ref: e98a69b9db88ef00994bbc7a95add426a36adcf6
dir: /libfaad/drc.c/
/* ** FAAD - Freeware Advanced Audio Decoder ** Copyright (C) 2002 M. Bakker ** ** This program is free software; you can redistribute it and/or modify ** it under the terms of the GNU General Public License as published by ** the Free Software Foundation; either version 2 of the License, or ** (at your option) any later version. ** ** This program is distributed in the hope that it will be useful, ** but WITHOUT ANY WARRANTY; without even the implied warranty of ** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the ** GNU General Public License for more details. ** ** You should have received a copy of the GNU General Public License ** along with this program; if not, write to the Free Software ** Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. ** ** $Id: drc.c,v 1.12 2002/11/28 18:48:30 menno Exp $ **/ #include "common.h" #include "structs.h" #include <stdlib.h> #include <string.h> #include "syntax.h" #include "drc.h" drc_info *drc_init(real_t cut, real_t boost) { drc_info *drc = (drc_info*)malloc(sizeof(drc_info)); memset(drc, 0, sizeof(drc_info)); drc->ctrl1 = cut; drc->ctrl2 = boost; drc->num_bands = 1; drc->band_top[0] = 1024/4 - 1; drc->dyn_rng_sgn[0] = 1; drc->dyn_rng_ctl[0] = 0; return drc; } void drc_end(drc_info *drc) { if (drc) free(drc); } #ifdef FIXED_POINT static real_t drc_pow2_table[] = { COEF_CONST(0.5146511183), COEF_CONST(0.5297315472), COEF_CONST(0.5452538663), COEF_CONST(0.5612310242), COEF_CONST(0.5776763484), COEF_CONST(0.5946035575), COEF_CONST(0.6120267717), COEF_CONST(0.6299605249), COEF_CONST(0.6484197773), COEF_CONST(0.6674199271), COEF_CONST(0.6869768237), COEF_CONST(0.7071067812), COEF_CONST(0.7278265914), COEF_CONST(0.7491535384), COEF_CONST(0.7711054127), COEF_CONST(0.7937005260), COEF_CONST(0.8169577266), COEF_CONST(0.8408964153), COEF_CONST(0.8655365610), COEF_CONST(0.8908987181), COEF_CONST(0.9170040432), COEF_CONST(0.9438743127), COEF_CONST(0.9715319412), COEF_CONST(1.0000000000), COEF_CONST(1.0293022366), COEF_CONST(1.0594630944), COEF_CONST(1.0905077327), COEF_CONST(1.1224620483), COEF_CONST(1.1553526969), COEF_CONST(1.1892071150), COEF_CONST(1.2240535433), COEF_CONST(1.2599210499), COEF_CONST(1.2968395547), COEF_CONST(1.3348398542), COEF_CONST(1.3739536475), COEF_CONST(1.4142135624), COEF_CONST(1.4556531828), COEF_CONST(1.4983070769), COEF_CONST(1.5422108254), COEF_CONST(1.5874010520), COEF_CONST(1.6339154532), COEF_CONST(1.6817928305), COEF_CONST(1.7310731220), COEF_CONST(1.7817974363), COEF_CONST(1.8340080864), COEF_CONST(1.8877486254), COEF_CONST(1.9430638823) }; #endif void drc_decode(drc_info *drc, real_t *spec) { uint16_t i, bd, top; #ifdef FIXED_POINT int32_t exp, frac; #else real_t factor, exp; #endif uint16_t bottom = 0; if (drc->num_bands == 1) drc->band_top[0] = 1024/4 - 1; for (bd = 0; bd < drc->num_bands; bd++) { top = 4 * (drc->band_top[bd] + 1); #ifndef FIXED_POINT /* Decode DRC gain factor */ if (drc->dyn_rng_sgn[bd]) /* compress */ exp = -drc->ctrl1 * (drc->dyn_rng_ctl[bd] - (DRC_REF_LEVEL - drc->prog_ref_level))/24.0; else /* boost */ exp = drc->ctrl2 * (drc->dyn_rng_ctl[bd] - (DRC_REF_LEVEL - drc->prog_ref_level))/24.0; factor = (real_t)pow(2.0, exp); /* Apply gain factor */ for (i = bottom; i < top; i++) spec[i] *= factor; #else /* Decode DRC gain factor */ if (drc->dyn_rng_sgn[bd]) /* compress */ { exp = -1 * (drc->dyn_rng_ctl[bd] - (DRC_REF_LEVEL - drc->prog_ref_level))/ 24; frac = -1 * (drc->dyn_rng_ctl[bd] - (DRC_REF_LEVEL - drc->prog_ref_level)) % 24; } else { /* boost */ exp = (drc->dyn_rng_ctl[bd] - (DRC_REF_LEVEL - drc->prog_ref_level))/ 24; frac = (drc->dyn_rng_ctl[bd] - (DRC_REF_LEVEL - drc->prog_ref_level)) % 24; } /* Apply gain factor */ if (exp < 0) { for (i = bottom; i < top; i++) { spec[i] >>= -exp; if (frac) spec[i] = MUL(spec[i],drc_pow2_table[frac+23]); } } else { for (i = bottom; i < top; i++) { spec[i] <<= exp; if (frac) spec[i] = MUL(spec[i],drc_pow2_table[frac+23]); } } #endif bottom = top; } }