static void FFT(unsigned NumSamples,
int InverseTransform,
const float *RealIn, float *ImagIn, float *RealOut, float *ImagOut)
{
unsigned i;
double * work = malloc(2 * NumSamples * sizeof(*work));
for (i = 0; i < 2 * NumSamples; i += 2) {
work[i] = RealIn[i >> 1];
work[i + 1] = ImagIn? ImagIn[i >> 1] : 0;
}
lsx_safe_cdft(2 * (int)NumSamples, InverseTransform? -1 : 1, work);
if (InverseTransform) for (i = 0; i < 2 * NumSamples; i += 2) {
RealOut[i >> 1] = work[i] / NumSamples;
ImagOut[i >> 1] = work[i + 1] / NumSamples;
}
else for (i = 0; i < 2 * NumSamples; i += 2) {
static int flow(sox_effect_t * effp, const sox_sample_t * ibuf,
sox_sample_t * obuf, size_t * isamp, size_t * osamp)
{
priv_t *p = (priv_t *) effp->priv;
size_t i, len = *isamp = *osamp = min(*isamp, *osamp);
double magn, phase, tmp, window, real, imag;
double freqPerBin, expct;
long k, qpd, index, inFifoLatency, stepSize, fftFrameSize2;
float pitchShift = p->shift;
/* set up some handy variables */
fftFrameSize2 = p->fftFrameSize / 2;
stepSize = p->fftFrameSize / p->ovsamp;
freqPerBin = effp->in_signal.rate / p->fftFrameSize;
expct = 2. * M_PI * (double) stepSize / (double) p->fftFrameSize;
inFifoLatency = p->fftFrameSize - stepSize;
if (!p->gRover)
p->gRover = inFifoLatency;
/* main processing loop */
for (i = 0; i < len; i++) {
SOX_SAMPLE_LOCALS;
++p->in_pos;
/* As long as we have not yet collected enough data just read in */
p->gInFIFO[p->gRover] = SOX_SAMPLE_TO_FLOAT_32BIT(ibuf[i], effp->clips);
obuf[i] = SOX_FLOAT_32BIT_TO_SAMPLE(
p->gOutFIFO[p->gRover - inFifoLatency], effp->clips);
p->gRover++;
/* now we have enough data for processing */
if (p->gRover >= p->fftFrameSize) {
if (p->bends_pos != p->nbends && p->in_pos >=
p->bends[p->bends_pos].start + p->bends[p->bends_pos].duration) {
pitchShift = p->shift *= pow(2., p->bends[p->bends_pos].cents / 1200);
++p->bends_pos;
}
if (p->bends_pos != p->nbends && p->in_pos >= p->bends[p->bends_pos].start) {
double progress = (double)(p->in_pos - p->bends[p->bends_pos].start) /
p->bends[p->bends_pos].duration;
progress = 1 - cos(M_PI * progress);
progress *= p->bends[p->bends_pos].cents * (.5 / 1200);
pitchShift = p->shift * pow(2., progress);
}
p->gRover = inFifoLatency;
/* do windowing and re,im interleave */
for (k = 0; k < p->fftFrameSize; k++) {
window = -.5 * cos(2 * M_PI * k / (double) p->fftFrameSize) + .5;
p->gFFTworksp[2 * k] = p->gInFIFO[k] * window;
p->gFFTworksp[2 * k + 1] = 0.;
}
/* ***************** ANALYSIS ******************* */
lsx_safe_cdft(2 * p->fftFrameSize, 1, p->gFFTworksp);
/* this is the analysis step */
for (k = 0; k <= fftFrameSize2; k++) {
/* de-interlace FFT buffer */
real = p->gFFTworksp[2 * k];
imag = - p->gFFTworksp[2 * k + 1];
/* compute magnitude and phase */
magn = 2. * sqrt(real * real + imag * imag);
phase = atan2(imag, real);
/* compute phase difference */
tmp = phase - p->gLastPhase[k];
p->gLastPhase[k] = phase;
tmp -= (double) k *expct; /* subtract expected phase difference */
/* map delta phase into +/- Pi interval */
qpd = tmp / M_PI;
if (qpd >= 0)
qpd += qpd & 1;
else qpd -= qpd & 1;
tmp -= M_PI * (double) qpd;
/* get deviation from bin frequency from the +/- Pi interval */
tmp = p->ovsamp * tmp / (2. * M_PI);
/* compute the k-th partials' true frequency */
tmp = (double) k *freqPerBin + tmp * freqPerBin;
/* store magnitude and true frequency in analysis arrays */
p->gAnaMagn[k] = magn;
p->gAnaFreq[k] = tmp;
}
/* this does the actual pitch shifting */
memset(p->gSynMagn, 0, p->fftFrameSize * sizeof(float));
memset(p->gSynFreq, 0, p->fftFrameSize * sizeof(float));
for (k = 0; k <= fftFrameSize2; k++) {
index = k * pitchShift;
if (index <= fftFrameSize2) {
p->gSynMagn[index] += p->gAnaMagn[k];
p->gSynFreq[index] = p->gAnaFreq[k] * pitchShift;
}
}
for (k = 0; k <= fftFrameSize2; k++) { /* SYNTHESIS */
/* get magnitude and true frequency from synthesis arrays */
magn = p->gSynMagn[k], tmp = p->gSynFreq[k];
tmp -= (double) k *freqPerBin; /* subtract bin mid frequency */
tmp /= freqPerBin; /* get bin deviation from freq deviation */
tmp = 2. * M_PI * tmp / p->ovsamp; /* take p->ovsamp into account */
tmp += (double) k *expct; /* add the overlap phase advance back in */
p->gSumPhase[k] += tmp; /* accumulate delta phase to get bin phase */
phase = p->gSumPhase[k];
/* get real and imag part and re-interleave */
p->gFFTworksp[2 * k] = magn * cos(phase);
p->gFFTworksp[2 * k + 1] = - magn * sin(phase);
}
for (k = p->fftFrameSize + 2; k < 2 * p->fftFrameSize; k++)
p->gFFTworksp[k] = 0.; /* zero negative frequencies */
lsx_safe_cdft(2 * p->fftFrameSize, -1, p->gFFTworksp);
/* do windowing and add to output accumulator */
for (k = 0; k < p->fftFrameSize; k++) {
window =
-.5 * cos(2. * M_PI * (double) k / (double) p->fftFrameSize) + .5;
p->gOutputAccum[k] +=
2. * window * p->gFFTworksp[2 * k] / (fftFrameSize2 * p->ovsamp);
}
for (k = 0; k < stepSize; k++)
p->gOutFIFO[k] = p->gOutputAccum[k];
memmove(p->gOutputAccum, /* shift accumulator */
p->gOutputAccum + stepSize, p->fftFrameSize * sizeof(float));
for (k = 0; k < inFifoLatency; k++) /* move input FIFO */
p->gInFIFO[k] = p->gInFIFO[k + stepSize];
}
}
return SOX_SUCCESS;
}
