sourceBus->numberOfChannels();
ASSERT(numberOfChannels == m_numberOfChannels && numberOfSourceChannels);
if (numberOfChannels != m_numberOfChannels || !numberOfSourceChannels) {
destinationBus->zero();
return;
}
switch (numberOfChannels) {
case 2: m_sourceChannels[0] = sourceBus->channel(0)->data();
if (numberOfSourceChannels > 1)
m_sourceChannels[1] = sourceBus->channel(1)->data();
else
m_sourceChannels[1] = m_sourceChannels[0];
break;
default:
ASSERT_NOT_REACHED();
destinationBus->zero();
return;
}
for (unsigned i = 0; i < numberOfChannels; ++i)
m_destinationChannels[i] = destinationBus->channel(i)->mutableData();
float filterStageGain = parameterValue(ParamFilterStageGain);
float filterStageRatio = parameterValue(ParamFilterStageRatio);
float anchor = parameterValue(ParamFilterAnchor);
if (filterStageGain != m_lastFilterStageGain || filterStageRatio != m_lastFilterStageRatio || anchor != m_lastAnchor) {
m_lastFilterStageGain = filterStageGain;
m_lastFilterStageRatio = filterStageRatio;
m_lastAnchor = anchor;
setEmphasisParameters(filterStageGain, anchor, filterStageRatio);
}
for (unsigned i = 0; i < numberOfChannels; ++i) {
const float* sourceData = m_sourceChannels[i];
float* destinationData = m_destinationChannels[i];
ZeroPole* preFilters = m_preFilterPacks[i]->filters;
preFilters[0].process(sourceData, destinationData, framesToProcess);
preFilters[1].process(destinationData, destinationData, framesToProcess);
preFilters[2].process(destinationData, destinationData, framesToProcess);
preFilters[3].process(destinationData, destinationData, framesToProcess);
}
float dbThreshold = parameterValue(ParamThreshold);
float dbKnee = parameterValue(ParamKnee);
float ratio = parameterValue(ParamRatio);
float attackTime = parameterValue(ParamAttack);
float releaseTime = parameterValue(ParamRelease);
float preDelayTime = parameterValue(ParamPreDelay);
float dbPostGain = parameterValue(ParamPostGain);
float effectBlend = parameterValue(ParamEffectBlend);
float releaseZone1 = parameterValue(ParamReleaseZone1);
float releaseZone2 = parameterValue(ParamReleaseZone2);
float releaseZone3 = parameterValue(ParamReleaseZone3);
float releaseZone4 = parameterValue(ParamReleaseZone4);
m_compressor.process(m_destinationChannels.get(),
m_destinationChannels.get(),
numberOfChannels,
framesToProcess,
dbThreshold,
dbKnee,
ratio,
attackTime,
releaseTime,
preDelayTime,
dbPostGain,
effectBlend,
releaseZone1,
releaseZone2,
releaseZone3,
releaseZone4
);
setParameterValue(ParamReduction, m_compressor.meteringGain());
for (unsigned i = 0; i < numberOfChannels; ++i) {
float* destinationData = m_destinationChannels[i];
ZeroPole* postFilters = m_postFilterPacks[i]->filters;
postFilters[0].process(destinationData, destinationData, framesToProcess);
postFilters[1].process(destinationData, destinationData, framesToProcess);
postFilters[2].process(destinationData, destinationData, framesToProcess);
postFilters[3].process(destinationData, destinationData, framesToProcess);
}
}
void DynamicsCompressor::reset()
{
m_lastFilterStageRatio = -1; m_lastAnchor = -1;
m_lastFilterStageGain = -1;
for (unsigned channel = 0; channel < m_numberOfChannels; ++channel) {
for (unsigned stageIndex = 0; stageIndex < 4; ++stageIndex) {
m_preFilterPacks[channel]->filters[stageIndex].reset();
m_postFilterPacks[channel]->filters[stageIndex].reset();
}
}
m_compressor.reset();
}
void DynamicsCompressor::setNumberOfChannels(unsigned numberOfChannels)
{
if (m_preFilterPacks.size() == numberOfChannels)
return;
m_preFilterPacks.clear();
m_postFilterPacks.clear();
for (unsigned i = 0; i < numberOfChannels; ++i) {
m_preFilterPacks.append(adoptPtr(new ZeroPoleFilterPack4()));
m_postFilterPacks.append(adoptPtr(new ZeroPoleFilterPack4()));
}
m_sourceChannels = adoptArrayPtr(new const float* [numberOfChannels]);
m_destinationChannels = adoptArrayPtr(new float* [numberOfChannels]);
m_compressor.setNumberOfChannels(numberOfChannels);
m_numberOfChannels = numberOfChannels;
}
}
#endif // ENABLE(WEB_AUDIO)