extern/ffmpeg/libavcodec/fft-test.c

   1 /**
   2  * @file fft-test.c
   3  * FFT and MDCT tests.
   4  */
   5
   6 #include "dsputil.h"
   7 #include <math.h>
   8 #include <unistd.h>
   9 #include <sys/time.h>
  10
  11 int mm_flags;
  12
  13 /* reference fft */
  14
  15 #define MUL16(a,b) ((a) * (b))
  16
  17 #define CMAC(pre, pim, are, aim, bre, bim) \
  18 {\
  19    pre += (MUL16(are, bre) - MUL16(aim, bim));\
  20    pim += (MUL16(are, bim) + MUL16(bre, aim));\
  21 }
  22
  23 FFTComplex *exptab;
  24
  25 void fft_ref_init(int nbits, int inverse)
  26 {
  27     int n, i;
  28     float c1, s1, alpha;
  29
  30     n = 1 << nbits;
  31     exptab = av_malloc((n / 2) * sizeof(FFTComplex));
  32
  33     for(i=0;i<(n/2);i++) {
  34         alpha = 2 * M_PI * (float)i / (float)n;
  35         c1 = cos(alpha);
  36         s1 = sin(alpha);
  37         if (!inverse)
  38             s1 = -s1;
  39         exptab[i].re = c1;
  40         exptab[i].im = s1;
  41     }
  42 }
  43
  44 void fft_ref(FFTComplex *tabr, FFTComplex *tab, int nbits)
  45 {
  46     int n, i, j, k, n2;
  47     float tmp_re, tmp_im, s, c;
  48     FFTComplex *q;
  49
  50     n = 1 << nbits;
  51     n2 = n >> 1;
  52     for(i=0;i<n;i++) {
  53         tmp_re = 0;
  54         tmp_im = 0;
  55         q = tab;
  56         for(j=0;j<n;j++) {
  57             k = (i * j) & (n - 1);
  58             if (k >= n2) {
  59                 c = -exptab[k - n2].re;
  60                 s = -exptab[k - n2].im;
  61             } else {
  62                 c = exptab[k].re;
  63                 s = exptab[k].im;
  64             }
  65             CMAC(tmp_re, tmp_im, c, s, q->re, q->im);
  66             q++;
  67         }
  68         tabr[i].re = tmp_re;
  69         tabr[i].im = tmp_im;
  70     }
  71 }
  72
  73 void imdct_ref(float *out, float *in, int n)
  74 {
  75     int k, i, a;
  76     float sum, f;
  77
  78     for(i=0;i<n;i++) {
  79         sum = 0;
  80         for(k=0;k<n/2;k++) {
  81             a = (2 * i + 1 + (n / 2)) * (2 * k + 1);
  82             f = cos(M_PI * a / (double)(2 * n));
  83             sum += f * in[k];
  84         }
  85         out[i] = -sum;
  86     }
  87 }
  88
  89 /* NOTE: no normalisation by 1 / N is done */
  90 void mdct_ref(float *output, float *input, int n)
  91 {
  92     int k, i;
  93     float a, s;
  94
  95     /* do it by hand */
  96     for(k=0;k<n/2;k++) {
  97         s = 0;
  98         for(i=0;i<n;i++) {
  99             a = (2*M_PI*(2*i+1+n/2)*(2*k+1) / (4 * n));
 100             s += input[i] * cos(a);
 101         }
 102         output[k] = s;
 103     }
 104 }
 105
 106
 107 float frandom(void)
 108 {
 109     return (float)((random() & 0xffff) - 32768) / 32768.0;
 110 }
 111
 112 int64_t gettime(void)
 113 {
 114     struct timeval tv;
 115     gettimeofday(&tv,NULL);
 116     return (int64_t)tv.tv_sec * 1000000 + tv.tv_usec;
 117 }
 118
 119 void check_diff(float *tab1, float *tab2, int n)
 120 {
 121     int i;
 122
 123     for(i=0;i<n;i++) {
 124         if (fabsf(tab1[i] - tab2[i]) >= 1e-3) {
 125             av_log(NULL, AV_LOG_ERROR, "ERROR %d: %f %f\n",
 126                    i, tab1[i], tab2[i]);
 127         }
 128     }
 129 }
 130
 131
 132 void help(void)
 133 {
 134     av_log(NULL, AV_LOG_INFO,"usage: fft-test [-h] [-s] [-i] [-n b]\n"
 135            "-h     print this help\n"
 136            "-s     speed test\n"
 137            "-m     (I)MDCT test\n"
 138            "-i     inverse transform test\n"
 139            "-n b   set the transform size to 2^b\n"
 140            );
 141     exit(1);
 142 }
 143
 144
 145
 146 int main(int argc, char **argv)
 147 {
 148     FFTComplex *tab, *tab1, *tab_ref;
 149     FFTSample *tabtmp, *tab2;
 150     int it, i, c;
 151     int do_speed = 0;
 152     int do_mdct = 0;
 153     int do_inverse = 0;
 154     FFTContext s1, *s = &s1;
 155     MDCTContext m1, *m = &m1;
 156     int fft_nbits, fft_size;
 157
 158     mm_flags = 0;
 159     fft_nbits = 9;
 160     for(;;) {
 161         c = getopt(argc, argv, "hsimn:");
 162         if (c == -1)
 163             break;
 164         switch(c) {
 165         case 'h':
 166             help();
 167             break;
 168         case 's':
 169             do_speed = 1;
 170             break;
 171         case 'i':
 172             do_inverse = 1;
 173             break;
 174         case 'm':
 175             do_mdct = 1;
 176             break;
 177         case 'n':
 178             fft_nbits = atoi(optarg);
 179             break;
 180         }
 181     }
 182
 183     fft_size = 1 << fft_nbits;
 184     tab = av_malloc(fft_size * sizeof(FFTComplex));
 185     tab1 = av_malloc(fft_size * sizeof(FFTComplex));
 186     tab_ref = av_malloc(fft_size * sizeof(FFTComplex));
 187     tabtmp = av_malloc(fft_size / 2 * sizeof(FFTSample));
 188     tab2 = av_malloc(fft_size * sizeof(FFTSample));
 189
 190     if (do_mdct) {
 191         if (do_inverse)
 192             av_log(NULL, AV_LOG_INFO,"IMDCT");
 193         else
 194             av_log(NULL, AV_LOG_INFO,"MDCT");
 195         ff_mdct_init(m, fft_nbits, do_inverse);
 196     } else {
 197         if (do_inverse)
 198             av_log(NULL, AV_LOG_INFO,"IFFT");
 199         else
 200             av_log(NULL, AV_LOG_INFO,"FFT");
 201         ff_fft_init(s, fft_nbits, do_inverse);
 202         fft_ref_init(fft_nbits, do_inverse);
 203     }
 204     av_log(NULL, AV_LOG_INFO," %d test\n", fft_size);
 205
 206     /* generate random data */
 207
 208     for(i=0;i<fft_size;i++) {
 209         tab1[i].re = frandom();
 210         tab1[i].im = frandom();
 211     }
 212
 213     /* checking result */
 214     av_log(NULL, AV_LOG_INFO,"Checking...\n");
 215
 216     if (do_mdct) {
 217         if (do_inverse) {
 218             imdct_ref((float *)tab_ref, (float *)tab1, fft_size);
 219             ff_imdct_calc(m, tab2, (float *)tab1, tabtmp);
 220             check_diff((float *)tab_ref, tab2, fft_size);
 221         } else {
 222             mdct_ref((float *)tab_ref, (float *)tab1, fft_size);
 223
 224             ff_mdct_calc(m, tab2, (float *)tab1, tabtmp);
 225
 226             check_diff((float *)tab_ref, tab2, fft_size / 2);
 227         }
 228     } else {
 229         memcpy(tab, tab1, fft_size * sizeof(FFTComplex));
 230         ff_fft_permute(s, tab);
 231         ff_fft_calc(s, tab);
 232
 233         fft_ref(tab_ref, tab1, fft_nbits);
 234         check_diff((float *)tab_ref, (float *)tab, fft_size * 2);
 235     }
 236
 237     /* do a speed test */
 238
 239     if (do_speed) {
 240         int64_t time_start, duration;
 241         int nb_its;
 242
 243         av_log(NULL, AV_LOG_INFO,"Speed test...\n");
 244         /* we measure during about 1 seconds */
 245         nb_its = 1;
 246         for(;;) {
 247             time_start = gettime();
 248             for(it=0;it<nb_its;it++) {
 249                 if (do_mdct) {
 250                     if (do_inverse) {
 251                         ff_imdct_calc(m, (float *)tab, (float *)tab1, tabtmp);
 252                     } else {
 253                         ff_mdct_calc(m, (float *)tab, (float *)tab1, tabtmp);
 254                     }
 255                 } else {
 256                     memcpy(tab, tab1, fft_size * sizeof(FFTComplex));
 257                     ff_fft_calc(s, tab);
 258                 }
 259             }
 260             duration = gettime() - time_start;
 261             if (duration >= 1000000)
 262                 break;
 263             nb_its *= 2;
 264         }
 265         av_log(NULL, AV_LOG_INFO,"time: %0.1f us/transform [total time=%0.2f s its=%d]\n",
 266                (double)duration / nb_its,
 267                (double)duration / 1000000.0,
 268                nb_its);
 269     }
 270
 271     if (do_mdct) {
 272         ff_mdct_end(m);
 273     } else {
 274         ff_fft_end(s);
 275     }
 276     return 0;
 277 }