2 ** FAAD2 - Freeware Advanced Audio (AAC) Decoder including SBR decoding
3 ** Copyright (C) 2003-2005 M. Bakker, Nero AG, http://www.nero.com
5 ** This program is free software; you can redistribute it and/or modify
6 ** it under the terms of the GNU General Public License as published by
7 ** the Free Software Foundation; either version 2 of the License, or
8 ** (at your option) any later version.
10 ** This program is distributed in the hope that it will be useful,
11 ** but WITHOUT ANY WARRANTY; without even the implied warranty of
12 ** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 ** GNU General Public License for more details.
15 ** You should have received a copy of the GNU General Public License
16 ** along with this program; if not, write to the Free Software
17 ** Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
19 ** Any non-GPL usage of this software or parts of this software is strictly
22 ** The "appropriate copyright message" mentioned in section 2c of the GPLv2
23 ** must read: "Code from FAAD2 is copyright (c) Nero AG, www.nero.com"
25 ** Commercial non-GPL licensing of this software is possible.
26 ** For more info contact Nero AG through Mpeg4AAClicense@nero.com.
28 ** $Id: drc.c,v 1.28 2007/11/01 12:33:30 menno Exp $
39 drc_info *drc_init(real_t cut, real_t boost)
41 drc_info *drc = (drc_info*)faad_malloc(sizeof(drc_info));
42 memset(drc, 0, sizeof(drc_info));
48 drc->band_top[0] = 1024/4 - 1;
49 drc->dyn_rng_sgn[0] = 1;
50 drc->dyn_rng_ctl[0] = 0;
55 void drc_end(drc_info *drc)
57 if (drc) faad_free(drc);
61 static real_t drc_pow2_table[] =
63 COEF_CONST(0.5146511183),
64 COEF_CONST(0.5297315472),
65 COEF_CONST(0.5452538663),
66 COEF_CONST(0.5612310242),
67 COEF_CONST(0.5776763484),
68 COEF_CONST(0.5946035575),
69 COEF_CONST(0.6120267717),
70 COEF_CONST(0.6299605249),
71 COEF_CONST(0.6484197773),
72 COEF_CONST(0.6674199271),
73 COEF_CONST(0.6869768237),
74 COEF_CONST(0.7071067812),
75 COEF_CONST(0.7278265914),
76 COEF_CONST(0.7491535384),
77 COEF_CONST(0.7711054127),
78 COEF_CONST(0.7937005260),
79 COEF_CONST(0.8169577266),
80 COEF_CONST(0.8408964153),
81 COEF_CONST(0.8655365610),
82 COEF_CONST(0.8908987181),
83 COEF_CONST(0.9170040432),
84 COEF_CONST(0.9438743127),
85 COEF_CONST(0.9715319412),
86 COEF_CONST(1.0000000000),
87 COEF_CONST(1.0293022366),
88 COEF_CONST(1.0594630944),
89 COEF_CONST(1.0905077327),
90 COEF_CONST(1.1224620483),
91 COEF_CONST(1.1553526969),
92 COEF_CONST(1.1892071150),
93 COEF_CONST(1.2240535433),
94 COEF_CONST(1.2599210499),
95 COEF_CONST(1.2968395547),
96 COEF_CONST(1.3348398542),
97 COEF_CONST(1.3739536475),
98 COEF_CONST(1.4142135624),
99 COEF_CONST(1.4556531828),
100 COEF_CONST(1.4983070769),
101 COEF_CONST(1.5422108254),
102 COEF_CONST(1.5874010520),
103 COEF_CONST(1.6339154532),
104 COEF_CONST(1.6817928305),
105 COEF_CONST(1.7310731220),
106 COEF_CONST(1.7817974363),
107 COEF_CONST(1.8340080864),
108 COEF_CONST(1.8877486254),
109 COEF_CONST(1.9430638823)
113 void drc_decode(drc_info *drc, real_t *spec)
123 if (drc->num_bands == 1)
124 drc->band_top[0] = 1024/4 - 1;
126 for (bd = 0; bd < drc->num_bands; bd++)
128 top = 4 * (drc->band_top[bd] + 1);
131 /* Decode DRC gain factor */
132 if (drc->dyn_rng_sgn[bd]) /* compress */
133 exp = -drc->ctrl1 * (drc->dyn_rng_ctl[bd] - (DRC_REF_LEVEL - drc->prog_ref_level))/REAL_CONST(24.0);
135 exp = drc->ctrl2 * (drc->dyn_rng_ctl[bd] - (DRC_REF_LEVEL - drc->prog_ref_level))/REAL_CONST(24.0);
136 factor = (real_t)pow(2.0, exp);
138 /* Apply gain factor */
139 for (i = bottom; i < top; i++)
142 /* Decode DRC gain factor */
143 if (drc->dyn_rng_sgn[bd]) /* compress */
145 exp = -1 * (drc->dyn_rng_ctl[bd] - (DRC_REF_LEVEL - drc->prog_ref_level))/ 24;
146 frac = -1 * (drc->dyn_rng_ctl[bd] - (DRC_REF_LEVEL - drc->prog_ref_level)) % 24;
148 exp = (drc->dyn_rng_ctl[bd] - (DRC_REF_LEVEL - drc->prog_ref_level))/ 24;
149 frac = (drc->dyn_rng_ctl[bd] - (DRC_REF_LEVEL - drc->prog_ref_level)) % 24;
152 /* Apply gain factor */
155 for (i = bottom; i < top; i++)
159 spec[i] = MUL_R(spec[i],drc_pow2_table[frac+23]);
162 for (i = bottom; i < top; i++)
166 spec[i] = MUL_R(spec[i],drc_pow2_table[frac+23]);