2 * mpeg audio layer 2 tables. Most of them come from the mpeg audio
5 * Copyright (c) 2000, 2001 Fabrice Bellard.
7 * The licence of this code is contained in file LICENCE found in the
11 #define SQRT2 1.41421356237309514547
13 static const int costab32[30] = {
14 FIX(0.54119610014619701222),
15 FIX(1.3065629648763763537),
17 FIX(0.50979557910415917998),
18 FIX(2.5629154477415054814),
19 FIX(0.89997622313641556513),
20 FIX(0.60134488693504528634),
22 FIX(0.5024192861881556782),
23 FIX(5.1011486186891552563),
24 FIX(0.78815462345125020249),
25 FIX(0.64682178335999007679),
26 FIX(0.56694403481635768927),
27 FIX(1.0606776859903470633),
28 FIX(1.7224470982383341955),
29 FIX(0.52249861493968885462),
31 FIX(10.19000812354803287),
32 FIX(0.674808341455005678),
33 FIX(1.1694399334328846596),
34 FIX(0.53104259108978413284),
35 FIX(2.0577810099534108446),
36 FIX(0.58293496820613388554),
37 FIX(0.83934964541552681272),
38 FIX(0.50547095989754364798),
39 FIX(3.4076084184687189804),
40 FIX(0.62250412303566482475),
41 FIX(0.97256823786196078263),
42 FIX(0.51544730992262455249),
43 FIX(1.4841646163141661852),
44 FIX(0.5531038960344445421),
45 FIX(0.74453627100229857749),
46 FIX(0.5006029982351962726),
49 static const int bitinv32[32] = {
50 0, 16, 8, 24, 4, 20, 12, 28,
51 2, 18, 10, 26, 6, 22, 14, 30,
52 1, 17, 9, 25, 5, 21, 13, 29,
53 3, 19, 11, 27, 7, 23, 15, 31
57 static INT16 filter_bank[512];
59 static int scale_factor_table[64];
61 static float scale_factor_inv_table[64];
63 static INT8 scale_factor_shift[64];
64 static unsigned short scale_factor_mult[64];
66 static unsigned char scale_diff_table[128];
68 /* total number of bits per allocation group */
69 static unsigned short total_quant_bits[17];
71 /* signal to noise ratio of each quantification step (could be
72 computed from quant_steps[]). The values are dB multiplied by 10
74 static unsigned short quant_snr[17] = {
82 /* fixed psycho acoustic model. Values of SNR taken from the 'toolame'
84 static const float fixed_smr[SBLIMIT] = {
85 30, 17, 16, 10, 3, 12, 8, 2.5,
86 5, 5, 6, 6, 5, 6, 10, 6,
87 -4, -10, -21, -30, -42, -55, -68, -75,
88 -75, -75, -75, -75, -91, -107, -110, -108
91 static const unsigned char nb_scale_factors[4] = { 3, 2, 1, 2 };