ref: dd018ff492773b6be8bd786a026cbb1d5ca9c24e
dir: /libfaad/ic_predict.c/
/*
** FAAD2 - Freeware Advanced Audio (AAC) Decoder including SBR decoding
** Copyright (C) 2003-2004 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 1.23 2004/09/04 14:56:28 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(float32_t *pf)
{
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 = *(float32_t*)&tmp1 + *(float32_t*)&tmp2 - *(float32_t*)&tmp;
} else {
*pf = *(float32_t*)&tmp;
}
}
static int16_t quant_pred(float32_t x)
{
int16_t q;
uint32_t *tmp = (uint32_t*)&x;
q = (int16_t)(*tmp>>16);
return q;
}
static float32_t inv_quant_pred(int16_t q)
{
float32_t x;
uint32_t *tmp = (uint32_t*)&x;
*tmp = ((uint32_t)q)<<16;
return x;
}
static void ic_predict(pred_state *state, real_t input, real_t *output, uint8_t pred)
{
uint16_t tmp;
int16_t i, j;
real_t dr1, predictedvalue;
real_t e0, e1;
real_t k1, k2;
real_t r[2];
real_t COR[2];
real_t VAR[2];
r[0] = inv_quant_pred(state->r[0]);
r[1] = inv_quant_pred(state->r[1]);
COR[0] = inv_quant_pred(state->COR[0]);
COR[1] = inv_quant_pred(state->COR[1]);
VAR[0] = inv_quant_pred(state->VAR[0]);
VAR[1] = inv_quant_pred(state->VAR[1]);
#if 1
tmp = state->VAR[0];
j = (tmp >> 7);
i = tmp & 0x7f;
if (j >= 128)
{
j -= 128;
k1 = COR[0] * exp_table[j] * mnt_table[i];
} else {
k1 = REAL_CONST(0);
}
#else
{
#define B 0.953125
real_t c = COR[0];
real_t v = VAR[0];
real_t tmp;
if (c == 0 || v <= 1)
{
k1 = 0;
} else {
tmp = B / v;
flt_round(&tmp);
k1 = c * tmp;
}
}
#endif
if (pred)
{
#if 1
tmp = state->VAR[1];
j = (tmp >> 7);
i = tmp & 0x7f;
if (j >= 128)
{
j -= 128;
k2 = COR[1] * exp_table[j] * mnt_table[i];
} else {
k2 = REAL_CONST(0);
}
#else
#define B 0.953125
real_t c = COR[1];
real_t v = VAR[1];
real_t tmp;
if (c == 0 || v <= 1)
{
k2 = 0;
} else {
tmp = B / v;
flt_round(&tmp);
k2 = c * tmp;
}
#endif
predictedvalue = k1*r[0] + k2*r[1];
flt_round(&predictedvalue);
*output = input + predictedvalue;
}
/* calculate new state data */
e0 = *output;
e1 = e0 - k1*r[0];
dr1 = k1*e0;
VAR[0] = ALPHA*VAR[0] + 0.5f * (r[0]*r[0] + e0*e0);
COR[0] = ALPHA*COR[0] + r[0]*e0;
VAR[1] = ALPHA*VAR[1] + 0.5f * (r[1]*r[1] + e1*e1);
COR[1] = ALPHA*COR[1] + r[1]*e1;
r[1] = A * (r[0]-dr1);
r[0] = A * e0;
state->r[0] = quant_pred(r[0]);
state->r[1] = quant_pred(r[1]);
state->COR[0] = quant_pred(COR[0]);
state->COR[1] = quant_pred(COR[1]);
state->VAR[0] = quant_pred(VAR[0]);
state->VAR[1] = quant_pred(VAR[1]);
}
static void reset_pred_state(pred_state *state)
{
state->r[0] = 0;
state->r[1] = 0;
state->COR[0] = 0;
state->COR[1] = 0;
state->VAR[0] = 0x3F80;
state->VAR[1] = 0x3F80;
}
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 sf_index)
{
uint8_t sfb;
uint16_t bin;
if (ics->window_sequence == EIGHT_SHORT_SEQUENCE)
{
reset_all_predictors(state, frame_len);
} else {
for (sfb = 0; sfb < max_pred_sfb(sf_index); 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