xref: /third_party/ffmpeg/libavcodec/takdsp.c (revision cabdff1a) 
1/*
2 * TAK decoder
3 * Copyright (c) 2015 Paul B Mahol
4 *
5 * This file is part of FFmpeg.
6 *
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
11 *
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22#include "libavutil/attributes.h"
23#include "takdsp.h"
24#include "config.h"
25
26static void decorrelate_ls(int32_t *p1, int32_t *p2, int length)
27{
28    int i;
29
30    for (i = 0; i < length; i++) {
31        uint32_t a = p1[i];
32        uint32_t b = p2[i];
33        p2[i]     = a + b;
34    }
35}
36
37static void decorrelate_sr(int32_t *p1, int32_t *p2, int length)
38{
39    int i;
40
41    for (i = 0; i < length; i++) {
42        uint32_t a = p1[i];
43        uint32_t b = p2[i];
44        p1[i]     = b - a;
45    }
46}
47
48static void decorrelate_sm(int32_t *p1, int32_t *p2, int length)
49{
50    int i;
51
52    for (i = 0; i < length; i++) {
53        uint32_t a = p1[i];
54        int32_t b = p2[i];
55        a        -= b >> 1;
56        p1[i]     = a;
57        p2[i]     = a + b;
58    }
59}
60
61static void decorrelate_sf(int32_t *p1, int32_t *p2, int length, int dshift, int dfactor)
62{
63    int i;
64
65    for (i = 0; i < length; i++) {
66        uint32_t a = p1[i];
67        int32_t b = p2[i];
68        b         = (unsigned)((int)(dfactor * (unsigned)(b >> dshift) + 128) >> 8) << dshift;
69        p1[i]     = b - a;
70    }
71}
72
73av_cold void ff_takdsp_init(TAKDSPContext *c)
74{
75    c->decorrelate_ls = decorrelate_ls;
76    c->decorrelate_sr = decorrelate_sr;
77    c->decorrelate_sm = decorrelate_sm;
78    c->decorrelate_sf = decorrelate_sf;
79
80#if ARCH_X86
81    ff_takdsp_init_x86(c);
82#endif
83}
84