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