FFmpeg
rmsipr.c
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1 /*
2  * tables and functions for demuxing SIPR audio muxed RealMedia style
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 #include <stdint.h>
22 
23 #include "rmsipr.h"
24 
25 const unsigned char ff_sipr_subpk_size[4] = { 29, 19, 37, 20 };
26 
27 static const unsigned char sipr_swaps[38][2] = {
28  { 0, 63 }, { 1, 22 }, { 2, 44 }, { 3, 90 },
29  { 5, 81 }, { 7, 31 }, { 8, 86 }, { 9, 58 },
30  { 10, 36 }, { 12, 68 }, { 13, 39 }, { 14, 73 },
31  { 15, 53 }, { 16, 69 }, { 17, 57 }, { 19, 88 },
32  { 20, 34 }, { 21, 71 }, { 24, 46 }, { 25, 94 },
33  { 26, 54 }, { 28, 75 }, { 29, 50 }, { 32, 70 },
34  { 33, 92 }, { 35, 74 }, { 38, 85 }, { 40, 56 },
35  { 42, 87 }, { 43, 65 }, { 45, 59 }, { 48, 79 },
36  { 49, 93 }, { 51, 89 }, { 55, 95 }, { 61, 76 },
37  { 67, 83 }, { 77, 80 }
38 };
39 
40 /* This can be optimized, e.g. use memcpy() if data blocks are aligned. */
41 void ff_rm_reorder_sipr_data(uint8_t *buf, int sub_packet_h, int framesize)
42 {
43  int n, bs = sub_packet_h * framesize * 2 / 96; // nibbles per subpacket
44 
45  for (n = 0; n < 38; n++) {
46  int j;
47  int i = bs * sipr_swaps[n][0];
48  int o = bs * sipr_swaps[n][1];
49 
50  /* swap 4bit-nibbles of block 'i' with 'o' */
51  for (j = 0; j < bs; j++, i++, o++) {
52  int x = (buf[i >> 1] >> (4 * (i & 1))) & 0xF,
53  y = (buf[o >> 1] >> (4 * (o & 1))) & 0xF;
54 
55  buf[o >> 1] = (x << (4 * (o & 1))) |
56  (buf[o >> 1] & (0xF << (4 * !(o & 1))));
57  buf[i >> 1] = (y << (4 * (i & 1))) |
58  (buf[i >> 1] & (0xF << (4 * !(i & 1))));
59  }
60  }
61 }
const unsigned char ff_sipr_subpk_size[4]
Definition: rmsipr.c:25
uint8_t
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:259
static const unsigned char sipr_swaps[38][2]
Definition: rmsipr.c:27
int n
Definition: avisynth_c.h:760
void * buf
Definition: avisynth_c.h:766
void ff_rm_reorder_sipr_data(uint8_t *buf, int sub_packet_h, int framesize)
Perform 4-bit block reordering for SIPR data.
Definition: rmsipr.c:41