FFmpeg
 All Data Structures Namespaces Files Functions Variables Typedefs Enumerations Enumerator Macros Groups Pages
mpegaudiotab.h
Go to the documentation of this file.
1 /*
2  * mpeg audio layer 2 tables. Most of them come from the mpeg audio
3  * specification.
4  *
5  * Copyright (c) 2000, 2001 Fabrice Bellard
6  *
7  * This file is part of FFmpeg.
8  *
9  * FFmpeg is free software; you can redistribute it and/or
10  * modify it under the terms of the GNU Lesser General Public
11  * License as published by the Free Software Foundation; either
12  * version 2.1 of the License, or (at your option) any later version.
13  *
14  * FFmpeg is distributed in the hope that it will be useful,
15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17  * Lesser General Public License for more details.
18  *
19  * You should have received a copy of the GNU Lesser General Public
20  * License along with FFmpeg; if not, write to the Free Software
21  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
22  */
23 
24 /**
25  * @file
26  * mpeg audio layer 2 tables.
27  * Most of them come from the mpeg audio specification.
28  */
29 
30 #ifndef AVCODEC_MPEGAUDIOTAB_H
31 #define AVCODEC_MPEGAUDIOTAB_H
32 
33 #include <stdint.h>
34 #include "mpegaudio.h"
35 
36 #define SQRT2 1.41421356237309514547
37 
38 static const int costab32[30] = {
39  FIX(0.54119610014619701222),
40  FIX(1.3065629648763763537),
41 
42  FIX(0.50979557910415917998),
43  FIX(2.5629154477415054814),
44  FIX(0.89997622313641556513),
45  FIX(0.60134488693504528634),
46 
47  FIX(0.5024192861881556782),
48  FIX(5.1011486186891552563),
49  FIX(0.78815462345125020249),
50  FIX(0.64682178335999007679),
51  FIX(0.56694403481635768927),
52  FIX(1.0606776859903470633),
53  FIX(1.7224470982383341955),
54  FIX(0.52249861493968885462),
55 
56  FIX(10.19000812354803287),
57  FIX(0.674808341455005678),
58  FIX(1.1694399334328846596),
59  FIX(0.53104259108978413284),
60  FIX(2.0577810099534108446),
61  FIX(0.58293496820613388554),
62  FIX(0.83934964541552681272),
63  FIX(0.50547095989754364798),
64  FIX(3.4076084184687189804),
65  FIX(0.62250412303566482475),
66  FIX(0.97256823786196078263),
67  FIX(0.51544730992262455249),
68  FIX(1.4841646163141661852),
69  FIX(0.5531038960344445421),
70  FIX(0.74453627100229857749),
71  FIX(0.5006029982351962726),
72 };
73 
74 static const int bitinv32[32] = {
75  0, 16, 8, 24, 4, 20, 12, 28,
76  2, 18, 10, 26, 6, 22, 14, 30,
77  1, 17, 9, 25, 5, 21, 13, 29,
78  3, 19, 11, 27, 7, 23, 15, 31
79 };
80 
81 
82 static int16_t filter_bank[512];
83 
84 static int scale_factor_table[64];
85 #ifdef USE_FLOATS
86 static float scale_factor_inv_table[64];
87 #else
88 static int8_t scale_factor_shift[64];
89 static unsigned short scale_factor_mult[64];
90 #endif
91 static unsigned char scale_diff_table[128];
92 
93 /* total number of bits per allocation group */
94 static unsigned short total_quant_bits[17];
95 
96 /* signal to noise ratio of each quantification step (could be
97  computed from quant_steps[]). The values are dB multiplied by 10
98 */
99 static const unsigned short quant_snr[17] = {
100  70, 110, 160, 208,
101  253, 316, 378, 439,
102  499, 559, 620, 680,
103  740, 800, 861, 920,
104  980
105 };
106 
107 /* fixed psycho acoustic model. Values of SNR taken from the 'toolame'
108  project */
109 static const float fixed_smr[SBLIMIT] = {
110  30, 17, 16, 10, 3, 12, 8, 2.5,
111  5, 5, 6, 6, 5, 6, 10, 6,
112  -4, -10, -21, -30, -42, -55, -68, -75,
113  -75, -75, -75, -75, -91, -107, -110, -108
114 };
115 
116 static const unsigned char nb_scale_factors[4] = { 3, 2, 1, 2 };
117 
118 #endif /* AVCODEC_MPEGAUDIOTAB_H */