diff options
Diffstat (limited to 'src/libfaad/pns.c')
| -rw-r--r-- | src/libfaad/pns.c | 69 |
1 files changed, 48 insertions, 21 deletions
diff --git a/src/libfaad/pns.c b/src/libfaad/pns.c index e7a0168e4..911b9cdb0 100644 --- a/src/libfaad/pns.c +++ b/src/libfaad/pns.c @@ -1,6 +1,6 @@ /* -** FAAD - Freeware Advanced Audio Decoder -** Copyright (C) 2002 M. Bakker +** 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 @@ -16,7 +16,13 @@ ** along with this program; if not, write to the Free Software ** Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. ** -** $Id: pns.c,v 1.3 2003/04/12 14:58:47 miguelfreitas Exp $ +** 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 1.4 2003/12/30 02:00:10 miguelfreitas Exp $ **/ #include "common.h" @@ -27,7 +33,7 @@ #ifdef FIXED_POINT -#define DIV(A, B) (((int64_t)A << COEF_BITS)/B) +#define DIV(A, B) (((int64_t)A << REAL_BITS)/B) #define step(shift) \ if ((0x40000000l >> shift) + root <= value) \ @@ -39,6 +45,7 @@ } /* fixed point square root approximation */ +/* !!!! ONLY WORKS FOR EVEN %REAL_BITS% !!!! */ real_t fp_sqrt(real_t value) { real_t root = 0; @@ -51,7 +58,7 @@ real_t fp_sqrt(real_t value) if (root < value) ++root; - root <<= (COEF_BITS/2); + root <<= (REAL_BITS/2); return root; } @@ -73,13 +80,14 @@ static real_t pow2_table[] = 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) +static INLINE void gen_rand_vector(real_t *spec, int16_t scale_factor, uint16_t size, + uint8_t sub) { #ifndef FIXED_POINT uint16_t i; real_t energy = 0.0; - real_t scale = 1.0/(real_t)size * ISQRT_MEAN_NRG; + real_t scale = (real_t)1.0/(real_t)size; for (i = 0; i < size; i++) { @@ -88,7 +96,7 @@ static INLINE void gen_rand_vector(real_t *spec, int16_t scale_factor, uint16_t energy += tmp*tmp; } - scale = 1.0/(real_t)sqrt(energy); + 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++) { @@ -101,36 +109,40 @@ static INLINE void gen_rand_vector(real_t *spec, int16_t scale_factor, uint16_t 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); + /* this can be replaced by a 16 bit random generator!!!! */ + real_t tmp = (int32_t)random_int(); + if (tmp < 0) + tmp = -(tmp & ((1<<(REAL_BITS-1))-1)); + else + tmp = (tmp & ((1<<(REAL_BITS-1))-1)); - energy += MUL_C_C(tmp,tmp); + energy += MUL_R(tmp,tmp); - /* convert COEF to REAL */ - spec[i] = (tmp >> -(REAL_BITS-COEF_BITS)); + spec[i] = tmp; } energy = fp_sqrt(energy); if (energy > 0) { - scale = DIV(COEF_CONST(1),energy); - - scale >>= -(REAL_BITS-COEF_BITS); + scale = DIV(REAL_CONST(1),energy); exp = scale_factor / 4; frac = scale_factor % 4; + /* IMDCT pre-scaling */ + exp -= sub; + if (exp < 0) scale >>= -exp; else scale <<= exp; if (frac) - scale = MUL_R_C(scale, pow2_table[frac + 3]); + scale = MUL_C(scale, pow2_table[frac + 3]); for (i = 0; i < size; i++) { - spec[i] = MUL(spec[i], scale); + spec[i] = MUL_R(spec[i], scale); } } #endif @@ -138,7 +150,7 @@ static INLINE void gen_rand_vector(real_t *spec, int16_t scale_factor, uint16_t 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 channel_pair, uint8_t object_type) { uint8_t g, sfb, b; uint16_t size, offs; @@ -146,6 +158,21 @@ void pns_decode(ic_stream *ics_left, ic_stream *ics_right, 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 */ @@ -173,7 +200,7 @@ void pns_decode(ic_stream *ics_left, ic_stream *ics_right, /* Generate random vector */ gen_rand_vector(&spec_left[(group*nshort)+offs], - ics_left->scale_factors[g][sfb], size); + ics_left->scale_factors[g][sfb], size, sub); } /* From the spec: @@ -217,7 +244,7 @@ void pns_decode(ic_stream *ics_left, ic_stream *ics_right, /* Generate random vector */ gen_rand_vector(&spec_right[(group*nshort)+offs], - ics_right->scale_factors[g][sfb], size); + ics_right->scale_factors[g][sfb], size, sub); } } } |