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2ba45a60 DM |
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 | } |