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Merge pull request #57985 from Pineapple/pitchshift-tweaks
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PitchShift effect quality and performance tweaks for different pitch scale values
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@akien-mga
akien-mga authored Feb 14, 2022
2 parents 48ed040 + 29b6ed9 commit f45feda
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Showing 2 changed files with 81 additions and 56 deletions.
96 changes: 61 additions & 35 deletions servers/audio/effects/audio_effect_pitch_shift.cpp
View file
Original file line number Diff line number Diff line change
Expand Up @@ -74,7 +74,7 @@
*
*****************************************************************************/

void SMBPitchShift::PitchShift(float pitchShift, long numSampsToProcess, long fftFrameSize, long osamp, float sampleRate, float *indata, float *outdata,int stride) {
void SMBPitchShift::PitchShift(float pitchShift, int64_t numSampsToProcess, int64_t fftFrameSize, int64_t osamp, float sampleRate, float *indata, float *outdata,int stride) {


/*
Expand All @@ -85,19 +85,32 @@ void SMBPitchShift::PitchShift(float pitchShift, long numSampsToProcess, long ff
*/

double magn, phase, tmp, window, real, imag;
double freqPerBin, expct;
long i,k, qpd, index, inFifoLatency, stepSize, fftFrameSize2;
double freqPerBin, expct, reciprocalFftFrameSize;
int64_t i,k, qpd, index, inFifoLatency, stepSize, fftFrameSize2;

/* set up some handy variables */
fftFrameSize2 = fftFrameSize/2;
reciprocalFftFrameSize = 1./fftFrameSize;
stepSize = fftFrameSize/osamp;
freqPerBin = sampleRate/(double)fftFrameSize;
expct = 2.*Math_PI*(double)stepSize/(double)fftFrameSize;
freqPerBin = reciprocalFftFrameSize * sampleRate;
expct = Math_TAU * reciprocalFftFrameSize * stepSize;
inFifoLatency = fftFrameSize-stepSize;
if (gRover == 0) { gRover = inFifoLatency;
}
if (gRover == 0) {
gRover = inFifoLatency;
}

/* initialize our static arrays */
// If pitchShift changes clear arrays to prevent some artifacts and quality loss.
if (lastPitchShift != pitchShift) {
lastPitchShift = pitchShift;
memset(gInFIFO, 0, MAX_FRAME_LENGTH * sizeof(float));
memset(gOutFIFO, 0, MAX_FRAME_LENGTH * sizeof(float));
memset(gFFTworksp, 0, 2 * MAX_FRAME_LENGTH * sizeof(double));
memset(gLastPhase, 0, (MAX_FRAME_LENGTH / 2 + 1) * sizeof(double));
memset(gSumPhase, 0, (MAX_FRAME_LENGTH / 2 + 1) * sizeof(double));
memset(gOutputAccum, 0, 2 * MAX_FRAME_LENGTH * sizeof(double));
memset(gAnaFreq, 0, MAX_FRAME_LENGTH * sizeof(double));
memset(gAnaMagn, 0, MAX_FRAME_LENGTH * sizeof(double));
}

/* main processing loop */
for (i = 0; i < numSampsToProcess; i++){
Expand All @@ -112,7 +125,7 @@ void SMBPitchShift::PitchShift(float pitchShift, long numSampsToProcess, long ff

/* do windowing and re,im interleave */
for (k = 0; k < fftFrameSize;k++) {
window = -.5*cos(2.*Math_PI*(double)k/(double)fftFrameSize)+.5;
window = -.5*cos(Math_TAU * reciprocalFftFrameSize * k)+.5;
gFFTworksp[2*k] = gInFIFO[k] * window;
gFFTworksp[2*k+1] = 0.;
}
Expand All @@ -124,6 +137,7 @@ void SMBPitchShift::PitchShift(float pitchShift, long numSampsToProcess, long ff

/* this is the analysis step */
for (k = 0; k <= fftFrameSize2; k++) {

/* de-interlace FFT buffer */
real = gFFTworksp[2*k];
imag = gFFTworksp[2*k+1];
Expand All @@ -141,13 +155,15 @@ void SMBPitchShift::PitchShift(float pitchShift, long numSampsToProcess, long ff

/* map delta phase into +/- Pi interval */
qpd = tmp/Math_PI;
if (qpd >= 0) { qpd += qpd&1;
} else { qpd -= qpd&1;
}
if (qpd >= 0) {
qpd += qpd&1;
} else {
qpd -= qpd&1;
}
tmp -= Math_PI*(double)qpd;

/* get deviation from bin frequency from the +/- Pi interval */
tmp = osamp*tmp/(2.*Math_PI);
tmp = osamp*tmp/Math_TAU;

/* compute the k-th partials' true frequency */
tmp = (double)k*freqPerBin + tmp*freqPerBin;
Expand All @@ -160,8 +176,8 @@ void SMBPitchShift::PitchShift(float pitchShift, long numSampsToProcess, long ff

/* ***************** PROCESSING ******************* */
/* this does the actual pitch shifting */
memset(gSynMagn, 0, fftFrameSize*sizeof(float));
memset(gSynFreq, 0, fftFrameSize*sizeof(float));
memset(gSynMagn, 0, fftFrameSize*sizeof(double));
memset(gSynFreq, 0, fftFrameSize*sizeof(double));
for (k = 0; k <= fftFrameSize2; k++) {
index = k*pitchShift;
if (index <= fftFrameSize2) {
Expand All @@ -184,7 +200,7 @@ void SMBPitchShift::PitchShift(float pitchShift, long numSampsToProcess, long ff
tmp /= freqPerBin;

/* take osamp into account */
tmp = 2.*Math_PI*tmp/osamp;
tmp = Math_TAU*tmp/osamp;

/* add the overlap phase advance back in */
tmp += (double)k*expct;
Expand All @@ -199,33 +215,35 @@ void SMBPitchShift::PitchShift(float pitchShift, long numSampsToProcess, long ff
}

/* zero negative frequencies */
for (k = fftFrameSize+2; k < 2*fftFrameSize; k++) { gFFTworksp[k] = 0.;
}
for (k = fftFrameSize+2; k < 2*MAX_FRAME_LENGTH; k++) {
gFFTworksp[k] = 0.;
}

/* do inverse transform */
smbFft(gFFTworksp, fftFrameSize, 1);

/* do windowing and add to output accumulator */
for(k=0; k < fftFrameSize; k++) {
window = -.5*cos(2.*Math_PI*(double)k/(double)fftFrameSize)+.5;
window = -.5*cos(Math_TAU * reciprocalFftFrameSize * k)+.5;
gOutputAccum[k] += 2.*window*gFFTworksp[2*k]/(fftFrameSize2*osamp);
}
for (k = 0; k < stepSize; k++) { gOutFIFO[k] = gOutputAccum[k];
}
for (k = 0; k < stepSize; k++) {
gOutFIFO[k] = gOutputAccum[k];
}

/* shift accumulator */
memmove(gOutputAccum, gOutputAccum+stepSize, fftFrameSize*sizeof(float));
memmove(gOutputAccum, gOutputAccum+stepSize, fftFrameSize*sizeof(double));

/* move input FIFO */
for (k = 0; k < inFifoLatency; k++) { gInFIFO[k] = gInFIFO[k+stepSize];
}
for (k = 0; k < inFifoLatency; k++) {
gInFIFO[k] = gInFIFO[k+stepSize];
}
}
}
}



void SMBPitchShift::smbFft(float *fftBuffer, long fftFrameSize, long sign)
void SMBPitchShift::smbFft(double *fftBuffer, int64_t fftFrameSize, int64_t sign)
/*
FFT routine, (C)1996 S.M.Bernsee. Sign = -1 is FFT, 1 is iFFT (inverse)
Fills fftBuffer[0...2*fftFrameSize-1] with the Fourier transform of the
Expand All @@ -238,14 +256,16 @@ void SMBPitchShift::smbFft(float *fftBuffer, long fftFrameSize, long sign)
of the frequencies of interest is in fftBuffer[0...fftFrameSize].
*/
{
float wr, wi, arg, *p1, *p2, temp;
float tr, ti, ur, ui, *p1r, *p1i, *p2r, *p2i;
long i, bitm, j, le, le2, k;
double wr, wi, arg, *p1, *p2, temp;
double tr, ti, ur, ui, *p1r, *p1i, *p2r, *p2i;
int64_t i, bitm, j, le, le2, k, logN;
logN = (int64_t)(log(fftFrameSize) / log(2.) + .5);

for (i = 2; i < 2*fftFrameSize-2; i += 2) {
for (bitm = 2, j = 0; bitm < 2*fftFrameSize; bitm <<= 1) {
if (i & bitm) { j++;
}
if (i & bitm) {
j++;
}
j <<= 1;
}
if (i < j) {
Expand All @@ -255,7 +275,8 @@ void SMBPitchShift::smbFft(float *fftBuffer, long fftFrameSize, long sign)
*p1 = *p2; *p2 = temp;
}
}
for (k = 0, le = 2; k < (long)(log((double)fftFrameSize)/log(2.)+.5); k++) {

for (k = 0, le = 2; k < logN; k++) {
le <<= 1;
le2 = le>>1;
ur = 1.0;
Expand Down Expand Up @@ -288,6 +309,14 @@ void SMBPitchShift::smbFft(float *fftBuffer, long fftFrameSize, long sign)
void AudioEffectPitchShiftInstance::process(const AudioFrame *p_src_frames, AudioFrame *p_dst_frames, int p_frame_count) {
float sample_rate = AudioServer::get_singleton()->get_mix_rate();

// For pitch_scale 1.0 it's cheaper to just pass samples without processing them.
if (Math::is_equal_approx(base->pitch_scale, 1.0f)) {
for (int i = 0; i < p_frame_count; i++) {
p_dst_frames[i] = p_src_frames[i];
}
return;
}

float *in_l = (float *)p_src_frames;
float *in_r = in_l + 1;

Expand Down Expand Up @@ -361,7 +390,4 @@ AudioEffectPitchShift::AudioEffectPitchShift() {
pitch_scale = 1.0;
oversampling = 4;
fft_size = FFT_SIZE_2048;
wet = 0.0;
dry = 0.0;
filter = false;
}
41 changes: 20 additions & 21 deletions servers/audio/effects/audio_effect_pitch_shift.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -40,31 +40,33 @@ class SMBPitchShift {

float gInFIFO[MAX_FRAME_LENGTH];
float gOutFIFO[MAX_FRAME_LENGTH];
float gFFTworksp[2 * MAX_FRAME_LENGTH];
float gLastPhase[MAX_FRAME_LENGTH / 2 + 1];
float gSumPhase[MAX_FRAME_LENGTH / 2 + 1];
float gOutputAccum[2 * MAX_FRAME_LENGTH];
float gAnaFreq[MAX_FRAME_LENGTH];
float gAnaMagn[MAX_FRAME_LENGTH];
float gSynFreq[MAX_FRAME_LENGTH];
float gSynMagn[MAX_FRAME_LENGTH];
long gRover;

void smbFft(float *fftBuffer, long fftFrameSize, long sign);
double gFFTworksp[2 * MAX_FRAME_LENGTH];
double gLastPhase[MAX_FRAME_LENGTH / 2 + 1];
double gSumPhase[MAX_FRAME_LENGTH / 2 + 1];
double gOutputAccum[2 * MAX_FRAME_LENGTH];
double gAnaFreq[MAX_FRAME_LENGTH];
double gAnaMagn[MAX_FRAME_LENGTH];
double gSynFreq[MAX_FRAME_LENGTH];
double gSynMagn[MAX_FRAME_LENGTH];
int64_t gRover;
float lastPitchShift;

void smbFft(double *fftBuffer, int64_t fftFrameSize, int64_t sign);

public:
void PitchShift(float pitchShift, long numSampsToProcess, long fftFrameSize, long osamp, float sampleRate, float *indata, float *outdata, int stride);
void PitchShift(float pitchShift, int64_t numSampsToProcess, int64_t fftFrameSize, int64_t osamp, float sampleRate, float *indata, float *outdata, int stride);

SMBPitchShift() {
gRover = 0;
memset(gInFIFO, 0, MAX_FRAME_LENGTH * sizeof(float));
memset(gOutFIFO, 0, MAX_FRAME_LENGTH * sizeof(float));
memset(gFFTworksp, 0, 2 * MAX_FRAME_LENGTH * sizeof(float));
memset(gLastPhase, 0, (MAX_FRAME_LENGTH / 2 + 1) * sizeof(float));
memset(gSumPhase, 0, (MAX_FRAME_LENGTH / 2 + 1) * sizeof(float));
memset(gOutputAccum, 0, 2 * MAX_FRAME_LENGTH * sizeof(float));
memset(gAnaFreq, 0, MAX_FRAME_LENGTH * sizeof(float));
memset(gAnaMagn, 0, MAX_FRAME_LENGTH * sizeof(float));
memset(gFFTworksp, 0, 2 * MAX_FRAME_LENGTH * sizeof(double));
memset(gLastPhase, 0, (MAX_FRAME_LENGTH / 2 + 1) * sizeof(double));
memset(gSumPhase, 0, (MAX_FRAME_LENGTH / 2 + 1) * sizeof(double));
memset(gOutputAccum, 0, 2 * MAX_FRAME_LENGTH * sizeof(double));
memset(gAnaFreq, 0, MAX_FRAME_LENGTH * sizeof(double));
memset(gAnaMagn, 0, MAX_FRAME_LENGTH * sizeof(double));
lastPitchShift = 1.0;
}
};

Expand Down Expand Up @@ -101,9 +103,6 @@ class AudioEffectPitchShift : public AudioEffect {
float pitch_scale;
int oversampling;
FFTSize fft_size;
float wet;
float dry;
bool filter;

protected:
static void _bind_methods();
Expand Down

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