From cc2160de5cc05dc3aa77f3a34358e66f6193c8c9 Mon Sep 17 00:00:00 2001 From: Michał Cichoń Date: Tue, 26 Jun 2012 20:35:30 +0200 Subject: Add support for AAC. --- faad2/src/libfaad/pns.c | 271 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 271 insertions(+) create mode 100644 faad2/src/libfaad/pns.c (limited to 'faad2/src/libfaad/pns.c') diff --git a/faad2/src/libfaad/pns.c b/faad2/src/libfaad/pns.c new file mode 100644 index 0000000..fad9800 --- /dev/null +++ b/faad2/src/libfaad/pns.c @@ -0,0 +1,271 @@ +/* +** 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: pns.c,v 1.38 2007/11/01 12:33:32 menno Exp $ +**/ + +#include "common.h" +#include "structs.h" + +#include "pns.h" + + +/* static function declarations */ +static void gen_rand_vector(real_t *spec, int16_t scale_factor, uint16_t size, + uint8_t sub, + /* RNG states */ uint32_t *__r1, uint32_t *__r2); + + +#ifdef FIXED_POINT + +#define DIV(A, B) (((int64_t)A << REAL_BITS)/B) + +#define step(shift) \ + if ((0x40000000l >> shift) + root <= value) \ + { \ + value -= (0x40000000l >> shift) + root; \ + root = (root >> 1) | (0x40000000l >> shift); \ + } else { \ + root = root >> 1; \ + } + +/* fixed point square root approximation */ +/* !!!! ONLY WORKS FOR EVEN %REAL_BITS% !!!! */ +real_t fp_sqrt(real_t value) +{ + real_t root = 0; + + step( 0); step( 2); step( 4); step( 6); + step( 8); step(10); step(12); step(14); + step(16); step(18); step(20); step(22); + step(24); step(26); step(28); step(30); + + if (root < value) + ++root; + + root <<= (REAL_BITS/2); + + return root; +} + +static real_t const pow2_table[] = +{ + COEF_CONST(1.0), + COEF_CONST(1.18920711500272), + COEF_CONST(1.41421356237310), + COEF_CONST(1.68179283050743) +}; +#endif + +/* The function gen_rand_vector(addr, size) generates a vector of length + with signed random values of average energy MEAN_NRG per random + value. A suitable random number generator can be realized using one + multiplication/accumulation per random value. +*/ +static INLINE void gen_rand_vector(real_t *spec, int16_t scale_factor, uint16_t size, + uint8_t sub, + /* RNG states */ uint32_t *__r1, uint32_t *__r2) +{ +#ifndef FIXED_POINT + uint16_t i; + real_t energy = 0.0; + + real_t scale = (real_t)1.0/(real_t)size; + + for (i = 0; i < size; i++) + { + real_t tmp = scale*(real_t)(int32_t)ne_rng(__r1, __r2); + spec[i] = tmp; + energy += tmp*tmp; + } + + scale = (real_t)1.0/(real_t)sqrt(energy); + scale *= (real_t)pow(2.0, 0.25 * scale_factor); + for (i = 0; i < size; i++) + { + spec[i] *= scale; + } +#else + uint16_t i; + real_t energy = 0, scale; + int32_t exp, frac; + + for (i = 0; i < size; i++) + { + /* this can be replaced by a 16 bit random generator!!!! */ + real_t tmp = (int32_t)ne_rng(__r1, __r2); + if (tmp < 0) + tmp = -(tmp & ((1<<(REAL_BITS-1))-1)); + else + tmp = (tmp & ((1<<(REAL_BITS-1))-1)); + + energy += MUL_R(tmp,tmp); + + spec[i] = tmp; + } + + energy = fp_sqrt(energy); + if (energy > 0) + { + scale = DIV(REAL_CONST(1),energy); + + exp = scale_factor >> 2; + frac = scale_factor & 3; + + /* IMDCT pre-scaling */ + exp -= sub; + + if (exp < 0) + scale >>= -exp; + else + scale <<= exp; + + if (frac) + scale = MUL_C(scale, pow2_table[frac]); + + for (i = 0; i < size; i++) + { + spec[i] = MUL_R(spec[i], scale); + } + } +#endif +} + +void pns_decode(ic_stream *ics_left, ic_stream *ics_right, + real_t *spec_left, real_t *spec_right, uint16_t frame_len, + uint8_t channel_pair, uint8_t object_type, + /* RNG states */ uint32_t *__r1, uint32_t *__r2) +{ + uint8_t g, sfb, b; + uint16_t size, offs; + + uint8_t group = 0; + uint16_t nshort = frame_len >> 3; + + uint8_t sub = 0; + +#ifdef FIXED_POINT + /* IMDCT scaling */ + if (object_type == LD) + { + sub = 9 /*9*/; + } else { + if (ics_left->window_sequence == EIGHT_SHORT_SEQUENCE) + sub = 7 /*7*/; + else + sub = 10 /*10*/; + } +#endif + + for (g = 0; g < ics_left->num_window_groups; g++) + { + /* Do perceptual noise substitution decoding */ + for (b = 0; b < ics_left->window_group_length[g]; b++) + { + for (sfb = 0; sfb < ics_left->max_sfb; sfb++) + { + if (is_noise(ics_left, g, sfb)) + { +#ifdef LTP_DEC + /* Simultaneous use of LTP and PNS is not prevented in the + syntax. If both LTP, and PNS are enabled on the same + scalefactor band, PNS takes precedence, and no prediction + is applied to this band. + */ + ics_left->ltp.long_used[sfb] = 0; + ics_left->ltp2.long_used[sfb] = 0; +#endif + +#ifdef MAIN_DEC + /* For scalefactor bands coded using PNS the corresponding + predictors are switched to "off". + */ + ics_left->pred.prediction_used[sfb] = 0; +#endif + + offs = ics_left->swb_offset[sfb]; + size = min(ics_left->swb_offset[sfb+1], ics_left->swb_offset_max) - offs; + + /* Generate random vector */ + gen_rand_vector(&spec_left[(group*nshort)+offs], + ics_left->scale_factors[g][sfb], size, sub, __r1, __r2); + } + +/* From the spec: + If the same scalefactor band and group is coded by perceptual noise + substitution in both channels of a channel pair, the correlation of + the noise signal can be controlled by means of the ms_used field: While + the default noise generation process works independently for each channel + (separate generation of random vectors), the same random vector is used + for both channels if ms_used[] is set for a particular scalefactor band + and group. In this case, no M/S stereo coding is carried out (because M/S + stereo coding and noise substitution coding are mutually exclusive). + If the same scalefactor band and group is coded by perceptual noise + substitution in only one channel of a channel pair the setting of ms_used[] + is not evaluated. +*/ + if (channel_pair) + { + if (is_noise(ics_right, g, sfb)) + { + if (((ics_left->ms_mask_present == 1) && + (ics_left->ms_used[g][sfb])) || + (ics_left->ms_mask_present == 2)) + { + uint16_t c; + + offs = ics_right->swb_offset[sfb]; + size = min(ics_right->swb_offset[sfb+1], ics_right->swb_offset_max) - offs; + + for (c = 0; c < size; c++) + { + spec_right[(group*nshort) + offs + c] = + spec_left[(group*nshort) + offs + c]; + } + } else /*if (ics_left->ms_mask_present == 0)*/ { +#ifdef LTP_DEC + ics_right->ltp.long_used[sfb] = 0; + ics_right->ltp2.long_used[sfb] = 0; +#endif +#ifdef MAIN_DEC + ics_right->pred.prediction_used[sfb] = 0; +#endif + + offs = ics_right->swb_offset[sfb]; + size = min(ics_right->swb_offset[sfb+1], ics_right->swb_offset_max) - offs; + + /* Generate random vector */ + gen_rand_vector(&spec_right[(group*nshort)+offs], + ics_right->scale_factors[g][sfb], size, sub, __r1, __r2); + } + } + } + } /* sfb */ + group++; + } /* b */ + } /* g */ +} -- cgit v1.2.3