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 libavcodec/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/* reference fft */
37
38#define MUL16(a,b) ((a) * (b))
39
40#define CMAC(pre, pim, are, aim, bre, bim) \
41{\
42   pre += (MUL16(are, bre) - MUL16(aim, bim));\
43   pim += (MUL16(are, bim) + MUL16(bre, aim));\
44}
45
46FFTComplex *exptab;
47
48void fft_ref_init(int nbits, int inverse)
49{
50    int n, i;
51    double c1, s1, alpha;
52
53    n = 1 << nbits;
54    exptab = av_malloc((n / 2) * sizeof(FFTComplex));
55
56    for(i=0;i<(n/2);i++) {
57        alpha = 2 * M_PI * (float)i / (float)n;
58        c1 = cos(alpha);
59        s1 = sin(alpha);
60        if (!inverse)
61            s1 = -s1;
62        exptab[i].re = c1;
63        exptab[i].im = s1;
64    }
65}
66
67void fft_ref(FFTComplex *tabr, FFTComplex *tab, int nbits)
68{
69    int n, i, j, k, n2;
70    double tmp_re, tmp_im, s, c;
71    FFTComplex *q;
72
73    n = 1 << nbits;
74    n2 = n >> 1;
75    for(i=0;i<n;i++) {
76        tmp_re = 0;
77        tmp_im = 0;
78        q = tab;
79        for(j=0;j<n;j++) {
80            k = (i * j) & (n - 1);
81            if (k >= n2) {
82                c = -exptab[k - n2].re;
83                s = -exptab[k - n2].im;
84            } else {
85                c = exptab[k].re;
86                s = exptab[k].im;
87            }
88            CMAC(tmp_re, tmp_im, c, s, q->re, q->im);
89            q++;
90        }
91        tabr[i].re = tmp_re;
92        tabr[i].im = tmp_im;
93    }
94}
95
96void imdct_ref(float *out, float *in, int nbits)
97{
98    int n = 1<<nbits;
99    int k, i, a;
100    double sum, f;
101
102    for(i=0;i<n;i++) {
103        sum = 0;
104        for(k=0;k<n/2;k++) {
105            a = (2 * i + 1 + (n / 2)) * (2 * k + 1);
106            f = cos(M_PI * a / (double)(2 * n));
107            sum += f * in[k];
108        }
109        out[i] = -sum;
110    }
111}
112
113/* NOTE: no normalisation by 1 / N is done */
114void mdct_ref(float *output, float *input, int nbits)
115{
116    int n = 1<<nbits;
117    int k, i;
118    double a, s;
119
120    /* do it by hand */
121    for(k=0;k<n/2;k++) {
122        s = 0;
123        for(i=0;i<n;i++) {
124            a = (2*M_PI*(2*i+1+n/2)*(2*k+1) / (4 * n));
125            s += input[i] * cos(a);
126        }
127        output[k] = s;
128    }
129}
130
131
132float frandom(void)
133{
134    return (float)((random() & 0xffff) - 32768) / 32768.0;
135}
136
137int64_t gettime(void)
138{
139    struct timeval tv;
140    gettimeofday(&tv,NULL);
141    return (int64_t)tv.tv_sec * 1000000 + tv.tv_usec;
142}
143
144void check_diff(float *tab1, float *tab2, int n)
145{
146    int i;
147    double max= 0;
148    double error= 0;
149
150    for(i=0;i<n;i++) {
151        double e= fabsf(tab1[i] - tab2[i]);
152        if (e >= 1e-3) {
153            av_log(NULL, AV_LOG_ERROR, "ERROR %d: %f %f\n",
154                   i, tab1[i], tab2[i]);
155        }
156        error+= e*e;
157        if(e>max) max= e;
158    }
159    av_log(NULL, AV_LOG_INFO, "max:%f e:%g\n", max, sqrt(error)/n);
160}
161
162
163void help(void)
164{
165    av_log(NULL, AV_LOG_INFO,"usage: fft-test [-h] [-s] [-i] [-n b]\n"
166           "-h     print this help\n"
167           "-s     speed test\n"
168           "-m     (I)MDCT test\n"
169           "-i     inverse transform test\n"
170           "-n b   set the transform size to 2^b\n"
171           );
172    exit(1);
173}
174
175
176
177int main(int argc, char **argv)
178{
179    FFTComplex *tab, *tab1, *tab_ref;
180    FFTSample *tab2;
181    int it, i, c;
182    int do_speed = 0;
183    int do_mdct = 0;
184    int do_inverse = 0;
185    FFTContext s1, *s = &s1;
186    MDCTContext m1, *m = &m1;
187    int fft_nbits, fft_size;
188
189    fft_nbits = 9;
190    for(;;) {
191        c = getopt(argc, argv, "hsimn:");
192        if (c == -1)
193            break;
194        switch(c) {
195        case 'h':
196            help();
197            break;
198        case 's':
199            do_speed = 1;
200            break;
201        case 'i':
202            do_inverse = 1;
203            break;
204        case 'm':
205            do_mdct = 1;
206            break;
207        case 'n':
208            fft_nbits = atoi(optarg);
209            break;
210        }
211    }
212
213    fft_size = 1 << fft_nbits;
214    tab = av_malloc(fft_size * sizeof(FFTComplex));
215    tab1 = av_malloc(fft_size * sizeof(FFTComplex));
216    tab_ref = av_malloc(fft_size * sizeof(FFTComplex));
217    tab2 = av_malloc(fft_size * sizeof(FFTSample));
218
219    if (do_mdct) {
220        if (do_inverse)
221            av_log(NULL, AV_LOG_INFO,"IMDCT");
222        else
223            av_log(NULL, AV_LOG_INFO,"MDCT");
224        ff_mdct_init(m, fft_nbits, do_inverse);
225    } else {
226        if (do_inverse)
227            av_log(NULL, AV_LOG_INFO,"IFFT");
228        else
229            av_log(NULL, AV_LOG_INFO,"FFT");
230        ff_fft_init(s, fft_nbits, do_inverse);
231        fft_ref_init(fft_nbits, do_inverse);
232    }
233    av_log(NULL, AV_LOG_INFO," %d test\n", fft_size);
234
235    /* generate random data */
236
237    for(i=0;i<fft_size;i++) {
238        tab1[i].re = frandom();
239        tab1[i].im = frandom();
240    }
241
242    /* checking result */
243    av_log(NULL, AV_LOG_INFO,"Checking...\n");
244
245    if (do_mdct) {
246        if (do_inverse) {
247            imdct_ref((float *)tab_ref, (float *)tab1, fft_nbits);
248            ff_imdct_calc(m, tab2, (float *)tab1);
249            check_diff((float *)tab_ref, tab2, fft_size);
250        } else {
251            mdct_ref((float *)tab_ref, (float *)tab1, fft_nbits);
252
253            ff_mdct_calc(m, tab2, (float *)tab1);
254
255            check_diff((float *)tab_ref, tab2, fft_size / 2);
256        }
257    } else {
258        memcpy(tab, tab1, fft_size * sizeof(FFTComplex));
259        ff_fft_permute(s, tab);
260        ff_fft_calc(s, tab);
261
262        fft_ref(tab_ref, tab1, fft_nbits);
263        check_diff((float *)tab_ref, (float *)tab, fft_size * 2);
264    }
265
266    /* do a speed test */
267
268    if (do_speed) {
269        int64_t time_start, duration;
270        int nb_its;
271
272        av_log(NULL, AV_LOG_INFO,"Speed test...\n");
273        /* we measure during about 1 seconds */
274        nb_its = 1;
275        for(;;) {
276            time_start = gettime();
277            for(it=0;it<nb_its;it++) {
278                if (do_mdct) {
279                    if (do_inverse) {
280                        ff_imdct_calc(m, (float *)tab, (float *)tab1);
281                    } else {
282                        ff_mdct_calc(m, (float *)tab, (float *)tab1);
283                    }
284                } else {
285                    memcpy(tab, tab1, fft_size * sizeof(FFTComplex));
286                    ff_fft_calc(s, tab);
287                }
288            }
289            duration = gettime() - time_start;
290            if (duration >= 1000000)
291                break;
292            nb_its *= 2;
293        }
294        av_log(NULL, AV_LOG_INFO,"time: %0.1f us/transform [total time=%0.2f s its=%d]\n",
295               (double)duration / nb_its,
296               (double)duration / 1000000.0,
297               nb_its);
298    }
299
300    if (do_mdct) {
301        ff_mdct_end(m);
302    } else {
303        ff_fft_end(s);
304    }
305    return 0;
306}
307