Line data Source code
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 88 : void ff_rm_reorder_sipr_data(uint8_t *buf, int sub_packet_h, int framesize)
42 : {
43 88 : int n, bs = sub_packet_h * framesize * 2 / 96; // nibbles per subpacket
44 :
45 3432 : for (n = 0; n < 38; n++) {
46 : int j;
47 3344 : int i = bs * sipr_swaps[n][0];
48 3344 : int o = bs * sipr_swaps[n][1];
49 :
50 : /* swap 4bit-nibbles of block 'i' with 'o' */
51 120764 : for (j = 0; j < bs; j++, i++, o++) {
52 117420 : int x = (buf[i >> 1] >> (4 * (i & 1))) & 0xF,
53 117420 : y = (buf[o >> 1] >> (4 * (o & 1))) & 0xF;
54 :
55 234840 : buf[o >> 1] = (x << (4 * (o & 1))) |
56 117420 : (buf[o >> 1] & (0xF << (4 * !(o & 1))));
57 234840 : buf[i >> 1] = (y << (4 * (i & 1))) |
58 117420 : (buf[i >> 1] & (0xF << (4 * !(i & 1))));
59 : }
60 : }
61 88 : }
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