/* * (c) 2002 Fabrice Bellard * * This file is part of FFmpeg. * * FFmpeg 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. * * FFmpeg 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 FFmpeg; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ /** * @file fft-test.c * FFT and MDCT tests. */ #include "dsputil.h" #include <math.h> #include <unistd.h> #include <sys/time.h> #include <stdlib.h> #include <string.h> #undef exit #undef random /* reference fft */ #define MUL16(a,b) ((a) * (b)) #define CMAC(pre, pim, are, aim, bre, bim) \ {\ pre += (MUL16(are, bre) - MUL16(aim, bim));\ pim += (MUL16(are, bim) + MUL16(bre, aim));\ } FFTComplex *exptab; void fft_ref_init(int nbits, int inverse) { int n, i; double c1, s1, alpha; n = 1 << nbits; exptab = av_malloc((n / 2) * sizeof(FFTComplex)); for(i=0;i<(n/2);i++) { alpha = 2 * M_PI * (float)i / (float)n; c1 = cos(alpha); s1 = sin(alpha); if (!inverse) s1 = -s1; exptab[i].re = c1; exptab[i].im = s1; } } void fft_ref(FFTComplex *tabr, FFTComplex *tab, int nbits) { int n, i, j, k, n2; double tmp_re, tmp_im, s, c; FFTComplex *q; n = 1 << nbits; n2 = n >> 1; for(i=0;i<n;i++) { tmp_re = 0; tmp_im = 0; q = tab; for(j=0;j<n;j++) { k = (i * j) & (n - 1); if (k >= n2) { c = -exptab[k - n2].re; s = -exptab[k - n2].im; } else { c = exptab[k].re; s = exptab[k].im; } CMAC(tmp_re, tmp_im, c, s, q->re, q->im); q++; } tabr[i].re = tmp_re; tabr[i].im = tmp_im; } } void imdct_ref(float *out, float *in, int nbits) { int n = 1<<nbits; int k, i, a; double sum, f; for(i=0;i<n;i++) { sum = 0; for(k=0;k<n/2;k++) { a = (2 * i + 1 + (n / 2)) * (2 * k + 1); f = cos(M_PI * a / (double)(2 * n)); sum += f * in[k]; } out[i] = -sum; } } /* NOTE: no normalisation by 1 / N is done */ void mdct_ref(float *output, float *input, int nbits) { int n = 1<<nbits; int k, i; double a, s; /* do it by hand */ for(k=0;k<n/2;k++) { s = 0; for(i=0;i<n;i++) { a = (2*M_PI*(2*i+1+n/2)*(2*k+1) / (4 * n)); s += input[i] * cos(a); } output[k] = s; } } float frandom(void) { return (float)((random() & 0xffff) - 32768) / 32768.0; } int64_t gettime(void) { struct timeval tv; gettimeofday(&tv,NULL); return (int64_t)tv.tv_sec * 1000000 + tv.tv_usec; } void check_diff(float *tab1, float *tab2, int n) { int i; double max= 0; double error= 0; for(i=0;i<n;i++) { double e= fabsf(tab1[i] - tab2[i]); if (e >= 1e-3) { av_log(NULL, AV_LOG_ERROR, "ERROR %d: %f %f\n", i, tab1[i], tab2[i]); } error+= e*e; if(e>max) max= e; } av_log(NULL, AV_LOG_INFO, "max:%f e:%g\n", max, sqrt(error)/n); } void help(void) { av_log(NULL, AV_LOG_INFO,"usage: fft-test [-h] [-s] [-i] [-n b]\n" "-h print this help\n" "-s speed test\n" "-m (I)MDCT test\n" "-i inverse transform test\n" "-n b set the transform size to 2^b\n" ); exit(1); } int main(int argc, char **argv) { FFTComplex *tab, *tab1, *tab_ref; FFTSample *tab2; int it, i, c; int do_speed = 0; int do_mdct = 0; int do_inverse = 0; FFTContext s1, *s = &s1; MDCTContext m1, *m = &m1; int fft_nbits, fft_size; fft_nbits = 9; for(;;) { c = getopt(argc, argv, "hsimn:"); if (c == -1) break; switch(c) { case 'h': help(); break; case 's': do_speed = 1; break; case 'i': do_inverse = 1; break; case 'm': do_mdct = 1; break; case 'n': fft_nbits = atoi(optarg); break; } } fft_size = 1 << fft_nbits; tab = av_malloc(fft_size * sizeof(FFTComplex)); tab1 = av_malloc(fft_size * sizeof(FFTComplex)); tab_ref = av_malloc(fft_size * sizeof(FFTComplex)); tab2 = av_malloc(fft_size * sizeof(FFTSample)); if (do_mdct) { if (do_inverse) av_log(NULL, AV_LOG_INFO,"IMDCT"); else av_log(NULL, AV_LOG_INFO,"MDCT"); ff_mdct_init(m, fft_nbits, do_inverse); } else { if (do_inverse) av_log(NULL, AV_LOG_INFO,"IFFT"); else av_log(NULL, AV_LOG_INFO,"FFT"); ff_fft_init(s, fft_nbits, do_inverse); fft_ref_init(fft_nbits, do_inverse); } av_log(NULL, AV_LOG_INFO," %d test\n", fft_size); /* generate random data */ for(i=0;i<fft_size;i++) { tab1[i].re = frandom(); tab1[i].im = frandom(); } /* checking result */ av_log(NULL, AV_LOG_INFO,"Checking...\n"); if (do_mdct) { if (do_inverse) { imdct_ref((float *)tab_ref, (float *)tab1, fft_nbits); ff_imdct_calc(m, tab2, (float *)tab1); check_diff((float *)tab_ref, tab2, fft_size); } else { mdct_ref((float *)tab_ref, (float *)tab1, fft_nbits); ff_mdct_calc(m, tab2, (float *)tab1); check_diff((float *)tab_ref, tab2, fft_size / 2); } } else { memcpy(tab, tab1, fft_size * sizeof(FFTComplex)); ff_fft_permute(s, tab); ff_fft_calc(s, tab); fft_ref(tab_ref, tab1, fft_nbits); check_diff((float *)tab_ref, (float *)tab, fft_size * 2); } /* do a speed test */ if (do_speed) { int64_t time_start, duration; int nb_its; av_log(NULL, AV_LOG_INFO,"Speed test...\n"); /* we measure during about 1 seconds */ nb_its = 1; for(;;) { time_start = gettime(); for(it=0;it<nb_its;it++) { if (do_mdct) { if (do_inverse) { ff_imdct_calc(m, (float *)tab, (float *)tab1); } else { ff_mdct_calc(m, (float *)tab, (float *)tab1); } } else { memcpy(tab, tab1, fft_size * sizeof(FFTComplex)); ff_fft_calc(s, tab); } } duration = gettime() - time_start; if (duration >= 1000000) break; nb_its *= 2; } av_log(NULL, AV_LOG_INFO,"time: %0.1f us/transform [total time=%0.2f s its=%d]\n", (double)duration / nb_its, (double)duration / 1000000.0, nb_its); } if (do_mdct) { ff_mdct_end(m); } else { ff_fft_end(s); } return 0; }