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author | arpi <arpi@b3059339-0415-0410-9bf9-f77b7e298cf2> | 2003-08-30 22:30:28 +0000 |
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committer | arpi <arpi@b3059339-0415-0410-9bf9-f77b7e298cf2> | 2003-08-30 22:30:28 +0000 |
commit | 32063c433915b8dddd143a951ad90ae901ac1b38 (patch) | |
tree | 88aaee983b0885b5bb22d870476f7afdaa8a7010 /libfaad2/pns.c | |
parent | 264633eec589baddfdcd79dde08fd7f1f47fba51 (diff) | |
download | mpv-32063c433915b8dddd143a951ad90ae901ac1b38.tar.bz2 mpv-32063c433915b8dddd143a951ad90ae901ac1b38.tar.xz |
libfaad2 v2.0rc1 imported
git-svn-id: svn://svn.mplayerhq.hu/mplayer/trunk@10726 b3059339-0415-0410-9bf9-f77b7e298cf2
Diffstat (limited to 'libfaad2/pns.c')
-rw-r--r-- | libfaad2/pns.c | 234 |
1 files changed, 234 insertions, 0 deletions
diff --git a/libfaad2/pns.c b/libfaad2/pns.c new file mode 100644 index 0000000000..7bdc54c17b --- /dev/null +++ b/libfaad2/pns.c @@ -0,0 +1,234 @@ +/* +** FAAD2 - Freeware Advanced Audio (AAC) Decoder including SBR decoding +** Copyright (C) 2003 M. Bakker, Ahead Software 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. +** +** Commercial non-GPL licensing of this software is possible. +** For more info contact Ahead Software through Mpeg4AAClicense@nero.com. +** +** $Id: pns.c,v 1.21 2003/07/29 08:20:12 menno Exp $ +**/ + +#include "common.h" +#include "structs.h" + +#include "pns.h" + + +#ifdef FIXED_POINT + +#define DIV(A, B) (((int64_t)A << COEF_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 */ +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 <<= (COEF_BITS/2); + + return root; +} + +static real_t pow2_table[] = +{ + COEF_CONST(0.59460355750136), + COEF_CONST(0.70710678118655), + COEF_CONST(0.84089641525371), + 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 + <size> 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) +{ +#ifndef FIXED_POINT + uint16_t i; + real_t energy = 0.0; + + real_t scale = 1.0/(real_t)size * ISQRT_MEAN_NRG; + + for (i = 0; i < size; i++) + { + real_t tmp = scale*(real_t)(int32_t)random_int(); + spec[i] = tmp; + energy += tmp*tmp; + } + + scale = 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++) + { + real_t tmp = ISQRT_MEAN_NRG * (int32_t)random_int(); + tmp = MUL_C_C(COEF_CONST(1)/size, tmp); + + energy += MUL_C_C(tmp,tmp); + + /* convert COEF to REAL */ + spec[i] = (tmp >> -(REAL_BITS-COEF_BITS)); + } + + energy = fp_sqrt(energy); + if (energy > 0) + { + scale = DIV(COEF_CONST(1),energy); + + scale >>= -(REAL_BITS-COEF_BITS); + + exp = scale_factor / 4; + frac = scale_factor % 4; + + if (exp < 0) + scale >>= -exp; + else + scale <<= exp; + + if (frac) + scale = MUL_R_C(scale, pow2_table[frac + 3]); + + for (i = 0; i < size; i++) + { + spec[i] = MUL(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 g, sfb, b; + uint16_t size, offs; + + uint8_t group = 0; + uint16_t nshort = frame_len >> 3; + + 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)) + { + /* 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; + + /* For scalefactor bands coded using PNS the corresponding + predictors are switched to "off". + */ + ics_left->pred.prediction_used[sfb] = 0; + + offs = ics_left->swb_offset[sfb]; + size = ics_left->swb_offset[sfb+1] - offs; + + /* Generate random vector */ + gen_rand_vector(&spec_left[(group*nshort)+offs], + ics_left->scale_factors[g][sfb], size); + } + +/* 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 = ics_right->swb_offset[sfb+1] - 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)*/ { + ics_right->ltp.long_used[sfb] = 0; + ics_right->ltp2.long_used[sfb] = 0; + ics_right->pred.prediction_used[sfb] = 0; + + offs = ics_right->swb_offset[sfb]; + size = ics_right->swb_offset[sfb+1] - offs; + + /* Generate random vector */ + gen_rand_vector(&spec_right[(group*nshort)+offs], + ics_right->scale_factors[g][sfb], size); + } + } + } + } /* sfb */ + group++; + } /* b */ + } /* g */ +} |