path: root/audio_codec/libfaad/drc.c (plain)
blob: 55b4483bc8ddf569e002d06af9d6ea430a5c2f67

1	/*
2	** FAAD2 - Freeware Advanced Audio (AAC) Decoder including SBR decoding
3	** Copyright (C) 2003-2005 M. Bakker, Nero AG, http://www.nero.com
4	**
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.
9	**
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.
14	**
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.
18	**
19	** Any non-GPL usage of this software or parts of this software is strictly
20	** forbidden.
21	**
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"
24	**
25	** Commercial non-GPL licensing of this software is possible.
26	** For more info contact Nero AG through Mpeg4AAClicense@nero.com.
27	**
28	** $Id: drc.c,v 1.28 2007/11/01 12:33:30 menno Exp $
29	**/
30	#include <stdlib.h>
31	#include "common.h"
32	#include "structs.h"
33
34	#include <string.h>
35	#include "syntax.h"
36	#include "drc.h"
37
38	drc_info *drc_init(real_t cut, real_t boost)
39	{
40	drc_info *drc = (drc_info*)faad_malloc(sizeof(drc_info));
41	memset(drc, 0, sizeof(drc_info));
42
43	drc->ctrl1 = cut;
44	drc->ctrl2 = boost;
45
46	drc->num_bands = 1;
47	drc->band_top[0] = 1024 / 4 - 1;
48	drc->dyn_rng_sgn[0] = 1;
49	drc->dyn_rng_ctl[0] = 0;
50
51	return drc;
52	}
53
54	void drc_end(drc_info *drc)
55	{
56	if (drc) {
57	faad_free(drc);
58	}
59	}
60
61	#ifdef FIXED_POINT
62	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)
110	};
111	#endif
112
113	void drc_decode(drc_info *drc, real_t *spec)
114	{
115	uint16_t i, bd, top;
116	#ifdef FIXED_POINT
117	int32_t exp, frac;
118	#else
119	real_t factor, exp;
120	#endif
121	uint16_t bottom = 0;
122
123	if (drc->num_bands == 1) {
124	drc->band_top[0] = 1024 / 4 - 1;
125	}
126
127	for (bd = 0; bd < drc->num_bands; bd++) {
128	top = 4 * (drc->band_top[bd] + 1);
129
130	#ifndef FIXED_POINT
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);
134	} else { /* boost */
135	exp = (drc->ctrl2 * drc->dyn_rng_ctl[bd] - (DRC_REF_LEVEL - drc->prog_ref_level)) / REAL_CONST(24.0);
136	}
137	factor = (real_t)pow(2.0, exp);
138
139	/* Apply gain factor */
140	for (i = bottom; i < top; i++) {
141	spec[i] *= factor;
142	}
143	#else
144	/* Decode DRC gain factor */
145	if (drc->dyn_rng_sgn[bd]) { /* compress */
146	exp = -1 * (drc->dyn_rng_ctl[bd] - (DRC_REF_LEVEL - drc->prog_ref_level)) / 24;
147	frac = -1 * (drc->dyn_rng_ctl[bd] - (DRC_REF_LEVEL - drc->prog_ref_level)) % 24;
148	} else { /* boost */
149	exp = (drc->dyn_rng_ctl[bd] - (DRC_REF_LEVEL - drc->prog_ref_level)) / 24;
150	frac = (drc->dyn_rng_ctl[bd] - (DRC_REF_LEVEL - drc->prog_ref_level)) % 24;
151	}
152
153	/* Apply gain factor */
154	if (exp < 0) {
155	for (i = bottom; i < top; i++) {
156	spec[i] >>= -exp;
157	if (frac) {
158	spec[i] = MUL_R(spec[i], drc_pow2_table[frac + 23]);
159	}
160	}
161	} else {
162	for (i = bottom; i < top; i++) {
163	spec[i] <<= exp;
164	if (frac) {
165	spec[i] = MUL_R(spec[i], drc_pow2_table[frac + 23]);
166	}
167	}
168	}
169	#endif
170
171	bottom = top;
172	}
173	}
174