blob: 6cd80228b11c002ccc8a7062387f07c8f1e85688
1 | /* |
2 | * This file is part of FFmpeg. |
3 | * |
4 | * FFmpeg 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 | * FFmpeg 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 FFmpeg; if not, write to the Free Software |
16 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
17 | */ |
18 | |
19 | #include <stdint.h> |
20 | #include "libavutil/avassert.h" |
21 | #include "avfilter.h" |
22 | #include "generate_wave_table.h" |
23 | |
24 | void ff_generate_wave_table(enum WaveType wave_type, |
25 | enum AVSampleFormat sample_fmt, |
26 | void *table, int table_size, |
27 | double min, double max, double phase) |
28 | { |
29 | uint32_t i, phase_offset = phase / M_PI / 2 * table_size + 0.5; |
30 | |
31 | for (i = 0; i < table_size; i++) { |
32 | uint32_t point = (i + phase_offset) % table_size; |
33 | double d; |
34 | |
35 | switch (wave_type) { |
36 | case WAVE_SIN: |
37 | d = (sin((double)point / table_size * 2 * M_PI) + 1) / 2; |
38 | break; |
39 | case WAVE_TRI: |
40 | d = (double)point * 2 / table_size; |
41 | switch (4 * point / table_size) { |
42 | case 0: d = d + 0.5; break; |
43 | case 1: |
44 | case 2: d = 1.5 - d; break; |
45 | case 3: d = d - 1.5; break; |
46 | } |
47 | break; |
48 | default: |
49 | av_assert0(0); |
50 | } |
51 | |
52 | d = d * (max - min) + min; |
53 | switch (sample_fmt) { |
54 | case AV_SAMPLE_FMT_FLT: { |
55 | float *fp = (float *)table; |
56 | *fp++ = (float)d; |
57 | table = fp; |
58 | continue; } |
59 | case AV_SAMPLE_FMT_DBL: { |
60 | double *dp = (double *)table; |
61 | *dp++ = d; |
62 | table = dp; |
63 | continue; } |
64 | } |
65 | |
66 | d += d < 0 ? -0.5 : 0.5; |
67 | switch (sample_fmt) { |
68 | case AV_SAMPLE_FMT_S16: { |
69 | int16_t *sp = table; |
70 | *sp++ = (int16_t)d; |
71 | table = sp; |
72 | continue; } |
73 | case AV_SAMPLE_FMT_S32: { |
74 | int32_t *ip = table; |
75 | *ip++ = (int32_t)d; |
76 | table = ip; |
77 | continue; } |
78 | default: |
79 | av_assert0(0); |
80 | } |
81 | } |
82 | } |
83 |