Split global .gitignore file into per-directory files
[libav.git] / libavcodec / tests / iirfilter.c
1 /*
2 * This file is part of Libav.
3 *
4 * Libav is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU Lesser General Public
6 * License as published by the Free Software Foundation; either
7 * version 2.1 of the License, or (at your option) any later version.
8 *
9 * Libav is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * Lesser General Public License for more details.
13 *
14 * You should have received a copy of the GNU Lesser General Public
15 * License along with Libav; if not, write to the Free Software
16 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
17 */
18
19 #include <math.h>
20 #include <stdint.h>
21 #include <stdio.h>
22
23 #include "libavutil/libm.h"
24
25 #include "libavcodec/iirfilter.h"
26
27 #define FILT_ORDER 4
28 #define SIZE 1024
29
30 int main(void)
31 {
32 struct FFIIRFilterCoeffs *fcoeffs = NULL;
33 struct FFIIRFilterState *fstate = NULL;
34 float cutoff_coeff = 0.4;
35 int16_t x[SIZE], y[SIZE];
36 int i;
37
38 fcoeffs = ff_iir_filter_init_coeffs(NULL, FF_FILTER_TYPE_BUTTERWORTH,
39 FF_FILTER_MODE_LOWPASS, FILT_ORDER,
40 cutoff_coeff, 0.0, 0.0);
41 fstate = ff_iir_filter_init_state(FILT_ORDER);
42
43 for (i = 0; i < SIZE; i++)
44 x[i] = lrint(0.75 * INT16_MAX * sin(0.5 * M_PI * i * i / SIZE));
45
46 ff_iir_filter(fcoeffs, fstate, SIZE, x, 1, y, 1);
47
48 for (i = 0; i < SIZE; i++)
49 printf("%6d %6d\n", x[i], y[i]);
50
51 ff_iir_filter_free_coeffs(fcoeffs);
52 ff_iir_filter_free_state(fstate);
53 return 0;
54 }