| /* |
| * tables and functions for demuxing SIPR audio muxed RealMedia style |
| * |
| * This file is part of FFmpeg. |
| * |
| * FFmpeg is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU Lesser General Public |
| * License as published by the Free Software Foundation; either |
| * version 2.1 of the License, or (at your option) any later version. |
| * |
| * FFmpeg is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| * Lesser General Public License for more details. |
| * |
| * You should have received a copy of the GNU Lesser General Public |
| * License along with FFmpeg; if not, write to the Free Software |
| * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| */ |
| |
| #include <stdint.h> |
| |
| #include "rmsipr.h" |
| |
| const unsigned char ff_sipr_subpk_size[4] = { 29, 19, 37, 20 }; |
| |
| static const unsigned char sipr_swaps[38][2] = { |
| { 0, 63 }, { 1, 22 }, { 2, 44 }, { 3, 90 }, |
| { 5, 81 }, { 7, 31 }, { 8, 86 }, { 9, 58 }, |
| { 10, 36 }, { 12, 68 }, { 13, 39 }, { 14, 73 }, |
| { 15, 53 }, { 16, 69 }, { 17, 57 }, { 19, 88 }, |
| { 20, 34 }, { 21, 71 }, { 24, 46 }, { 25, 94 }, |
| { 26, 54 }, { 28, 75 }, { 29, 50 }, { 32, 70 }, |
| { 33, 92 }, { 35, 74 }, { 38, 85 }, { 40, 56 }, |
| { 42, 87 }, { 43, 65 }, { 45, 59 }, { 48, 79 }, |
| { 49, 93 }, { 51, 89 }, { 55, 95 }, { 61, 76 }, |
| { 67, 83 }, { 77, 80 } |
| }; |
| |
| /* This can be optimized, e.g. use memcpy() if data blocks are aligned. */ |
| void ff_rm_reorder_sipr_data(uint8_t *buf, int sub_packet_h, int framesize) |
| { |
| int n, bs = sub_packet_h * framesize * 2 / 96; // nibbles per subpacket |
| |
| for (n = 0; n < 38; n++) { |
| int j; |
| int i = bs * sipr_swaps[n][0]; |
| int o = bs * sipr_swaps[n][1]; |
| |
| /* swap 4bit-nibbles of block 'i' with 'o' */ |
| for (j = 0; j < bs; j++, i++, o++) { |
| int x = (buf[i >> 1] >> (4 * (i & 1))) & 0xF, |
| y = (buf[o >> 1] >> (4 * (o & 1))) & 0xF; |
| |
| buf[o >> 1] = (x << (4 * (o & 1))) | |
| (buf[o >> 1] & (0xF << (4 * !(o & 1)))); |
| buf[i >> 1] = (y << (4 * (i & 1))) | |
| (buf[i >> 1] & (0xF << (4 * !(i & 1)))); |
| } |
| } |
| } |