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/*
** 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: ic_predict.c,v 1.12 2003/07/29 08:20:12 menno Exp $
**/
#include "common.h"
#include "structs.h"
#ifdef MAIN_DEC
#include "syntax.h"
#include "ic_predict.h"
#include "pns.h"
static void flt_round(real_t *pf)
{
/* more stable version for clever compilers like gcc 3.x */
int32_t flg;
uint32_t tmp, tmp1, tmp2;
tmp = *(uint32_t*)pf;
flg = tmp & (uint32_t)0x00008000;
tmp &= (uint32_t)0xffff0000;
tmp1 = tmp;
/* round 1/2 lsb toward infinity */
if (flg)
{
tmp &= (uint32_t)0xff800000; /* extract exponent and sign */
tmp |= (uint32_t)0x00010000; /* insert 1 lsb */
tmp2 = tmp; /* add 1 lsb and elided one */
tmp &= (uint32_t)0xff800000; /* extract exponent and sign */
*pf = *(real_t*)&tmp1+*(real_t*)&tmp2-*(real_t*)&tmp;/* subtract elided one */
} else {
*pf = *(real_t*)&tmp;
}
}
static void ic_predict(pred_state *state, real_t input, real_t *output, uint8_t pred)
{
real_t dr1, predictedvalue;
real_t e0, e1;
real_t k1, k2;
real_t *r;
real_t *KOR;
real_t *VAR;
r = state->r; /* delay elements */
KOR = state->KOR; /* correlations */
VAR = state->VAR; /* variances */
if (VAR[0] <= 1)
k1 = 0;
else
k1 = KOR[0]/VAR[0]*B;
if (pred)
{
/* only needed for the actual predicted value, k1 is always needed */
if (VAR[1] <= 1)
k2 = 0;
else
k2 = KOR[1]/VAR[1]*B;
predictedvalue = MUL(k1, r[0]) + MUL(k2, r[1]);
flt_round(&predictedvalue);
*output = input + predictedvalue;
} else {
*output = input;
}
/* calculate new state data */
e0 = *output;
e1 = e0 - MUL(k1, r[0]);
dr1 = MUL(k1, e0);
VAR[0] = MUL(ALPHA, VAR[0]) + MUL(REAL_CONST(0.5), (MUL(r[0], r[0]) + MUL(e0, e0)));
KOR[0] = MUL(ALPHA, KOR[0]) + MUL(r[0], e0);
VAR[1] = MUL(ALPHA, VAR[1]) + MUL(REAL_CONST(0.5), (MUL(r[1], r[1]) + MUL(e1, e1)));
KOR[1] = MUL(ALPHA, KOR[1]) + MUL(r[1], e1);
r[1] = MUL(A, (r[0]-dr1));
r[0] = MUL(A, e0);
}
static void reset_pred_state(pred_state *state)
{
state->r[0] = 0;
state->r[1] = 0;
state->KOR[0] = 0;
state->KOR[1] = 0;
state->VAR[0] = REAL_CONST(1.0);
state->VAR[1] = REAL_CONST(1.0);
}
void pns_reset_pred_state(ic_stream *ics, pred_state *state)
{
uint8_t sfb, g, b;
uint16_t i, offs, offs2;
/* prediction only for long blocks */
if (ics->window_sequence == EIGHT_SHORT_SEQUENCE)
return;
for (g = 0; g < ics->num_window_groups; g++)
{
for (b = 0; b < ics->window_group_length[g]; b++)
{
for (sfb = 0; sfb < ics->max_sfb; sfb++)
{
if (is_noise(ics, g, sfb))
{
offs = ics->swb_offset[sfb];
offs2 = ics->swb_offset[sfb+1];
for (i = offs; i < offs2; i++)
reset_pred_state(&state[i]);
}
}
}
}
}
void reset_all_predictors(pred_state *state, uint16_t frame_len)
{
uint16_t i;
for (i = 0; i < frame_len; i++)
reset_pred_state(&state[i]);
}
/* intra channel prediction */
void ic_prediction(ic_stream *ics, real_t *spec, pred_state *state,
uint16_t frame_len)
{
uint8_t sfb;
uint16_t bin;
if (ics->window_sequence == EIGHT_SHORT_SEQUENCE)
{
reset_all_predictors(state, frame_len);
} else {
for (sfb = 0; sfb < ics->pred.limit; sfb++)
{
uint16_t low = ics->swb_offset[sfb];
uint16_t high = ics->swb_offset[sfb+1];
for (bin = low; bin < high; bin++)
{
ic_predict(&state[bin], spec[bin], &spec[bin],
(ics->predictor_data_present &&
ics->pred.prediction_used[sfb]));
}
}
if (ics->predictor_data_present)
{
if (ics->pred.predictor_reset)
{
for (bin = ics->pred.predictor_reset_group_number - 1;
bin < frame_len; bin += 30)
{
reset_pred_state(&state[bin]);
}
}
}
}
}
#endif
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