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/*
** FAAD - Freeware Advanced Audio Decoder
** Copyright (C) 2002 M. Bakker
**
** 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.
**
** $Id: ic_predict.c,v 1.2 2002/12/16 19:00:14 miguelfreitas Exp $
**/
#include "common.h"
#include "structs.h"
#ifdef MAIN_DEC
#include "syntax.h"
#include "ic_predict.h"
#include "pns.h"
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] == 0)
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] == 0)
k2 = 0;
else
k2 = KOR[1]/VAR[1]*B;
predictedvalue = MUL(k1, r[0]) + MUL(k2, r[1]);
*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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