libavcodec/fft-test.c

   1 /*
   2  * (c) 2002 Fabrice Bellard
   3  *
   4  * This file is part of FFmpeg.
   5  *
   6  * FFmpeg is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2.1 of the License, or (at your option) any later version.
  10  *
  11  * FFmpeg is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with FFmpeg; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  19  */
  20
  21 /**
  22  * @file fft-test.c
  23  * FFT and MDCT tests.
  24  */
  25
  26 #include "dsputil.h"
  27 #include <math.h>
  28 #include <unistd.h>
  29 #include <sys/time.h>
  30 #include <stdlib.h>
  31 #include <string.h>
  32
  33 #undef exit
  34 #undef random
  35
  36 int mm_flags;
  37
  38 /* reference fft */
  39
  40 #define MUL16(a,b) ((a) * (b))
  41
  42 #define CMAC(pre, pim, are, aim, bre, bim) \
  43 {\
  44    pre += (MUL16(are, bre) - MUL16(aim, bim));\
  45    pim += (MUL16(are, bim) + MUL16(bre, aim));\
  46 }
  47
  48 FFTComplex *exptab;
  49
  50 void fft_ref_init(int nbits, int inverse)
  51 {
  52     int n, i;
  53     double c1, s1, alpha;
  54
  55     n = 1 << nbits;
  56     exptab = av_malloc((n / 2) * sizeof(FFTComplex));
  57
  58     for(i=0;i<(n/2);i++) {
  59         alpha = 2 * M_PI * (float)i / (float)n;
  60         c1 = cos(alpha);
  61         s1 = sin(alpha);
  62         if (!inverse)
  63             s1 = -s1;
  64         exptab[i].re = c1;
  65         exptab[i].im = s1;
  66     }
  67 }
  68
  69 void fft_ref(FFTComplex *tabr, FFTComplex *tab, int nbits)
  70 {
  71     int n, i, j, k, n2;
  72     double tmp_re, tmp_im, s, c;
  73     FFTComplex *q;
  74
  75     n = 1 << nbits;
  76     n2 = n >> 1;
  77     for(i=0;i<n;i++) {
  78         tmp_re = 0;
  79         tmp_im = 0;
  80         q = tab;
  81         for(j=0;j<n;j++) {
  82             k = (i * j) & (n - 1);
  83             if (k >= n2) {
  84                 c = -exptab[k - n2].re;
  85                 s = -exptab[k - n2].im;
  86             } else {
  87                 c = exptab[k].re;
  88                 s = exptab[k].im;
  89             }
  90             CMAC(tmp_re, tmp_im, c, s, q->re, q->im);
  91             q++;
  92         }
  93         tabr[i].re = tmp_re;
  94         tabr[i].im = tmp_im;
  95     }
  96 }
  97
  98 void imdct_ref(float *out, float *in, int nbits)
  99 {
 100     int n = 1<<nbits;
 101     int k, i, a;
 102     double sum, f;
 103
 104     for(i=0;i<n;i++) {
 105         sum = 0;
 106         for(k=0;k<n/2;k++) {
 107             a = (2 * i + 1 + (n / 2)) * (2 * k + 1);
 108             f = cos(M_PI * a / (double)(2 * n));
 109             sum += f * in[k];
 110         }
 111         out[i] = -sum;
 112     }
 113 }
 114
 115 /* NOTE: no normalisation by 1 / N is done */
 116 void mdct_ref(float *output, float *input, int nbits)
 117 {
 118     int n = 1<<nbits;
 119     int k, i;
 120     double a, s;
 121
 122     /* do it by hand */
 123     for(k=0;k<n/2;k++) {
 124         s = 0;
 125         for(i=0;i<n;i++) {
 126             a = (2*M_PI*(2*i+1+n/2)*(2*k+1) / (4 * n));
 127             s += input[i] * cos(a);
 128         }
 129         output[k] = s;
 130     }
 131 }
 132
 133
 134 float frandom(void)
 135 {
 136     return (float)((random() & 0xffff) - 32768) / 32768.0;
 137 }
 138
 139 int64_t gettime(void)
 140 {
 141     struct timeval tv;
 142     gettimeofday(&tv,NULL);
 143     return (int64_t)tv.tv_sec * 1000000 + tv.tv_usec;
 144 }
 145
 146 void check_diff(float *tab1, float *tab2, int n)
 147 {
 148     int i;
 149     double max= 0;
 150     double error= 0;
 151
 152     for(i=0;i<n;i++) {
 153         double e= fabsf(tab1[i] - tab2[i]);
 154         if (e >= 1e-3) {
 155             av_log(NULL, AV_LOG_ERROR, "ERROR %d: %f %f\n",
 156                    i, tab1[i], tab2[i]);
 157         }
 158         error+= e*e;
 159         if(e>max) max= e;
 160     }
 161     av_log(NULL, AV_LOG_INFO, "max:%f e:%g\n", max, sqrt(error)/n);
 162 }
 163
 164
 165 void help(void)
 166 {
 167     av_log(NULL, AV_LOG_INFO,"usage: fft-test [-h] [-s] [-i] [-n b]\n"
 168            "-h     print this help\n"
 169            "-s     speed test\n"
 170            "-m     (I)MDCT test\n"
 171            "-i     inverse transform test\n"
 172            "-n b   set the transform size to 2^b\n"
 173            );
 174     exit(1);
 175 }
 176
 177
 178
 179 int main(int argc, char **argv)
 180 {
 181     FFTComplex *tab, *tab1, *tab_ref;
 182     FFTSample *tabtmp, *tab2;
 183     int it, i, c;
 184     int do_speed = 0;
 185     int do_mdct = 0;
 186     int do_inverse = 0;
 187     FFTContext s1, *s = &s1;
 188     MDCTContext m1, *m = &m1;
 189     int fft_nbits, fft_size;
 190
 191     mm_flags = 0;
 192     fft_nbits = 9;
 193     for(;;) {
 194         c = getopt(argc, argv, "hsimn:");
 195         if (c == -1)
 196             break;
 197         switch(c) {
 198         case 'h':
 199             help();
 200             break;
 201         case 's':
 202             do_speed = 1;
 203             break;
 204         case 'i':
 205             do_inverse = 1;
 206             break;
 207         case 'm':
 208             do_mdct = 1;
 209             break;
 210         case 'n':
 211             fft_nbits = atoi(optarg);
 212             break;
 213         }
 214     }
 215
 216     fft_size = 1 << fft_nbits;
 217     tab = av_malloc(fft_size * sizeof(FFTComplex));
 218     tab1 = av_malloc(fft_size * sizeof(FFTComplex));
 219     tab_ref = av_malloc(fft_size * sizeof(FFTComplex));
 220     tabtmp = av_malloc(fft_size / 2 * sizeof(FFTSample));
 221     tab2 = av_malloc(fft_size * sizeof(FFTSample));
 222
 223     if (do_mdct) {
 224         if (do_inverse)
 225             av_log(NULL, AV_LOG_INFO,"IMDCT");
 226         else
 227             av_log(NULL, AV_LOG_INFO,"MDCT");
 228         ff_mdct_init(m, fft_nbits, do_inverse);
 229     } else {
 230         if (do_inverse)
 231             av_log(NULL, AV_LOG_INFO,"IFFT");
 232         else
 233             av_log(NULL, AV_LOG_INFO,"FFT");
 234         ff_fft_init(s, fft_nbits, do_inverse);
 235         fft_ref_init(fft_nbits, do_inverse);
 236     }
 237     av_log(NULL, AV_LOG_INFO," %d test\n", fft_size);
 238
 239     /* generate random data */
 240
 241     for(i=0;i<fft_size;i++) {
 242         tab1[i].re = frandom();
 243         tab1[i].im = frandom();
 244     }
 245
 246     /* checking result */
 247     av_log(NULL, AV_LOG_INFO,"Checking...\n");
 248
 249     if (do_mdct) {
 250         if (do_inverse) {
 251             imdct_ref((float *)tab_ref, (float *)tab1, fft_nbits);
 252             ff_imdct_calc(m, tab2, (float *)tab1, tabtmp);
 253             check_diff((float *)tab_ref, tab2, fft_size);
 254         } else {
 255             mdct_ref((float *)tab_ref, (float *)tab1, fft_nbits);
 256
 257             ff_mdct_calc(m, tab2, (float *)tab1, tabtmp);
 258
 259             check_diff((float *)tab_ref, tab2, fft_size / 2);
 260         }
 261     } else {
 262         memcpy(tab, tab1, fft_size * sizeof(FFTComplex));
 263         ff_fft_permute(s, tab);
 264         ff_fft_calc(s, tab);
 265
 266         fft_ref(tab_ref, tab1, fft_nbits);
 267         check_diff((float *)tab_ref, (float *)tab, fft_size * 2);
 268     }
 269
 270     /* do a speed test */
 271
 272     if (do_speed) {
 273         int64_t time_start, duration;
 274         int nb_its;
 275
 276         av_log(NULL, AV_LOG_INFO,"Speed test...\n");
 277         /* we measure during about 1 seconds */
 278         nb_its = 1;
 279         for(;;) {
 280             time_start = gettime();
 281             for(it=0;it<nb_its;it++) {
 282                 if (do_mdct) {
 283                     if (do_inverse) {
 284                         ff_imdct_calc(m, (float *)tab, (float *)tab1, tabtmp);
 285                     } else {
 286                         ff_mdct_calc(m, (float *)tab, (float *)tab1, tabtmp);
 287                     }
 288                 } else {
 289                     memcpy(tab, tab1, fft_size * sizeof(FFTComplex));
 290                     ff_fft_calc(s, tab);
 291                 }
 292             }
 293             duration = gettime() - time_start;
 294             if (duration >= 1000000)
 295                 break;
 296             nb_its *= 2;
 297         }
 298         av_log(NULL, AV_LOG_INFO,"time: %0.1f us/transform [total time=%0.2f s its=%d]\n",
 299                (double)duration / nb_its,
 300                (double)duration / 1000000.0,
 301                nb_its);
 302     }
 303
 304     if (do_mdct) {
 305         ff_mdct_end(m);
 306     } else {
 307         ff_fft_end(s);
 308     }
 309     return 0;
 310 }