2 ** FAAD2 - Freeware Advanced Audio (AAC) Decoder including SBR decoding
3 ** Copyright (C) 2003-2004 M. Bakker, Ahead Software 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 ** Commercial non-GPL licensing of this software is possible.
23 ** For more info contact Ahead Software through Mpeg4AAClicense@nero.com.
36 /* static variables */
37 static drc_info s_drc_info
;
39 drc_info
*drc_init(real_t cut
, real_t boost
)
41 drc_info
*drc
= &s_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;
56 static real_t drc_pow2_table
[] =
58 COEF_CONST(0.5146511183),
59 COEF_CONST(0.5297315472),
60 COEF_CONST(0.5452538663),
61 COEF_CONST(0.5612310242),
62 COEF_CONST(0.5776763484),
63 COEF_CONST(0.5946035575),
64 COEF_CONST(0.6120267717),
65 COEF_CONST(0.6299605249),
66 COEF_CONST(0.6484197773),
67 COEF_CONST(0.6674199271),
68 COEF_CONST(0.6869768237),
69 COEF_CONST(0.7071067812),
70 COEF_CONST(0.7278265914),
71 COEF_CONST(0.7491535384),
72 COEF_CONST(0.7711054127),
73 COEF_CONST(0.7937005260),
74 COEF_CONST(0.8169577266),
75 COEF_CONST(0.8408964153),
76 COEF_CONST(0.8655365610),
77 COEF_CONST(0.8908987181),
78 COEF_CONST(0.9170040432),
79 COEF_CONST(0.9438743127),
80 COEF_CONST(0.9715319412),
81 COEF_CONST(1.0000000000),
82 COEF_CONST(1.0293022366),
83 COEF_CONST(1.0594630944),
84 COEF_CONST(1.0905077327),
85 COEF_CONST(1.1224620483),
86 COEF_CONST(1.1553526969),
87 COEF_CONST(1.1892071150),
88 COEF_CONST(1.2240535433),
89 COEF_CONST(1.2599210499),
90 COEF_CONST(1.2968395547),
91 COEF_CONST(1.3348398542),
92 COEF_CONST(1.3739536475),
93 COEF_CONST(1.4142135624),
94 COEF_CONST(1.4556531828),
95 COEF_CONST(1.4983070769),
96 COEF_CONST(1.5422108254),
97 COEF_CONST(1.5874010520),
98 COEF_CONST(1.6339154532),
99 COEF_CONST(1.6817928305),
100 COEF_CONST(1.7310731220),
101 COEF_CONST(1.7817974363),
102 COEF_CONST(1.8340080864),
103 COEF_CONST(1.8877486254),
104 COEF_CONST(1.9430638823)
108 void drc_decode(drc_info
*drc
, real_t
*spec
)
118 if (drc
->num_bands
== 1)
119 drc
->band_top
[0] = 1024/4 - 1;
121 for (bd
= 0; bd
< drc
->num_bands
; bd
++)
123 top
= 4 * (drc
->band_top
[bd
] + 1);
126 /* Decode DRC gain factor */
127 if (drc
->dyn_rng_sgn
[bd
]) /* compress */
128 exp
= -drc
->ctrl1
* (drc
->dyn_rng_ctl
[bd
] - (DRC_REF_LEVEL
- drc
->prog_ref_level
))/REAL_CONST(24.0);
130 exp
= drc
->ctrl2
* (drc
->dyn_rng_ctl
[bd
] - (DRC_REF_LEVEL
- drc
->prog_ref_level
))/REAL_CONST(24.0);
131 factor
= (real_t
)pow(2.0, exp
);
133 /* Apply gain factor */
134 for (i
= bottom
; i
< top
; i
++)
137 /* Decode DRC gain factor */
138 if (drc
->dyn_rng_sgn
[bd
]) /* compress */
140 exp
= -1 * (drc
->dyn_rng_ctl
[bd
] - (DRC_REF_LEVEL
- drc
->prog_ref_level
))/ 24;
141 frac
= -1 * (drc
->dyn_rng_ctl
[bd
] - (DRC_REF_LEVEL
- drc
->prog_ref_level
)) % 24;
143 exp
= (drc
->dyn_rng_ctl
[bd
] - (DRC_REF_LEVEL
- drc
->prog_ref_level
))/ 24;
144 frac
= (drc
->dyn_rng_ctl
[bd
] - (DRC_REF_LEVEL
- drc
->prog_ref_level
)) % 24;
147 /* Apply gain factor */
150 for (i
= bottom
; i
< top
; i
++)
154 spec
[i
] = MUL_R(spec
[i
],drc_pow2_table
[frac
+23]);
157 for (i
= bottom
; i
< top
; i
++)
161 spec
[i
] = MUL_R(spec
[i
],drc_pow2_table
[frac
+23]);