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fft-test.c
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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
23  * FFT and MDCT tests.
24  */
25 
26 #include "config.h"
27 
28 #include <math.h>
29 #if HAVE_UNISTD_H
30 #include <unistd.h>
31 #endif
32 #include <stdio.h>
33 #include <stdlib.h>
34 #include <string.h>
35 
36 #include "libavutil/cpu.h"
37 #include "libavutil/lfg.h"
38 #include "libavutil/log.h"
39 #include "libavutil/mathematics.h"
40 #include "libavutil/time.h"
41 
42 #include "fft.h"
43 #if FFT_FLOAT
44 #include "dct.h"
45 #include "rdft.h"
46 #endif
47 
48 /* reference fft */
49 
50 #define MUL16(a, b) ((a) * (b))
51 
52 #define CMAC(pre, pim, are, aim, bre, bim) \
53  { \
54  pre += (MUL16(are, bre) - MUL16(aim, bim)); \
55  pim += (MUL16(are, bim) + MUL16(bre, aim)); \
56  }
57 
58 #if FFT_FLOAT
59 #define RANGE 1.0
60 #define REF_SCALE(x, bits) (x)
61 #define FMT "%10.6f"
62 #elif FFT_FIXED_32
63 #define RANGE 8388608
64 #define REF_SCALE(x, bits) (x)
65 #define FMT "%6d"
66 #else
67 #define RANGE 16384
68 #define REF_SCALE(x, bits) ((x) / (1 << (bits)))
69 #define FMT "%6d"
70 #endif
71 
72 static struct {
73  float re, im;
74 } *exptab;
75 
76 static int fft_ref_init(int nbits, int inverse)
77 {
78  int i, n = 1 << nbits;
79 
80  exptab = av_malloc_array((n / 2), sizeof(*exptab));
81  if (!exptab)
82  return AVERROR(ENOMEM);
83 
84  for (i = 0; i < (n / 2); i++) {
85  double alpha = 2 * M_PI * (float) i / (float) n;
86  double c1 = cos(alpha), s1 = sin(alpha);
87  if (!inverse)
88  s1 = -s1;
89  exptab[i].re = c1;
90  exptab[i].im = s1;
91  }
92  return 0;
93 }
94 
95 static void fft_ref(FFTComplex *tabr, FFTComplex *tab, int nbits)
96 {
97  int i, j;
98  int n = 1 << nbits;
99  int n2 = n >> 1;
100 
101  for (i = 0; i < n; i++) {
102  double tmp_re = 0, tmp_im = 0;
103  FFTComplex *q = tab;
104  for (j = 0; j < n; j++) {
105  double s, c;
106  int k = (i * j) & (n - 1);
107  if (k >= n2) {
108  c = -exptab[k - n2].re;
109  s = -exptab[k - n2].im;
110  } else {
111  c = exptab[k].re;
112  s = exptab[k].im;
113  }
114  CMAC(tmp_re, tmp_im, c, s, q->re, q->im);
115  q++;
116  }
117  tabr[i].re = REF_SCALE(tmp_re, nbits);
118  tabr[i].im = REF_SCALE(tmp_im, nbits);
119  }
120 }
121 
122 #if CONFIG_MDCT
123 static void imdct_ref(FFTSample *out, FFTSample *in, int nbits)
124 {
125  int i, k, n = 1 << nbits;
126 
127  for (i = 0; i < n; i++) {
128  double sum = 0;
129  for (k = 0; k < n / 2; k++) {
130  int a = (2 * i + 1 + (n / 2)) * (2 * k + 1);
131  double f = cos(M_PI * a / (double) (2 * n));
132  sum += f * in[k];
133  }
134  out[i] = REF_SCALE(-sum, nbits - 2);
135  }
136 }
137 
138 /* NOTE: no normalisation by 1 / N is done */
139 static void mdct_ref(FFTSample *output, FFTSample *input, int nbits)
140 {
141  int i, k, n = 1 << nbits;
142 
143  /* do it by hand */
144  for (k = 0; k < n / 2; k++) {
145  double s = 0;
146  for (i = 0; i < n; i++) {
147  double a = (2 * M_PI * (2 * i + 1 + n / 2) * (2 * k + 1) / (4 * n));
148  s += input[i] * cos(a);
149  }
150  output[k] = REF_SCALE(s, nbits - 1);
151  }
152 }
153 #endif /* CONFIG_MDCT */
154 
155 #if FFT_FLOAT
156 #if CONFIG_DCT
157 static void idct_ref(FFTSample *output, FFTSample *input, int nbits)
158 {
159  int i, k, n = 1 << nbits;
160 
161  /* do it by hand */
162  for (i = 0; i < n; i++) {
163  double s = 0.5 * input[0];
164  for (k = 1; k < n; k++) {
165  double a = M_PI * k * (i + 0.5) / n;
166  s += input[k] * cos(a);
167  }
168  output[i] = 2 * s / n;
169  }
170 }
171 
172 static void dct_ref(FFTSample *output, FFTSample *input, int nbits)
173 {
174  int i, k, n = 1 << nbits;
175 
176  /* do it by hand */
177  for (k = 0; k < n; k++) {
178  double s = 0;
179  for (i = 0; i < n; i++) {
180  double a = M_PI * k * (i + 0.5) / n;
181  s += input[i] * cos(a);
182  }
183  output[k] = s;
184  }
185 }
186 #endif /* CONFIG_DCT */
187 #endif /* FFT_FLOAT */
188 
189 static FFTSample frandom(AVLFG *prng)
190 {
191  return (int16_t) av_lfg_get(prng) / 32768.0 * RANGE;
192 }
193 
194 static int check_diff(FFTSample *tab1, FFTSample *tab2, int n, double scale)
195 {
196  int i, err = 0;
197  double error = 0, max = 0;
198 
199  for (i = 0; i < n; i++) {
200  double e = fabsf(tab1[i] - (tab2[i] / scale)) / RANGE;
201  if (e >= 1e-3) {
202  av_log(NULL, AV_LOG_ERROR, "ERROR %5d: "FMT" "FMT"\n",
203  i, tab1[i], tab2[i]);
204  err = 1;
205  }
206  error += e * e;
207  if (e > max)
208  max = e;
209  }
210  av_log(NULL, AV_LOG_INFO, "max:%f e:%g\n", max, sqrt(error / n));
211  return err;
212 }
213 
214 static void help(void)
215 {
216  av_log(NULL, AV_LOG_INFO,
217  "usage: fft-test [-h] [-s] [-i] [-n b]\n"
218  "-h print this help\n"
219  "-s speed test\n"
220  "-m (I)MDCT test\n"
221  "-d (I)DCT test\n"
222  "-r (I)RDFT test\n"
223  "-i inverse transform test\n"
224  "-n b set the transform size to 2^b\n"
225  "-f x set scale factor for output data of (I)MDCT to x\n");
226 }
227 
228 enum tf_transform {
229  TRANSFORM_FFT,
230  TRANSFORM_MDCT,
231  TRANSFORM_RDFT,
232  TRANSFORM_DCT,
233 };
234 
235 #if !HAVE_GETOPT
236 #include "compat/getopt.c"
237 #endif
238 
239 int main(int argc, char **argv)
240 {
241  FFTComplex *tab, *tab1, *tab_ref;
242  FFTSample *tab2;
243  enum tf_transform transform = TRANSFORM_FFT;
244  FFTContext m, s;
245 #if FFT_FLOAT
246  RDFTContext r;
247  DCTContext d;
248 #endif /* FFT_FLOAT */
249  int it, i, err = 1;
250  int do_speed = 0, do_inverse = 0;
251  int fft_nbits = 9, fft_size;
252  double scale = 1.0;
253  AVLFG prng;
254 
255  av_lfg_init(&prng, 1);
256 
257  for (;;) {
258  int c = getopt(argc, argv, "hsimrdn:f:c:");
259  if (c == -1)
260  break;
261  switch (c) {
262  case 'h':
263  help();
264  return 1;
265  case 's':
266  do_speed = 1;
267  break;
268  case 'i':
269  do_inverse = 1;
270  break;
271  case 'm':
272  transform = TRANSFORM_MDCT;
273  break;
274  case 'r':
275  transform = TRANSFORM_RDFT;
276  break;
277  case 'd':
278  transform = TRANSFORM_DCT;
279  break;
280  case 'n':
281  fft_nbits = atoi(optarg);
282  break;
283  case 'f':
284  scale = atof(optarg);
285  break;
286  case 'c':
287  {
288  int cpuflags = av_get_cpu_flags();
289 
290  if (av_parse_cpu_caps(&cpuflags, optarg) < 0)
291  return 1;
292 
293  av_force_cpu_flags(cpuflags);
294  break;
295  }
296  }
297  }
298 
299  fft_size = 1 << fft_nbits;
300  tab = av_malloc_array(fft_size, sizeof(FFTComplex));
301  tab1 = av_malloc_array(fft_size, sizeof(FFTComplex));
302  tab_ref = av_malloc_array(fft_size, sizeof(FFTComplex));
303  tab2 = av_malloc_array(fft_size, sizeof(FFTSample));
304 
305  if (!(tab && tab1 && tab_ref && tab2))
306  goto cleanup;
307 
308  switch (transform) {
309 #if CONFIG_MDCT
310  case TRANSFORM_MDCT:
311  av_log(NULL, AV_LOG_INFO, "Scale factor is set to %f\n", scale);
312  if (do_inverse)
313  av_log(NULL, AV_LOG_INFO, "IMDCT");
314  else
315  av_log(NULL, AV_LOG_INFO, "MDCT");
316  ff_mdct_init(&m, fft_nbits, do_inverse, scale);
317  break;
318 #endif /* CONFIG_MDCT */
319  case TRANSFORM_FFT:
320  if (do_inverse)
321  av_log(NULL, AV_LOG_INFO, "IFFT");
322  else
323  av_log(NULL, AV_LOG_INFO, "FFT");
324  ff_fft_init(&s, fft_nbits, do_inverse);
325  if ((err = fft_ref_init(fft_nbits, do_inverse)) < 0)
326  goto cleanup;
327  break;
328 #if FFT_FLOAT
329 # if CONFIG_RDFT
330  case TRANSFORM_RDFT:
331  if (do_inverse)
332  av_log(NULL, AV_LOG_INFO, "IDFT_C2R");
333  else
334  av_log(NULL, AV_LOG_INFO, "DFT_R2C");
335  ff_rdft_init(&r, fft_nbits, do_inverse ? IDFT_C2R : DFT_R2C);
336  if ((err = fft_ref_init(fft_nbits, do_inverse)) < 0)
337  goto cleanup;
338  break;
339 # endif /* CONFIG_RDFT */
340 # if CONFIG_DCT
341  case TRANSFORM_DCT:
342  if (do_inverse)
343  av_log(NULL, AV_LOG_INFO, "DCT_III");
344  else
345  av_log(NULL, AV_LOG_INFO, "DCT_II");
346  ff_dct_init(&d, fft_nbits, do_inverse ? DCT_III : DCT_II);
347  break;
348 # endif /* CONFIG_DCT */
349 #endif /* FFT_FLOAT */
350  default:
351  av_log(NULL, AV_LOG_ERROR, "Requested transform not supported\n");
352  goto cleanup;
353  }
354  av_log(NULL, AV_LOG_INFO, " %d test\n", fft_size);
355 
356  /* generate random data */
357 
358  for (i = 0; i < fft_size; i++) {
359  tab1[i].re = frandom(&prng);
360  tab1[i].im = frandom(&prng);
361  }
362 
363  /* checking result */
364  av_log(NULL, AV_LOG_INFO, "Checking...\n");
365 
366  switch (transform) {
367 #if CONFIG_MDCT
368  case TRANSFORM_MDCT:
369  if (do_inverse) {
370  imdct_ref(&tab_ref->re, &tab1->re, fft_nbits);
371  m.imdct_calc(&m, tab2, &tab1->re);
372  err = check_diff(&tab_ref->re, tab2, fft_size, scale);
373  } else {
374  mdct_ref(&tab_ref->re, &tab1->re, fft_nbits);
375  m.mdct_calc(&m, tab2, &tab1->re);
376  err = check_diff(&tab_ref->re, tab2, fft_size / 2, scale);
377  }
378  break;
379 #endif /* CONFIG_MDCT */
380  case TRANSFORM_FFT:
381  memcpy(tab, tab1, fft_size * sizeof(FFTComplex));
382  s.fft_permute(&s, tab);
383  s.fft_calc(&s, tab);
384 
385  fft_ref(tab_ref, tab1, fft_nbits);
386  err = check_diff(&tab_ref->re, &tab->re, fft_size * 2, 1.0);
387  break;
388 #if FFT_FLOAT
389 #if CONFIG_RDFT
390  case TRANSFORM_RDFT:
391  {
392  int fft_size_2 = fft_size >> 1;
393  if (do_inverse) {
394  tab1[0].im = 0;
395  tab1[fft_size_2].im = 0;
396  for (i = 1; i < fft_size_2; i++) {
397  tab1[fft_size_2 + i].re = tab1[fft_size_2 - i].re;
398  tab1[fft_size_2 + i].im = -tab1[fft_size_2 - i].im;
399  }
400 
401  memcpy(tab2, tab1, fft_size * sizeof(FFTSample));
402  tab2[1] = tab1[fft_size_2].re;
403 
404  r.rdft_calc(&r, tab2);
405  fft_ref(tab_ref, tab1, fft_nbits);
406  for (i = 0; i < fft_size; i++) {
407  tab[i].re = tab2[i];
408  tab[i].im = 0;
409  }
410  err = check_diff(&tab_ref->re, &tab->re, fft_size * 2, 0.5);
411  } else {
412  for (i = 0; i < fft_size; i++) {
413  tab2[i] = tab1[i].re;
414  tab1[i].im = 0;
415  }
416  r.rdft_calc(&r, tab2);
417  fft_ref(tab_ref, tab1, fft_nbits);
418  tab_ref[0].im = tab_ref[fft_size_2].re;
419  err = check_diff(&tab_ref->re, tab2, fft_size, 1.0);
420  }
421  break;
422  }
423 #endif /* CONFIG_RDFT */
424 #if CONFIG_DCT
425  case TRANSFORM_DCT:
426  memcpy(tab, tab1, fft_size * sizeof(FFTComplex));
427  d.dct_calc(&d, &tab->re);
428  if (do_inverse)
429  idct_ref(&tab_ref->re, &tab1->re, fft_nbits);
430  else
431  dct_ref(&tab_ref->re, &tab1->re, fft_nbits);
432  err = check_diff(&tab_ref->re, &tab->re, fft_size, 1.0);
433  break;
434 #endif /* CONFIG_DCT */
435 #endif /* FFT_FLOAT */
436  }
437 
438  /* do a speed test */
439 
440  if (do_speed) {
441  int64_t time_start, duration;
442  int nb_its;
443 
444  av_log(NULL, AV_LOG_INFO, "Speed test...\n");
445  /* we measure during about 1 seconds */
446  nb_its = 1;
447  for (;;) {
448  time_start = av_gettime_relative();
449  for (it = 0; it < nb_its; it++) {
450  switch (transform) {
451  case TRANSFORM_MDCT:
452  if (do_inverse)
453  m.imdct_calc(&m, &tab->re, &tab1->re);
454  else
455  m.mdct_calc(&m, &tab->re, &tab1->re);
456  break;
457  case TRANSFORM_FFT:
458  memcpy(tab, tab1, fft_size * sizeof(FFTComplex));
459  s.fft_calc(&s, tab);
460  break;
461 #if FFT_FLOAT
462  case TRANSFORM_RDFT:
463  memcpy(tab2, tab1, fft_size * sizeof(FFTSample));
464  r.rdft_calc(&r, tab2);
465  break;
466  case TRANSFORM_DCT:
467  memcpy(tab2, tab1, fft_size * sizeof(FFTSample));
468  d.dct_calc(&d, tab2);
469  break;
470 #endif /* FFT_FLOAT */
471  }
472  }
473  duration = av_gettime_relative() - time_start;
474  if (duration >= 1000000)
475  break;
476  nb_its *= 2;
477  }
478  av_log(NULL, AV_LOG_INFO,
479  "time: %0.1f us/transform [total time=%0.2f s its=%d]\n",
480  (double) duration / nb_its,
481  (double) duration / 1000000.0,
482  nb_its);
483  }
484 
485  switch (transform) {
486 #if CONFIG_MDCT
487  case TRANSFORM_MDCT:
488  ff_mdct_end(&m);
489  break;
490 #endif /* CONFIG_MDCT */
491  case TRANSFORM_FFT:
492  ff_fft_end(&s);
493  break;
494 #if FFT_FLOAT
495 # if CONFIG_RDFT
496  case TRANSFORM_RDFT:
497  ff_rdft_end(&r);
498  break;
499 # endif /* CONFIG_RDFT */
500 # if CONFIG_DCT
501  case TRANSFORM_DCT:
502  ff_dct_end(&d);
503  break;
504 # endif /* CONFIG_DCT */
505 #endif /* FFT_FLOAT */
506  }
507 
508 cleanup:
509  av_free(tab);
510  av_free(tab1);
511  av_free(tab2);
512  av_free(tab_ref);
513  av_free(exptab);
514 
515  if (err)
516  printf("Error: %d.\n", err);
517 
518  return !!err;
519 }
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