1 /*
2 * Shared functions between AMR codecs
3 *
4 * Copyright (c) 2010 Marcelo Galvao Povoa
5 *
6 * This file is part of FFmpeg.
7 *
8 * FFmpeg is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Lesser General Public
10 * License as published by the Free Software Foundation; either
11 * version 2.1 of the License, or (at your option) any later version.
12 *
13 * FFmpeg is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Lesser General Public License for more details.
17 *
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with FFmpeg; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21 */
22
23 #ifndef AVCODEC_AMR_H
24 #define AVCODEC_AMR_H
25
26 #include <string.h>
27
28 #include "avcodec.h"
29
30 #ifdef AMR_USE_16BIT_TABLES
31 typedef uint16_t R_TABLE_TYPE;
32 #else
33 typedef uint8_t R_TABLE_TYPE;
34 #endif
35
36 /**
37 * Fill the frame structure variables from bitstream by parsing the
38 * given reordering table that uses the following format:
39 *
40 * Each field (16 bits) in the AMR Frame is stored as:
41 * - one byte for the number of bits in the field
42 * - one byte for the field index
43 * - then, one byte for each bit of the field (from most-significant to least)
44 * of the position of that bit in the AMR frame.
45 *
46 * @param out pointer to the frame struct
47 * @param size the size in bytes of the frame struct
48 * @param data input bitstream after the frame header
49 * @param ord_table the reordering table as above
50 */
ff_amr_bit_reorder(uint16_t * out,int size,const uint8_t * data,const R_TABLE_TYPE * ord_table)51 static inline void ff_amr_bit_reorder(uint16_t *out, int size,
52 const uint8_t *data,
53 const R_TABLE_TYPE *ord_table)
54 {
55 int field_size;
56
57 memset(out, 0, size);
58 while ((field_size = *ord_table++)) {
59 int field = 0;
60 int field_offset = *ord_table++;
61 while (field_size--) {
62 int bit = *ord_table++;
63 field <<= 1;
64 field |= data[bit >> 3] >> (bit & 7) & 1;
65 }
66 out[field_offset >> 1] = field;
67 }
68 }
69
70 #endif /* AVCODEC_AMR_H */
71