ref: e5da2ec9cb795c6247a454b4605adc38f167b9dd
dir: /src/polyphas.c/
/*
* July 14, 1998
* Copyright 1998 K. Bradley, Carnegie Mellon University
*
* This 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 of the License, or (at your option) any later version.
*
* This library 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 this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
*/
/*
* October 29, 1999
* Various changes, bugfixes, speedups, by Stan Brooks.
*
*/
/*
* Sound Tools rate change effect file.
*/
#include <math.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "st_i.h"
#define Float float/*double*/
#define ISCALE 0x10000
#define MF 30
typedef struct {
int up,down; /* up/down conversion factors for this stage */
int filt_len; /* # coefficients in filter_array */
Float *filt_array; /* filter coefficients */
int held; /* # samples held in input but not yet processed */
int hsize; /* # samples of past-history kept in lower window */
int size; /* # samples current data which window can accept */
Float *window; /* this is past_hist[hsize], then input[size] */
} polystage;
typedef struct polyphase {
st_rate_t lcmrate; /* least common multiple of rates */
st_rate_t inskip, outskip; /* LCM increments for I & O rates */
double Factor; /* out_rate/in_rate */
unsigned long total; /* number of filter stages */
st_size_t oskip; /* output samples to skip at start*/
double inpipe; /* output samples 'in the pipe' */
polystage *stage[MF]; /* array of pointers to polystage structs */
} *poly_t;
/*
* Process options
*/
/* Options:
-w <nut / ham> : window type
-width <short / long> : window width
short = 128 samples
long = 1024 samples
<num> num: explicit number
-cutoff <float> : frequency cutoff for base bandwidth.
Default = 0.95 = 95%
*/
static int win_type = 0;
static int win_width = 1024;
static Float cutoff = 0.95;
int st_poly_getopts(eff_t effp, int n, char **argv)
{
/* 0: nuttall
1: hamming */
win_type = 0;
/* width: short = 128
long = 1024 (default) */
win_width = 1024;
/* cutoff: frequency cutoff of base bandwidth in percentage. */
cutoff = 0.95;
while(n >= 2) {
/* Window type check */
if(!strcmp(argv[0], "-w")) {
if(!strcmp(argv[1], "ham"))
win_type = 1;
if(!strcmp(argv[1], "nut"))
win_type = 0;
argv += 2;
n -= 2;
continue;
}
/* Window width check */
if(!strcmp(argv[0], "-width")) {
if(!strcmp(argv[1], "short"))
win_width = 128;
else if(!strcmp(argv[1], "long"))
win_width = 1024;
else
win_width = atoi(argv[1]);
argv += 2;
n -= 2;
continue;
}
/* Cutoff frequency check */
if(!strcmp(argv[0], "-cutoff")) {
cutoff = atof(argv[1]);
argv += 2;
n -= 2;
continue;
}
st_fail("Polyphase: unknown argument (%s %s)!", argv[0], argv[1]);
return (ST_EOF);
}
return (ST_SUCCESS);
}
/*
* Prepare processing.
*/
static const unsigned short primes[] = {
2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37,
41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89,
97, 101, 103, 107, 109, 113, 127, 131, 137, 139, 149, 151,
157, 163, 167, 173, 179, 181, 191, 193, 197, 199, 211, 223,
227, 229, 233, 239, 241, 251, 257, 263, 269, 271, 277, 281,
283, 293, 307, 311, 313, 317, 331, 337, 347, 349, 353, 359,
367, 373, 379, 383, 389, 397, 401, 409, 419, 421, 431, 433,
439, 443, 449, 457, 461, 463, 467, 479, 487, 491, 499, 503,
509, 521, 523, 541, 547, 557, 563, 569, 571, 577, 587, 593,
599, 601, 607, 613, 617, 619, 631, 641, 643, 647, 653, 659,
661, 673, 677, 683, 691, 701, 709, 719, 727, 733, 739, 743,
751, 757, 761, 769, 773, 787, 797, 809, 811, 821, 823, 827,
829, 839, 853, 857, 859, 863, 877, 881, 883, 887, 907, 911,
919, 929, 937, 941, 947, 953, 967, 971, 977, 983, 991, 997,
0
};
#ifndef max
#define max(x,y) ((x > y) ? x : y)
#endif
#ifndef min
#define min(x,y) ((x < y) ? x : y)
#endif
static int prime(int n, int *q0)
{
const unsigned short *p;
int pr, *q;
p = primes;
q = q0;
st_report("factors(%d) =",n);
while (n > 1) {
while ((pr = *p) && (n % pr)) p++;
if (!pr) {
st_fail("Number %d too large of a prime.\n",n);
pr = n;
}
*q++ = pr;
n /= pr;
}
*q = 0;
for (pr=0; pr<q-q0; pr++) st_report(" %d",q0[pr]);
st_report("\n");
return (q-q0);
}
static int permute(int *m, int *l, int ct, int ct1, int amalg)
{
int k, n;
int *p;
int *q;
p=l; q=m;
while (ct1>ct) { *q++=1; ct++;}
while ((*q++=*p++)) ;
if (ct<=1) return ct;
for (k=ct; k>1; ) {
int tmp;
unsigned long j;
j = (rand()%32768L) + ((rand()%32768L)<<13); /* reasonably big */
j = j % k; /* non-negative! */
k--;
if (j != k) {
tmp = m[k]; m[k]=m[j]; m[j]=tmp;
}
}
/* now m is a 'random' permutation of l */
p = q = m;
n = *q++;
while ((k=*q++)) {
if ((n * k <= amalg) && (rand() & 1)) {
n *= k;
} else {
*p++ = n;
n = k;
}
}
if (n) *p++=n;
*p = 0;
/*for (k=0; k<p-m; k++) st_report(" %d",m[k]);*/
/*st_report("\n");*/
return (p-m);
}
static int optimize_factors(int numer, int denom, int *l1, int *l2)
{
int f_min,c_min,u_min,ct1,ct2;
int amalg;
int k;
static int m1[MF],m2[MF];
static int b1[MF],b2[MF];
memset(m1,0,sizeof(int)*MF);
memset(m2,0,sizeof(int)*MF);
memset(b1,0,sizeof(int)*MF);
memset(b2,0,sizeof(int)*MF);
f_min = numer; if (f_min>denom) f_min = denom;
c_min = 1<<30;
u_min = 0;
/* Find the prime factors of numer and denom */
ct1 = prime(numer,l1);
ct2 = prime(denom,l2);
for (amalg = max(9,l2[0]); amalg<= 9+l2[ct2-1]; amalg++) {
for (k = 0; k<100000; k++) {
int u,u1,u2,j,f,cost;
cost = 0;
f = denom;
u = min(ct1,ct2) + 1;
/*st_report("pfacts(%d): ", numer);*/
u1 = permute(m1,l1,ct1,u,amalg);
/*st_report("pfacts(%d): ", denom);*/
u2 = permute(m2,l2,ct2,u,amalg);
u = max(u1,u2);
for (j=0; j<u; j++) {
if (j>=u1) m1[j]=1;
if (j>=u2) m2[j]=1;
f = (f * m1[j])/m2[j];
if (f < f_min) goto fail;
cost += f + m1[j]*m2[j];
}
if (c_min>cost) {
c_min = cost;
u_min = u;
# if 0
st_report("c_min %d, [%d-%d]:",c_min,numer,denom);
for (j=0; j<u; j++)
st_report(" (%d,%d)",m1[j],m2[j]);
st_report("\n");
# endif
memcpy(b1,m1,u*sizeof(int));
memcpy(b2,m2,u*sizeof(int));
}
fail:
;;
}
if (u_min) break;
}
if (u_min) {
memcpy(l1,b1,u_min*sizeof(int));
memcpy(l2,b2,u_min*sizeof(int));
}
l1[u_min] = 0;
l2[u_min] = 0;
return u_min;
}
#ifndef PI
#define PI 3.14159265358979
#endif
/* Calculate a Nuttall window of a given length.
Buffer must already be allocated to appropriate size.
*/
static void nuttall(Float *buffer, int length)
{
int j;
double N;
int N1;
if(buffer == NULL || length <= 0)
st_fail("Illegal buffer %p or length %d to nuttall.\n", buffer, length);
/* Initial variable setups. */
N = length;
N1 = length/2;
for(j = 0; j < length; j++) {
buffer[j] = 0.36335819 +
0.4891775 * cos(2*PI*1*(j - N1) / N) +
0.1365995 * cos(2*PI*2*(j - N1) / N) +
0.0106411 * cos(2*PI*3*(j - N1) / N);
}
}
/* Calculate a Hamming window of given length.
Buffer must already be allocated to appropriate size.
*/
static void hamming(Float *buffer, int length)
{
int j;
int N1;
if(buffer == NULL || length <= 0)
st_fail("Illegal buffer %p or length %d to hamming.\n",buffer,length);
N1 = length/2;
for(j=0;j<length;j++)
buffer[j] = 0.5 - 0.46 * cos(PI*j/N1);
}
/* Calculate the sinc function properly */
static Float sinc(Float value)
{
return(fabs(value) < 1E-50 ? 1.0 : sin(value) / value);
}
/* Design a low-pass FIR filter using window technique.
Length of filter is in length, cutoff frequency in cutoff.
0 < cutoff <= 1.0 (normalized frequency)
buffer must already be allocated.
*/
static void fir_design(Float *buffer, int length, Float cutoff)
{
int j;
double sum;
if(buffer == NULL || length < 0 || cutoff < 0 || cutoff > PI)
st_fail("Illegal buffer %p, length %d, or cutoff %f.\n",buffer,length,cutoff);
/* Use the user-option of window type */
if(win_type == 0)
nuttall(buffer, length); /* Design Nuttall window: ** dB cutoff */
else
hamming(buffer,length); /* Design Hamming window: 43 dB cutoff */
/* st_report("# fir_design length=%d, cutoff=%8.4f\n",length,cutoff); */
/* Design filter: windowed sinc function */
sum = 0.0;
for(j=0;j<length;j++) {
buffer[j] *= sinc(PI*cutoff*(j-length/2)); /* center at length/2 */
/* st_report("%.1f %.6f\n",(float)j,buffer[j]); */
sum += buffer[j];
}
sum = (double)1.0/sum;
/* Normalize buffer to have gain of 1.0: prevent roundoff error */
for(j=0;j<length;j++) {
buffer[j] *= sum;
}
/* st_report("# end\n\n"); */
}
#define RIBLEN 2048
int st_poly_start(eff_t effp)
{
poly_t rate = (poly_t) effp->priv;
static int l1[MF], l2[MF];
double skip = 0;
int total, size, uprate;
int k;
if (effp->ininfo.rate == effp->outinfo.rate)
{
st_fail("Input and Output rate must not be the same to use polyphase effect");
return(ST_EOF);
}
st_initrand();
rate->lcmrate = st_lcm((st_sample_t)effp->ininfo.rate,
(st_sample_t)effp->outinfo.rate);
/* Cursory check for LCM overflow.
* If both rate are below 65k, there should be no problem.
* 16 bits x 16 bits = 32 bits, which we can handle.
*/
rate->inskip = rate->lcmrate / effp->ininfo.rate;
rate->outskip = rate->lcmrate / effp->outinfo.rate;
rate->Factor = (double)rate->inskip / (double)rate->outskip;
rate->inpipe = 0;
{
int f = RIBLEN/max(rate->inskip,rate->outskip);
if (f == 0) f = 1;
size = f * rate->outskip; /* reasonable input block size */
}
/* Find the prime factors of inskip and outskip */
total = optimize_factors(rate->inskip, rate->outskip, l1, l2);
rate->total = total;
/* l1 and l2 are now lists of the up/down factors for conversion */
st_report("Poly: input rate %d, output rate %d. %d stages.",
effp->ininfo.rate, effp->outinfo.rate,total);
st_report("Poly: window: %s size: %d cutoff: %f.",
(win_type == 0) ? ("nut") : ("ham"), win_width, cutoff);
/* Create an array of filters and past history */
uprate = effp->ininfo.rate;
for (k = 0; k < total; k++) {
int j, prod, f_cutoff, f_len;
polystage *s;
rate->stage[k] = s = (polystage*) malloc(sizeof(polystage));
s->up = l1[k];
s->down = l2[k];
f_cutoff = max(s->up, s->down);
f_len = max(20 * f_cutoff, win_width);
prod = s->up * s->down;
if (prod > 2*f_len) prod = s->up;
f_len = ((f_len+prod-1)/prod) * prod; /* reduces rounding-errors in polyphase() */
s->size = size;
s->hsize = f_len/s->up; /* this much of window is past-history */
s->held = 0;
st_report("Poly: stage %d: Up by %d, down by %d, i_samps %d, hsize %d",
k+1,s->up,s->down,size, s->hsize);
s->filt_len = f_len;
s->filt_array = (Float *) malloc(sizeof(Float) * f_len);
s->window = (Float *) malloc(sizeof(Float) * (s->hsize+size));
/* zero past_history section of window */
for(j = 0; j < s->hsize; j++)
s->window[j] = 0.0;
uprate *= s->up;
st_report("Poly: : filt_len %d, cutoff freq %.1f",
f_len, uprate*cutoff/f_cutoff);
uprate /= s->down;
fir_design(s->filt_array, f_len, cutoff/f_cutoff);
/* s->filt_array[f_len-1]=0; */
skip *= s->up;
skip += f_len;
skip /= s->down;
size = (size * s->up) / s->down; /* this is integer */
}
rate->oskip = skip/2;
{ /* bogus last stage is for output buffering */
polystage *s;
rate->stage[k] = s = (polystage*) malloc(sizeof(polystage));
s->up = s->down = 0;
s->size = size;
s->hsize = 0;
s->held = 0;
s->filt_len = 0;
s->filt_array = NULL;
s->window = (Float *) malloc(sizeof(Float) * size);
}
st_report("Poly: output samples %d, oskip %d",size, rate->oskip);
return (ST_SUCCESS);
}
/*
* Processed signed long samples from ibuf to obuf.
* Return number of samples processed.
*/
/* REMARK: putting this in a separate subroutine improves gcc's optimization */
static double st_prod(const Float *q, int qstep, const Float *p, int n)
{
double sum = 0;
const Float *p0;
p0 = p-n;
while (p>p0) {
sum += *p * *q;
q += qstep;
p -= 1;
}
return sum;
}
static void polyphase(Float *output, polystage *s)
{
int mm;
int up = s->up;
int down = s->down;
int f_len = s->filt_len;
const Float *in;
Float *o; /* output pointer */
Float *o_top;
in = s->window + s->hsize;
/*for (mm=0; mm<s->filt_len; mm++) st_report("cf_%d %f\n",mm,s->filt_array[mm]);*/
/* assumes s->size divisible by down (now true) */
o_top = output + (s->size * up) / down;
/*st_report(" isize %d, osize %d, up %d, down %d, N %d", s->size, o_top-output, up, down, f_len);*/
for (mm=0, o=output; o < o_top; mm+=down, o++) {
double sum;
const Float *p, *q;
q = s->filt_array + (mm%up); /* decimated coef pointer */
p = in + (mm/up);
sum = st_prod(q, up, p, f_len/up);
*o = sum * up;
}
}
static void update_hist(Float *hist, int hist_size, int in_size)
{
Float *p, *p1, *q;
p = hist;
p1 = hist+hist_size;
q = hist+in_size;
while (p<p1)
*p++ = *q++;
}
static st_sample_t clipfloat(Float sample)
{
if (sample > ST_SAMPLE_MAX)
return ST_SAMPLE_MAX;
if (sample < -ST_SAMPLE_MAX)
return -ST_SAMPLE_MAX;
return sample;
}
int st_poly_flow(eff_t effp, st_sample_t *ibuf, st_sample_t *obuf,
st_size_t *isamp, st_size_t *osamp)
{
poly_t rate = (poly_t) effp->priv;
polystage *s0,*s1;
/* Sanity check: how much can we tolerate? */
/* st_report("*isamp=%d *osamp=%d\n",*isamp,*osamp); fflush(stderr); */
s0 = rate->stage[0]; /* the first stage */
s1 = rate->stage[rate->total]; /* the 'last' stage is output buffer */
{
int in_size, gap, k;
in_size = *isamp;
gap = s0->size - s0->held; /* space available in this 'input' buffer */
if ((in_size > gap) || (ibuf==NULL)) {
*isamp = in_size = gap;
}
if (in_size > 0) {
Float *q;
q = s0->window + s0->hsize;
if (s0!=s1) q += s0->held; /* the last (output) buffer doesn't shift history */
if (ibuf != NULL) {
rate->inpipe += rate->Factor * in_size;
for (k=0; k<in_size; k++)
*q++ = (Float)ibuf[k] / ISCALE;
} else { /* ibuf==NULL is draining */
for(k=0;k<in_size;k++)
*q++ = 0.0;
}
s0->held += in_size;
}
}
if (s0->held == s0->size && s1->held == 0) {
int k;
/* input buffer full, output buffer empty, so do process */
for(k=0; k<rate->total; k++) {
polystage *s;
Float *out;
s = rate->stage[k];
out = rate->stage[k+1]->window + rate->stage[k+1]->hsize;
/* st_report("k=%d insize=%d\n",k,in_size); fflush(stderr); */
polyphase(out, s);
/* copy input history into lower portion of rate->window[k] */
update_hist(s->window, s->hsize, s->size);
s->held = 0;
}
s1->held = s1->size;
s1->hsize = 0;
}
{
st_sample_t *q;
st_size_t out_size;
st_size_t oskip;
Float *out_buf;
int k;
oskip = rate->oskip;
out_size = s1->held;
out_buf = s1->window + s1->hsize;
if(ibuf == NULL && out_size > ceil(rate->inpipe)) {
out_size = ceil(rate->inpipe);
}
if (out_size > oskip + *osamp) out_size = oskip + *osamp;
for(q=obuf, k=oskip; k < out_size; k++)
*q++ = clipfloat(out_buf[k] * ISCALE); /* should clip-limit */
*osamp = q-obuf;
rate->inpipe -= *osamp;
oskip -= out_size - *osamp;
rate->oskip = oskip;
s1->hsize += out_size;
s1->held -= out_size;
if (s1->held == 0) {
s1->hsize = 0;
}
}
return (ST_SUCCESS);
}
/*
* Process tail of input samples.
*/
int st_poly_drain(eff_t effp, st_sample_t *obuf, st_size_t *osamp)
{
st_size_t in_size;
/* Call "flow" with NULL input. */
st_poly_flow(effp, NULL, obuf, &in_size, osamp);
return (ST_SUCCESS);
}
/*
* Do anything required when you stop reading samples.
* Don't close input file!
*/
int st_poly_stop(eff_t effp)
{
poly_t rate = (poly_t) effp->priv;
polystage *s;
int k;
for(k = 0; k <= rate->total; k++) {
s = rate->stage[k];
free((void *) s->window);
if (s->filt_array) free((void *) s->filt_array);
free((void *) s);
}
return (ST_SUCCESS);
}