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diff --git a/audio_codec/libfaad/is.c b/audio_codec/libfaad/is.c new file mode 100644 index 0000000..dc64cee --- a/dev/null +++ b/audio_codec/libfaad/is.c @@ -0,0 +1,106 @@ +/* +** FAAD2 - Freeware Advanced Audio (AAC) Decoder including SBR decoding +** Copyright (C) 2003-2005 M. Bakker, Nero AG, http://www.nero.com +** +** 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. +** +** Any non-GPL usage of this software or parts of this software is strictly +** forbidden. +** +** The "appropriate copyright message" mentioned in section 2c of the GPLv2 +** must read: "Code from FAAD2 is copyright (c) Nero AG, www.nero.com" +** +** Commercial non-GPL licensing of this software is possible. +** For more info contact Nero AG through Mpeg4AAClicense@nero.com. +** +** $Id: is.c,v 1.28 2007/11/01 12:33:31 menno Exp $ +**/ + +#include "common.h" +#include "structs.h" + +#include "syntax.h" +#include "is.h" + +#ifdef FIXED_POINT +static real_t pow05_table[] = { + COEF_CONST(1.68179283050743), /* 0.5^(-3/4) */ + COEF_CONST(1.41421356237310), /* 0.5^(-2/4) */ + COEF_CONST(1.18920711500272), /* 0.5^(-1/4) */ + COEF_CONST(1.0), /* 0.5^( 0/4) */ + COEF_CONST(0.84089641525371), /* 0.5^(+1/4) */ + COEF_CONST(0.70710678118655), /* 0.5^(+2/4) */ + COEF_CONST(0.59460355750136) /* 0.5^(+3/4) */ +}; +#endif + +void is_decode(ic_stream *ics, ic_stream *icsr, real_t *l_spec, real_t *r_spec, + uint16_t frame_len) +{ + uint8_t g, sfb, b; + uint16_t i; +#ifndef FIXED_POINT + real_t scale; +#else + int32_t exp, frac; +#endif + + uint16_t nshort = frame_len / 8; + uint8_t group = 0; + + for (g = 0; g < icsr->num_window_groups; g++) { + /* Do intensity stereo decoding */ + for (b = 0; b < icsr->window_group_length[g]; b++) { + for (sfb = 0; sfb < icsr->max_sfb; sfb++) { + if (is_intensity(icsr, g, sfb)) { +#ifdef MAIN_DEC + /* For scalefactor bands coded in intensity stereo the + corresponding predictors in the right channel are + switched to "off". + */ + ics->pred.prediction_used[sfb] = 0; + icsr->pred.prediction_used[sfb] = 0; +#endif + +#ifndef FIXED_POINT + scale = (real_t)pow(0.5, (0.25 * icsr->scale_factors[g][sfb])); +#else + exp = icsr->scale_factors[g][sfb] >> 2; + frac = icsr->scale_factors[g][sfb] & 3; +#endif + + /* Scale from left to right channel, + do not touch left channel */ + for (i = icsr->swb_offset[sfb]; i < min(icsr->swb_offset[sfb + 1], ics->swb_offset_max); i++) { +#ifndef FIXED_POINT + r_spec[(group * nshort) + i] = MUL_R(l_spec[(group * nshort) + i], scale); +#else + if (exp < 0) { + r_spec[(group * nshort) + i] = l_spec[(group * nshort) + i] << -exp; + } else { + r_spec[(group * nshort) + i] = l_spec[(group * nshort) + i] >> exp; + } + r_spec[(group * nshort) + i] = MUL_C(r_spec[(group * nshort) + i], pow05_table[frac + 3]); +#endif + if (is_intensity(icsr, g, sfb) != invert_intensity(ics, g, sfb)) { + r_spec[(group * nshort) + i] = -r_spec[(group * nshort) + i]; + } + } + } + } + group++; + } + } +} |