2 * tables and functions for demuxing SIPR audio muxed RealMedia style
4 * This file is part of FFmpeg.
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.
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.
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
25 const unsigned char ff_sipr_subpk_size
[4] = { 29, 19, 37, 20 };
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 }
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
)
43 int n
, bs
= sub_packet_h
* framesize
* 2 / 96; // nibbles per subpacket
45 for (n
= 0; n
< 38; n
++) {
47 int i
= bs
* sipr_swaps
[n
][0];
48 int o
= bs
* sipr_swaps
[n
][1];
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;
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))));