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#include <QtDebug>
#include "engine/enginesidechaincompressor.h"
EngineSideChainCompressor::EngineSideChainCompressor(const QString& group)
: m_compressRatio(1.0),
m_bAboveThreshold(false),
m_threshold(1.0),
m_strength(1.0),
m_attackTime(0),
m_decayTime(0),
m_attackPerFrame(0.0),
m_decayPerFrame(0.0) {
Q_UNUSED(group);
}
void EngineSideChainCompressor::calculateRates() {
// Don't allow completely zero rates, or else if parameters change
// we might get stuck on a compression value.
if (m_attackTime == 0) {
// Attack really shouldn't be instant, but we allow it.
m_attackPerFrame = m_strength;
} else {
m_attackPerFrame = m_strength / m_attackTime;
}
if (m_decayTime == 0) {
m_decayPerFrame = m_strength;
} else {
m_decayPerFrame = m_strength / m_decayTime;
}
if (m_attackPerFrame <= 0) {
m_attackPerFrame = 0.005f;
}
if (m_decayPerFrame <= 0) {
m_decayPerFrame = 0.005f;
}
//qDebug() << "Compressor attack per frame: " << m_attackPerFrame
// << "decay per frame: " << m_decayPerFrame;
}
void EngineSideChainCompressor::setAboveThreshold(bool value) {
m_bAboveThreshold = value;
}
void EngineSideChainCompressor::processKey(const CSAMPLE* pIn, const int iBufferSize) {
m_bAboveThreshold = false;
for (int i = 0; i + 1 < iBufferSize; i += 2) {
CSAMPLE val = (pIn[i] + pIn[i + 1]) / 2;
if (val > m_threshold) {
m_bAboveThreshold = true;
return;
}
}
}
double EngineSideChainCompressor::calculateCompressedGain(int frames) {
if (m_bAboveThreshold) {
if (m_compressRatio > m_strength) {
m_compressRatio -= m_attackPerFrame * frames;
if (m_compressRatio < m_strength) {
// If we overshot, clamp.
m_compressRatio = m_strength;
}
} else if (m_compressRatio < m_strength) {
// If the strength param was changed, we might be compressing too much.
m_compressRatio += m_decayPerFrame * frames;
}
} else {
VERIFY_OR_DEBUG_ASSERT(m_compressRatio >= 0) {
qWarning() << "Programming error, below-zero compression detected.";
}
if (m_compressRatio < 1) {
m_compressRatio += m_decayPerFrame * frames;
if (m_compressRatio > 1) {
// If we overshot, clamp.
m_compressRatio = 1;
}
}
}
return m_compressRatio;
}
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