| 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 | } |