void EffectNoiseRemoval::Cleanup()
{
int i;
EndFFT(hFFT);
if (mDoProfile) {
ApplyFreqSmoothing(mNoiseThreshold);
}
for(i = 0; i < mHistoryLen; i++) {
delete[] mSpectrums[i];
delete[] mGains[i];
delete[] mRealFFTs[i];
delete[] mImagFFTs[i];
}
delete[] mSpectrums;
delete[] mGains;
delete[] mRealFFTs;
delete[] mImagFFTs;
delete[] mFFTBuffer;
delete[] mInWaveBuffer;
delete[] mWindow;
delete[] mOutImagBuffer;
delete[] mOutOverlapBuffer;
}
void EffectNoiseRemoval::RemoveNoise()
{
int center = mHistoryLen / 2;
int start = center - mMinSignalBlocks/2;
int finish = start + mMinSignalBlocks;
int i, j;
// Raise the gain for elements in the center of the sliding history
for (j = 0; j < mSpectrumSize; j++) {
float min = mSpectrums[start][j];
for (i = start+1; i < finish; i++) {
if (mSpectrums[i][j] < min)
min = mSpectrums[i][j];
}
if (min > mNoiseThreshold[j] && mGains[center][j] < 0.0)
mGains[center][j] = 0.0;
}
// Decay the gain in both directions;
// note that mOneBlockAttackDecay is a negative number, like -1.0
// dB of attenuation per block
for (j = 0; j < mSpectrumSize; j++) {
for (i = center + 1; i < mHistoryLen; i++) {
if (mGains[i][j] < mGains[i - 1][j] + mOneBlockAttackDecay)
mGains[i][j] = mGains[i - 1][j] + mOneBlockAttackDecay;
if (mGains[i][j] < mNoiseGain)
mGains[i][j] = mNoiseGain;
}
for (i = center - 1; i >= 0; i--) {
if (mGains[i][j] < mGains[i + 1][j] + mOneBlockAttackDecay)
mGains[i][j] = mGains[i + 1][j] + mOneBlockAttackDecay;
if (mGains[i][j] < mNoiseGain)
mGains[i][j] = mNoiseGain;
}
}
// Apply frequency smoothing to output gain
int out = mHistoryLen - 1; // end of the queue
ApplyFreqSmoothing(mGains[out]);
// Apply gain to FFT
for (j = 0; j < mSpectrumSize; j++) {
float mult = pow(10.0, mGains[out][j] / 20.0);
mRealFFTs[out][j] *= mult;
mImagFFTs[out][j] *= mult;
if (j > 0 && j < mSpectrumSize - 1) {
mRealFFTs[out][mWindowSize - j] *= mult;
mImagFFTs[out][mWindowSize - j] *= mult;
}
}
// Invert the FFT into the output buffer
FFT(mWindowSize, true, mRealFFTs[out], mImagFFTs[out],
mOutWaveBuffer, mOutImagBuffer);
// Hanning window
WindowFunc(3, mWindowSize, mOutWaveBuffer);
// Overlap-add
for(j = 0; j < mWindowSize; j++)
mOutOverlapBuffer[j] += mOutWaveBuffer[j];
// Output the first half of the overlap buffer, they're done -
// and then shift the next half over.
if (mOutSampleCount >= 0) { // ...but not if it's the first half-window
mOutputTrack->Append((samplePtr)mOutOverlapBuffer, floatSample,
mWindowSize / 2);
}
mOutSampleCount += mWindowSize / 2;
for(j = 0; j < mWindowSize / 2; j++) {
mOutOverlapBuffer[j] = mOutOverlapBuffer[j + (mWindowSize / 2)];
mOutOverlapBuffer[j + (mWindowSize / 2)] = 0.0;
}
}
void EffectNoiseRemoval::RemoveNoise()
{
int center = mHistoryLen / 2;
int start = center - mMinSignalBlocks/2;
int finish = start + mMinSignalBlocks;
int i, j;
// Raise the gain for elements in the center of the sliding history
for (j = 0; j < mSpectrumSize; j++) {
float min = mSpectrums[start][j];
for (i = start+1; i < finish; i++) {
if (mSpectrums[i][j] < min)
min = mSpectrums[i][j];
}
if (min > mSensitivityFactor * mNoiseThreshold[j] && mGains[center][j] < 1.0) {
if (mbLeaveNoise) mGains[center][j] = 0.0;
else mGains[center][j] = 1.0;
} else {
if (mbLeaveNoise) mGains[center][j] = 1.0;
}
}
// Decay the gain in both directions;
// note that mOneBlockAttackDecay is less than 1.0
// of linear attenuation per block
for (j = 0; j < mSpectrumSize; j++) {
for (i = center + 1; i < mHistoryLen; i++) {
if (mGains[i][j] < mGains[i - 1][j] * mOneBlockAttackDecay)
mGains[i][j] = mGains[i - 1][j] * mOneBlockAttackDecay;
if (mGains[i][j] < mNoiseAttenFactor)
mGains[i][j] = mNoiseAttenFactor;
}
for (i = center - 1; i >= 0; i--) {
if (mGains[i][j] < mGains[i + 1][j] * mOneBlockAttackDecay)
mGains[i][j] = mGains[i + 1][j] * mOneBlockAttackDecay;
if (mGains[i][j] < mNoiseAttenFactor)
mGains[i][j] = mNoiseAttenFactor;
}
}
// Apply frequency smoothing to output gain
int out = mHistoryLen - 1; // end of the queue
ApplyFreqSmoothing(mGains[out]);
// Apply gain to FFT
for (j = 0; j < (mSpectrumSize-1); j++) {
mFFTBuffer[j*2 ] = mRealFFTs[out][j] * mGains[out][j];
mFFTBuffer[j*2+1] = mImagFFTs[out][j] * mGains[out][j];
}
// The Fs/2 component is stored as the imaginary part of the DC component
mFFTBuffer[1] = mRealFFTs[out][mSpectrumSize-1] * mGains[out][mSpectrumSize-1];
// Invert the FFT into the output buffer
InverseRealFFTf(mFFTBuffer, hFFT);
// Overlap-add
for(j = 0; j < (mSpectrumSize-1); j++) {
mOutOverlapBuffer[j*2 ] += mFFTBuffer[hFFT->BitReversed[j] ] * mWindow[j*2 ];
mOutOverlapBuffer[j*2+1] += mFFTBuffer[hFFT->BitReversed[j]+1] * mWindow[j*2+1];
}
// Output the first half of the overlap buffer, they're done -
// and then shift the next half over.
if (mOutSampleCount >= 0) { // ...but not if it's the first half-window
mOutputTrack->Append((samplePtr)mOutOverlapBuffer, floatSample,
mWindowSize / 2);
}
mOutSampleCount += mWindowSize / 2;
for(j = 0; j < mWindowSize / 2; j++) {
mOutOverlapBuffer[j] = mOutOverlapBuffer[j + (mWindowSize / 2)];
mOutOverlapBuffer[j + (mWindowSize / 2)] = 0.0;
}
}
