libfaad2/drc.c

   1 /*
   2 ** FAAD2 - Freeware Advanced Audio (AAC) Decoder including SBR decoding
   3 ** Copyright (C) 2003-2004 M. Bakker, Ahead Software 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 ** Commercial non-GPL licensing of this software is possible.
  23 ** For more info contact Ahead Software through Mpeg4AAClicense@nero.com.
  24 **
  25 ** $Id: drc.c,v 1.24 2004/09/04 14:56:28 menno Exp $
  26 **/
  27
  28 #include "common.h"
  29 #include "structs.h"
  30
  31 #include <stdlib.h>
  32 #include <string.h>
  33 #include "syntax.h"
  34 #include "drc.h"
  35
  36 drc_info *drc_init(real_t cut, real_t boost)
  37 {
  38     drc_info *drc = (drc_info*)faad_malloc(sizeof(drc_info));
  39     memset(drc, 0, sizeof(drc_info));
  40
  41     drc->ctrl1 = cut;
  42     drc->ctrl2 = boost;
  43
  44     drc->num_bands = 1;
  45     drc->band_top[0] = 1024/4 - 1;
  46     drc->dyn_rng_sgn[0] = 1;
  47     drc->dyn_rng_ctl[0] = 0;
  48
  49     return drc;
  50 }
  51
  52 void drc_end(drc_info *drc)
  53 {
  54     if (drc) faad_free(drc);
  55 }
  56
  57 #ifdef FIXED_POINT
  58 static real_t drc_pow2_table[] =
  59 {
  60     COEF_CONST(0.5146511183),
  61     COEF_CONST(0.5297315472),
  62     COEF_CONST(0.5452538663),
  63     COEF_CONST(0.5612310242),
  64     COEF_CONST(0.5776763484),
  65     COEF_CONST(0.5946035575),
  66     COEF_CONST(0.6120267717),
  67     COEF_CONST(0.6299605249),
  68     COEF_CONST(0.6484197773),
  69     COEF_CONST(0.6674199271),
  70     COEF_CONST(0.6869768237),
  71     COEF_CONST(0.7071067812),
  72     COEF_CONST(0.7278265914),
  73     COEF_CONST(0.7491535384),
  74     COEF_CONST(0.7711054127),
  75     COEF_CONST(0.7937005260),
  76     COEF_CONST(0.8169577266),
  77     COEF_CONST(0.8408964153),
  78     COEF_CONST(0.8655365610),
  79     COEF_CONST(0.8908987181),
  80     COEF_CONST(0.9170040432),
  81     COEF_CONST(0.9438743127),
  82     COEF_CONST(0.9715319412),
  83     COEF_CONST(1.0000000000),
  84     COEF_CONST(1.0293022366),
  85     COEF_CONST(1.0594630944),
  86     COEF_CONST(1.0905077327),
  87     COEF_CONST(1.1224620483),
  88     COEF_CONST(1.1553526969),
  89     COEF_CONST(1.1892071150),
  90     COEF_CONST(1.2240535433),
  91     COEF_CONST(1.2599210499),
  92     COEF_CONST(1.2968395547),
  93     COEF_CONST(1.3348398542),
  94     COEF_CONST(1.3739536475),
  95     COEF_CONST(1.4142135624),
  96     COEF_CONST(1.4556531828),
  97     COEF_CONST(1.4983070769),
  98     COEF_CONST(1.5422108254),
  99     COEF_CONST(1.5874010520),
 100     COEF_CONST(1.6339154532),
 101     COEF_CONST(1.6817928305),
 102     COEF_CONST(1.7310731220),
 103     COEF_CONST(1.7817974363),
 104     COEF_CONST(1.8340080864),
 105     COEF_CONST(1.8877486254),
 106     COEF_CONST(1.9430638823)
 107 };
 108 #endif
 109
 110 void drc_decode(drc_info *drc, real_t *spec)
 111 {
 112     uint16_t i, bd, top;
 113 #ifdef FIXED_POINT
 114     int32_t exp, frac;
 115 #else
 116     real_t factor, exp;
 117 #endif
 118     uint16_t bottom = 0;
 119
 120     if (drc->num_bands == 1)
 121         drc->band_top[0] = 1024/4 - 1;
 122
 123     for (bd = 0; bd < drc->num_bands; bd++)
 124     {
 125         top = 4 * (drc->band_top[bd] + 1);
 126
 127 #ifndef FIXED_POINT
 128         /* Decode DRC gain factor */
 129         if (drc->dyn_rng_sgn[bd])  /* compress */
 130             exp = -drc->ctrl1 * (drc->dyn_rng_ctl[bd] - (DRC_REF_LEVEL - drc->prog_ref_level))/REAL_CONST(24.0);
 131         else /* boost */
 132             exp = drc->ctrl2 * (drc->dyn_rng_ctl[bd] - (DRC_REF_LEVEL - drc->prog_ref_level))/REAL_CONST(24.0);
 133         factor = (real_t)pow(2.0, exp);
 134
 135         /* Apply gain factor */
 136         for (i = bottom; i < top; i++)
 137             spec[i] *= factor;
 138 #else
 139         /* Decode DRC gain factor */
 140         if (drc->dyn_rng_sgn[bd])  /* compress */
 141         {
 142             exp = -1 * (drc->dyn_rng_ctl[bd] - (DRC_REF_LEVEL - drc->prog_ref_level))/ 24;
 143             frac = -1 * (drc->dyn_rng_ctl[bd] - (DRC_REF_LEVEL - drc->prog_ref_level)) % 24;
 144         } else { /* boost */
 145             exp = (drc->dyn_rng_ctl[bd] - (DRC_REF_LEVEL - drc->prog_ref_level))/ 24;
 146             frac = (drc->dyn_rng_ctl[bd] - (DRC_REF_LEVEL - drc->prog_ref_level)) % 24;
 147         }
 148
 149         /* Apply gain factor */
 150         if (exp < 0)
 151         {
 152             for (i = bottom; i < top; i++)
 153             {
 154                 spec[i] >>= -exp;
 155                 if (frac)
 156                     spec[i] = MUL_R(spec[i],drc_pow2_table[frac+23]);
 157             }
 158         } else {
 159             for (i = bottom; i < top; i++)
 160             {
 161                 spec[i] <<= exp;
 162                 if (frac)
 163                     spec[i] = MUL_R(spec[i],drc_pow2_table[frac+23]);
 164             }
 165         }
 166 #endif
 167
 168         bottom = top;
 169     }
 170 }