315 lines
7.8 KiB
C
315 lines
7.8 KiB
C
/*
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* (c) 2002 Fabrice Bellard
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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/**
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* @file libavcodec/fft-test.c
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* FFT and MDCT tests.
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*/
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#include "libavutil/lfg.h"
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#include "dsputil.h"
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#include <math.h>
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#include <unistd.h>
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#include <sys/time.h>
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#include <stdlib.h>
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#include <string.h>
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#undef exit
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/* reference fft */
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#define MUL16(a,b) ((a) * (b))
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#define CMAC(pre, pim, are, aim, bre, bim) \
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{\
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pre += (MUL16(are, bre) - MUL16(aim, bim));\
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pim += (MUL16(are, bim) + MUL16(bre, aim));\
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}
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FFTComplex *exptab;
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static void fft_ref_init(int nbits, int inverse)
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{
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int n, i;
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double c1, s1, alpha;
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n = 1 << nbits;
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exptab = av_malloc((n / 2) * sizeof(FFTComplex));
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for(i=0;i<(n/2);i++) {
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alpha = 2 * M_PI * (float)i / (float)n;
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c1 = cos(alpha);
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s1 = sin(alpha);
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if (!inverse)
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s1 = -s1;
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exptab[i].re = c1;
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exptab[i].im = s1;
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}
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}
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static void fft_ref(FFTComplex *tabr, FFTComplex *tab, int nbits)
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{
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int n, i, j, k, n2;
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double tmp_re, tmp_im, s, c;
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FFTComplex *q;
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n = 1 << nbits;
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n2 = n >> 1;
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for(i=0;i<n;i++) {
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tmp_re = 0;
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tmp_im = 0;
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q = tab;
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for(j=0;j<n;j++) {
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k = (i * j) & (n - 1);
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if (k >= n2) {
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c = -exptab[k - n2].re;
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s = -exptab[k - n2].im;
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} else {
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c = exptab[k].re;
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s = exptab[k].im;
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}
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CMAC(tmp_re, tmp_im, c, s, q->re, q->im);
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q++;
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}
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tabr[i].re = tmp_re;
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tabr[i].im = tmp_im;
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}
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}
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static void imdct_ref(float *out, float *in, int nbits)
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{
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int n = 1<<nbits;
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int k, i, a;
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double sum, f;
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for(i=0;i<n;i++) {
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sum = 0;
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for(k=0;k<n/2;k++) {
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a = (2 * i + 1 + (n / 2)) * (2 * k + 1);
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f = cos(M_PI * a / (double)(2 * n));
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sum += f * in[k];
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}
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out[i] = -sum;
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}
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}
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/* NOTE: no normalisation by 1 / N is done */
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static void mdct_ref(float *output, float *input, int nbits)
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{
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int n = 1<<nbits;
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int k, i;
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double a, s;
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/* do it by hand */
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for(k=0;k<n/2;k++) {
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s = 0;
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for(i=0;i<n;i++) {
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a = (2*M_PI*(2*i+1+n/2)*(2*k+1) / (4 * n));
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s += input[i] * cos(a);
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}
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output[k] = s;
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}
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}
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static float frandom(void)
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{
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AVLFG prng;
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av_lfg_init(&prng, 1);
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return (float)((av_lfg_get(&prng) & 0xffff) - 32768) / 32768.0;
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}
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static int64_t gettime(void)
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{
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struct timeval tv;
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gettimeofday(&tv,NULL);
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return (int64_t)tv.tv_sec * 1000000 + tv.tv_usec;
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}
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static void check_diff(float *tab1, float *tab2, int n, double scale)
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{
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int i;
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double max= 0;
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double error= 0;
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for(i=0;i<n;i++) {
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double e= fabsf(tab1[i] - (tab2[i] / scale));
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if (e >= 1e-3) {
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av_log(NULL, AV_LOG_ERROR, "ERROR %d: %f %f\n",
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i, tab1[i], tab2[i]);
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}
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error+= e*e;
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if(e>max) max= e;
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}
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av_log(NULL, AV_LOG_INFO, "max:%f e:%g\n", max, sqrt(error)/n);
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}
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static void help(void)
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{
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av_log(NULL, AV_LOG_INFO,"usage: fft-test [-h] [-s] [-i] [-n b]\n"
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"-h print this help\n"
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"-s speed test\n"
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"-m (I)MDCT test\n"
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"-i inverse transform test\n"
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"-n b set the transform size to 2^b\n"
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"-f x set scale factor for output data of (I)MDCT to x\n"
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);
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exit(1);
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}
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int main(int argc, char **argv)
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{
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FFTComplex *tab, *tab1, *tab_ref;
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FFTSample *tab2;
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int it, i, c;
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int do_speed = 0;
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int do_mdct = 0;
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int do_inverse = 0;
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FFTContext s1, *s = &s1;
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MDCTContext m1, *m = &m1;
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int fft_nbits, fft_size;
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double scale = 1.0;
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fft_nbits = 9;
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for(;;) {
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c = getopt(argc, argv, "hsimn:f:");
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if (c == -1)
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break;
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switch(c) {
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case 'h':
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help();
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break;
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case 's':
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do_speed = 1;
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break;
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case 'i':
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do_inverse = 1;
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break;
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case 'm':
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do_mdct = 1;
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break;
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case 'n':
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fft_nbits = atoi(optarg);
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break;
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case 'f':
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scale = atof(optarg);
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break;
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}
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}
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fft_size = 1 << fft_nbits;
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tab = av_malloc(fft_size * sizeof(FFTComplex));
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tab1 = av_malloc(fft_size * sizeof(FFTComplex));
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tab_ref = av_malloc(fft_size * sizeof(FFTComplex));
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tab2 = av_malloc(fft_size * sizeof(FFTSample));
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if (do_mdct) {
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av_log(NULL, AV_LOG_INFO,"Scale factor is set to %f\n", scale);
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if (do_inverse)
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av_log(NULL, AV_LOG_INFO,"IMDCT");
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else
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av_log(NULL, AV_LOG_INFO,"MDCT");
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ff_mdct_init(m, fft_nbits, do_inverse, scale);
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} else {
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if (do_inverse)
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av_log(NULL, AV_LOG_INFO,"IFFT");
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else
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av_log(NULL, AV_LOG_INFO,"FFT");
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ff_fft_init(s, fft_nbits, do_inverse);
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fft_ref_init(fft_nbits, do_inverse);
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}
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av_log(NULL, AV_LOG_INFO," %d test\n", fft_size);
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/* generate random data */
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for(i=0;i<fft_size;i++) {
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tab1[i].re = frandom();
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tab1[i].im = frandom();
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}
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/* checking result */
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av_log(NULL, AV_LOG_INFO,"Checking...\n");
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if (do_mdct) {
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if (do_inverse) {
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imdct_ref((float *)tab_ref, (float *)tab1, fft_nbits);
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ff_imdct_calc(m, tab2, (float *)tab1);
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check_diff((float *)tab_ref, tab2, fft_size, scale);
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} else {
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mdct_ref((float *)tab_ref, (float *)tab1, fft_nbits);
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ff_mdct_calc(m, tab2, (float *)tab1);
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check_diff((float *)tab_ref, tab2, fft_size / 2, scale);
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}
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} else {
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memcpy(tab, tab1, fft_size * sizeof(FFTComplex));
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ff_fft_permute(s, tab);
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ff_fft_calc(s, tab);
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fft_ref(tab_ref, tab1, fft_nbits);
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check_diff((float *)tab_ref, (float *)tab, fft_size * 2, 1.0);
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}
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/* do a speed test */
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if (do_speed) {
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int64_t time_start, duration;
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int nb_its;
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av_log(NULL, AV_LOG_INFO,"Speed test...\n");
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/* we measure during about 1 seconds */
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nb_its = 1;
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for(;;) {
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time_start = gettime();
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for(it=0;it<nb_its;it++) {
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if (do_mdct) {
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if (do_inverse) {
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ff_imdct_calc(m, (float *)tab, (float *)tab1);
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} else {
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ff_mdct_calc(m, (float *)tab, (float *)tab1);
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}
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} else {
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memcpy(tab, tab1, fft_size * sizeof(FFTComplex));
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ff_fft_calc(s, tab);
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}
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}
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duration = gettime() - time_start;
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if (duration >= 1000000)
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break;
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nb_its *= 2;
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}
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av_log(NULL, AV_LOG_INFO,"time: %0.1f us/transform [total time=%0.2f s its=%d]\n",
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(double)duration / nb_its,
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(double)duration / 1000000.0,
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nb_its);
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}
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if (do_mdct) {
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ff_mdct_end(m);
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} else {
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ff_fft_end(s);
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}
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return 0;
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}
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