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/*
paulstretch.c:
This is an implementation of the paulstretch algorithm by
Paul Nasca Octavian, based off of the Numpy/Scipy python
implementation written by the same author.
Copyright (C) 2016 by Paul Batchelor
This file is part of Csound.
The Csound Library is free software; you can redistribute it
and/or modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
Csound is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with Csound; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
02110-1301 USA
*/
#include <stdlib.h>
#include <complex.h>
#ifdef _MSC_VER
#define _USE_MATH_DEFINES
#endif
#include <math.h>
#include <math.h>
#include "csoundCore.h"
#include "interlocks.h"
#include "H/fftlib.h"
#ifdef ANDROID
float crealf(_Complex float);
float cimagf(_Complex float);
#endif
typedef struct {
OPDS h;
MYFLT *out, *stretch, *winsize, *ifn;
MYFLT start_pos, displace_pos;
MYFLT *window;
MYFLT *old_windowed_buf;
MYFLT *hinv_buf;
MYFLT *output;
FUNC *ft;
uint32_t windowsize;
uint32_t half_windowsize;
MYFLT *tmp;
uint32_t counter;
AUXCH m_window;
AUXCH m_old_windowed_buf;
AUXCH m_hinv_buf;
AUXCH m_output;
AUXCH m_tmp;
} PAULSTRETCH;
static void compute_block(CSOUND *csound, PAULSTRETCH *p)
{
uint32_t istart_pos = floor(p->start_pos);
uint32_t pos;
uint32_t i;
uint32_t windowsize = p->windowsize;
uint32_t half_windowsize = p->half_windowsize;
MYFLT *hinv_buf = p->hinv_buf;
MYFLT *old_windowed_buf= p->old_windowed_buf;
MYFLT *tbl = p->ft->ftable;
MYFLT *window = p->window;
MYFLT *output= p->output;
MYFLT *tmp = p->tmp;
for (i = 0; i < windowsize; i++) {
pos = istart_pos + i;
if (LIKELY(pos < p->ft->flen)) {
tmp[i] = tbl[pos] * window[i];
} else {
tmp[i] = FL(0.0);
}
}
/* re-order bins and take FFT */
tmp[p->windowsize] = tmp[1];
tmp[p->windowsize + 1] = FL(0.0);
csoundRealFFTnp2(csound, tmp, p->windowsize);
/* randomize phase */
for (i = 0; i < windowsize + 2; i += 2) {
MYFLT mag = HYPOT(tmp[i], tmp[i + 1]);
// Android 5.1 does not seem to have cexpf ...
// complex ph = cexpf(I * ((MYFLT)rand() / RAND_MAX) * 2 * PI);
// so ...
MYFLT x = (((MYFLT)rand() / RAND_MAX) * 2 * PI);
#ifdef MSVC
// TODO - Double check this is equivalent to non-windows complex definition
_Fcomplex ph = { cos(x), sin(x) };
#else
complex double ph = cos(x) + I*sin(x);
#endif
tmp[i] = mag * (MYFLT)crealf(ph);
tmp[i + 1] = mag * (MYFLT)cimagf(ph);
}
/* re-order bins and take inverse FFT */
tmp[1] = tmp[p->windowsize];
csoundInverseRealFFTnp2(csound, tmp, p->windowsize);
/* apply window and overlap */
for (i = 0; i < windowsize; i++) {
tmp[i] *= window[i];
if (i < half_windowsize) {
output[i] = (MYFLT)(tmp[i] + old_windowed_buf[half_windowsize + i]);
output[i] *= hinv_buf[i];
}
old_windowed_buf[i] = tmp[i];
}
p->start_pos += p->displace_pos;
}
static int32_t ps_init(CSOUND* csound, PAULSTRETCH *p)
{
FUNC *ftp = csound->FTnp2Find(csound, p->ifn);
uint32_t i = 0;
uint32_t size;
if (ftp == NULL)
return csound->InitError(csound, Str("paulstretch: table not found"));
p->ft = ftp;
p->windowsize = (uint32_t)FLOOR((CS_ESR * *p->winsize));
if (p->windowsize < 16) {
p->windowsize = 16;
}
p->half_windowsize = p->windowsize / 2;
p->displace_pos = (p->windowsize * FL(0.5)) / *p->stretch;
size = sizeof(MYFLT) * p->windowsize;
csound->AuxAlloc(csound, size, &(p->m_window));
p->window = p->m_window.auxp;
csound->AuxAlloc(csound, size, &p->m_old_windowed_buf);
p->old_windowed_buf = p->m_old_windowed_buf.auxp;
csound->AuxAlloc(csound,
(size_t)(sizeof(MYFLT) * p->half_windowsize), &p->m_hinv_buf);
p->hinv_buf = p->m_hinv_buf.auxp;
csound->AuxAlloc(csound,
(size_t)(sizeof(MYFLT) * p->half_windowsize), &p->m_output);
p->output = p->m_output.auxp;
csound->AuxAlloc(csound, size + 2 * sizeof(MYFLT), &p->m_tmp);
p->tmp = p->m_tmp.auxp;
/* Create Hann window */
for (i = 0; i < p->windowsize; i++) {
p->window[i] = FL(0.5) - COS(i * TWOPI_F / (p->windowsize - 1)) * FL(0.5);
}
/* create inverse Hann window */
{
MYFLT hinv_sqrt2 = (1 + SQRT(FL(0.5))) * FL(0.5);
for (i = 0; i < p->half_windowsize; i++) {
p->hinv_buf[i] =
hinv_sqrt2 - (FL(1.0) - hinv_sqrt2) *
COS(i * TWOPI_F / p->half_windowsize);
}
}
p->start_pos = FL(0.0);
p->counter = 0;
return OK;
}
static int32_t paulstretch_perf(CSOUND* csound, PAULSTRETCH *p)
{
uint32_t offset = p->h.insdshead->ksmps_offset;
uint32_t early = p->h.insdshead->ksmps_no_end;
uint32_t n, nsmps = CS_KSMPS;
MYFLT *out = p->out;
if (UNLIKELY(offset)) {
memset(p->out, '\0', offset*sizeof(MYFLT));
memset(p->out, '\0', offset*sizeof(MYFLT));
}
if (UNLIKELY(early)) {
nsmps -= early;
memset(&p->out[nsmps], '\0', early*sizeof(MYFLT));
}
for (n = offset; n < nsmps; n++) {
if (p->counter == 0) {
compute_block(csound, p);
}
out[n] = p->output[p->counter];
p->counter = (p->counter + 1) % p->half_windowsize;
}
return OK;
}
static OENTRY paulstretch_localops[] = {
{ "paulstretch", (int32_t) sizeof(PAULSTRETCH), TR, 3, "a", "iii",
(int32_t (*)(CSOUND *, void *)) ps_init,
(int32_t (*)(CSOUND *, void *)) paulstretch_perf}
};
LINKAGE_BUILTIN(paulstretch_localops)
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