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 : }