ref: 064740662b4b78775c62f610a84dc17969a1aabf
dir: /libfaad/sbr_hfgen.c/
/*
** 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: sbr_hfgen.c,v 1.9 2003/11/02 20:24:05 menno Exp $
**/
/* High Frequency generation */
#include "common.h"
#include "structs.h"
#ifdef SBR_DEC
#include "sbr_syntax.h"
#include "sbr_hfgen.h"
#include "sbr_fbt.h"
void hf_generation(sbr_info *sbr, const qmf_t Xlow[MAX_NTSRHFG][32],
qmf_t Xhigh[MAX_NTSRHFG][64]
#ifdef SBR_LOW_POWER
,real_t *deg
#endif
,uint8_t ch)
{
uint8_t l, i, x;
uint8_t offset, first, last;
complex_t alpha_0[64], alpha_1[64];
#ifdef SBR_LOW_POWER
real_t rxx[64];
#endif
#ifdef DRM
if (sbr->Is_DRM_SBR)
{
offset = sbr->tHFGen;
first = 0;
last = sbr->numTimeSlotsRate;
} else
#endif
{
offset = sbr->tHFAdj;
first = sbr->t_E[ch][0];
last = sbr->t_E[ch][sbr->L_E[ch]];
}
calc_chirp_factors(sbr, ch);
if ((ch == 0) && (sbr->Reset))
patch_construction(sbr);
/* calculate the prediction coefficients */
calc_prediction_coef(sbr, Xlow, alpha_0, alpha_1
#ifdef SBR_LOW_POWER
, rxx
#endif
);
#ifdef SBR_LOW_POWER
calc_aliasing_degree(sbr, rxx, deg);
#endif
/* actual HF generation */
for (i = 0; i < sbr->noPatches; i++)
{
for (x = 0; x < sbr->patchNoSubbands[i]; x++)
{
complex_t a0, a1;
real_t bw, bw2;
uint8_t q, p, k, g;
/* find the low and high band for patching */
k = sbr->kx + x;
for (q = 0; q < i; q++)
{
k += sbr->patchNoSubbands[q];
}
p = sbr->patchStartSubband[i] + x;
#ifdef SBR_LOW_POWER
if (x != 0 /*x < sbr->patchNoSubbands[i]-1*/)
deg[k] = deg[p];
else
deg[k] = 0;
#endif
g = sbr->table_map_k_to_g[k];
bw = sbr->bwArray[ch][g];
bw2 = MUL_C_C(bw, bw);
/* do the patching */
/* with or without filtering */
if (bw2 > 0)
{
RE(a0) = MUL_R_C(RE(alpha_0[p]), bw);
RE(a1) = MUL_R_C(RE(alpha_1[p]), bw2);
#ifndef SBR_LOW_POWER
IM(a0) = MUL_R_C(IM(alpha_0[p]), bw);
IM(a1) = MUL_R_C(IM(alpha_1[p]), bw2);
#endif
for (l = first; l < last; l++)
{
QMF_RE(Xhigh[l + offset][k]) = QMF_RE(Xlow[l + offset][p]);
#ifndef SBR_LOW_POWER
QMF_IM(Xhigh[l + offset][k]) = QMF_IM(Xlow[l + offset][p]);
#endif
#ifdef SBR_LOW_POWER
QMF_RE(Xhigh[l + offset][k]) += (
MUL(RE(a0), QMF_RE(Xlow[l - 1 + offset][p])) +
MUL(RE(a1), QMF_RE(Xlow[l - 2 + offset][p])));
#else
QMF_RE(Xhigh[l + offset][k]) += (
RE(a0) * QMF_RE(Xlow[l - 1 + offset][p]) -
IM(a0) * QMF_IM(Xlow[l - 1 + offset][p]) +
RE(a1) * QMF_RE(Xlow[l - 2 + offset][p]) -
IM(a1) * QMF_IM(Xlow[l - 2 + offset][p]));
QMF_IM(Xhigh[l + offset][k]) += (
IM(a0) * QMF_RE(Xlow[l - 1 + offset][p]) +
RE(a0) * QMF_IM(Xlow[l - 1 + offset][p]) +
IM(a1) * QMF_RE(Xlow[l - 2 + offset][p]) +
RE(a1) * QMF_IM(Xlow[l - 2 + offset][p]));
#endif
}
} else {
for (l = first; l < last; l++)
{
QMF_RE(Xhigh[l + offset][k]) = QMF_RE(Xlow[l + offset][p]);
#ifndef SBR_LOW_POWER
QMF_IM(Xhigh[l + offset][k]) = QMF_IM(Xlow[l + offset][p]);
#endif
}
}
}
}
if (sbr->Reset)
{
limiter_frequency_table(sbr);
}
}
typedef struct
{
complex_t r01;
complex_t r02;
complex_t r11;
complex_t r12;
complex_t r22;
real_t det;
} acorr_coef;
#define SBR_ABS(A) ((A) < 0) ? -(A) : (A)
#ifdef SBR_LOW_POWER
static void auto_correlation(sbr_info *sbr, acorr_coef *ac,
const qmf_t buffer[MAX_NTSRHFG][32],
uint8_t bd, uint8_t len)
{
real_t r01 = 0, r02 = 0, r11 = 0;
int8_t j;
uint8_t offset;
const real_t rel = 1 / (1 + 1e-6f);
#ifdef DRM
if (sbr->Is_DRM_SBR)
offset = sbr->tHFGen;
else
#endif
{
offset = sbr->tHFAdj;
}
for (j = offset; j < len + offset; j++)
{
RE(ac->r01) += QMF_RE(buffer[j][bd]) * QMF_RE(buffer[j-1][bd]);
RE(ac->r02) += QMF_RE(buffer[j][bd]) * QMF_RE(buffer[j-2][bd]);
RE(ac->r11) += QMF_RE(buffer[j-1][bd]) * QMF_RE(buffer[j-1][bd]);
}
RE(ac->r12) = r01 -
QMF_RE(buffer[len+offset-1][bd]) * QMF_RE(buffer[len+offset-2][bd]) +
QMF_RE(buffer[offset-1][bd]) * QMF_RE(buffer[offset-2][bd]);
RE(ac->r22) = r11 -
QMF_RE(buffer[len+offset-2][bd]) * QMF_RE(buffer[len+offset-2][bd]) +
QMF_RE(buffer[offset-2][bd]) * QMF_RE(buffer[offset-2][bd]);
RE(ac->r01) = r01;
RE(ac->r02) = r02;
RE(ac->r11) = r11;
ac->det = MUL(RE(ac->r11), RE(ac->r22)) - MUL_R_C(MUL(RE(ac->r12), RE(ac->r12)), rel);
}
#else
static void auto_correlation(sbr_info *sbr, acorr_coef *ac, const qmf_t buffer[MAX_NTSRHFG][32],
uint8_t bd, uint8_t len)
{
real_t r01r = 0, r01i = 0, r02r = 0, r02i = 0, r11r = 0;
const real_t rel = 1 / (1 + 1e-6f);
int8_t j;
uint8_t offset;
#ifdef DRM
if (sbr->Is_DRM_SBR)
offset = sbr->tHFGen;
else
#endif
{
offset = sbr->tHFAdj;
}
for (j = offset; j < len + offset; j++)
{
r01r += QMF_RE(buffer[j][bd]) * QMF_RE(buffer[j-1][bd]) +
QMF_IM(buffer[j][bd]) * QMF_IM(buffer[j-1][bd]);
r01i += QMF_IM(buffer[j][bd]) * QMF_RE(buffer[j-1][bd]) -
QMF_RE(buffer[j][bd]) * QMF_IM(buffer[j-1][bd]);
r02r += QMF_RE(buffer[j][bd]) * QMF_RE(buffer[j-2][bd]) +
QMF_IM(buffer[j][bd]) * QMF_IM(buffer[j-2][bd]);
r02i += QMF_IM(buffer[j][bd]) * QMF_RE(buffer[j-2][bd]) -
QMF_RE(buffer[j][bd]) * QMF_IM(buffer[j-2][bd]);
r11r += QMF_RE(buffer[j-1][bd]) * QMF_RE(buffer[j-1][bd]) +
QMF_IM(buffer[j-1][bd]) * QMF_IM(buffer[j-1][bd]);
}
RE(ac->r01) = r01r;
IM(ac->r01) = r01i;
RE(ac->r02) = r02r;
IM(ac->r02) = r02i;
RE(ac->r11) = r11r;
RE(ac->r12) = r01r -
(QMF_RE(buffer[len+offset-1][bd]) * QMF_RE(buffer[len+offset-2][bd]) + QMF_IM(buffer[len+offset-1][bd]) * QMF_IM(buffer[len+offset-2][bd])) +
(QMF_RE(buffer[offset-1][bd]) * QMF_RE(buffer[offset-2][bd]) + QMF_IM(buffer[offset-1][bd]) * QMF_IM(buffer[offset-2][bd]));
IM(ac->r12) = r01i -
(QMF_IM(buffer[len+offset-1][bd]) * QMF_RE(buffer[len+offset-2][bd]) - QMF_RE(buffer[len+offset-1][bd]) * QMF_IM(buffer[len+offset-2][bd])) +
(QMF_IM(buffer[offset-1][bd]) * QMF_RE(buffer[offset-2][bd]) - QMF_RE(buffer[offset-1][bd]) * QMF_IM(buffer[offset-2][bd]));
RE(ac->r22) = r11r -
(QMF_RE(buffer[len+offset-2][bd]) * QMF_RE(buffer[len+offset-2][bd]) + QMF_IM(buffer[len+offset-2][bd]) * QMF_IM(buffer[len+offset-2][bd])) +
(QMF_RE(buffer[offset-2][bd]) * QMF_RE(buffer[offset-2][bd]) + QMF_IM(buffer[offset-2][bd]) * QMF_IM(buffer[offset-2][bd]));
ac->det = RE(ac->r11) * RE(ac->r22) - rel * (RE(ac->r12) * RE(ac->r12) + IM(ac->r12) * IM(ac->r12));
}
#endif
/* calculate linear prediction coefficients using the covariance method */
static void calc_prediction_coef(sbr_info *sbr, const qmf_t Xlow[MAX_NTSRHFG][32],
complex_t *alpha_0, complex_t *alpha_1
#ifdef SBR_LOW_POWER
, real_t *rxx
#endif
)
{
uint8_t k;
real_t tmp;
acorr_coef ac;
for (k = 1; k < sbr->f_master[0]; k++)
{
#ifdef DRM
if (sbr->Is_DRM_SBR)
auto_correlation(sbr, &ac, Xlow, k, 30);
else
#endif
{
auto_correlation(sbr, &ac, Xlow, k, 38);
}
#ifdef SBR_LOW_POWER
if (ac.det == 0)
{
RE(alpha_1[k]) = 0;
} else {
tmp = MUL(RE(ac.r01), RE(ac.r12)) - MUL(RE(ac.r02), RE(ac.r11));
RE(alpha_1[k]) = SBR_DIV(tmp, ac.det);
}
if (RE(ac.r11) == 0)
{
RE(alpha_0[k]) = 0;
} else {
tmp = RE(ac.r01) + MUL(RE(alpha_1[k]), RE(ac.r12));
RE(alpha_0[k]) = -SBR_DIV(tmp, RE(ac.r11));
}
if ((RE(alpha_0[k]) >= REAL_CONST(4)) || (RE(alpha_1[k]) >= REAL_CONST(4)))
{
RE(alpha_0[k]) = REAL_CONST(0);
RE(alpha_1[k]) = REAL_CONST(0);
}
/* reflection coefficient */
if (RE(ac.r11) == REAL_CONST(0.0))
{
rxx[k] = REAL_CONST(0.0);
} else {
rxx[k] = -SBR_DIV(RE(ac.r01), RE(ac.r11));
if (rxx[k] > REAL_CONST(1.0)) rxx[k] = REAL_CONST(1.0);
if (rxx[k] < REAL_CONST(-1.0)) rxx[k] = REAL_CONST(-1.0);
}
#else
if (ac.det == 0)
{
RE(alpha_1[k]) = 0;
IM(alpha_1[k]) = 0;
} else {
tmp = REAL_CONST(1.0) / ac.det;
RE(alpha_1[k]) = (RE(ac.r01) * RE(ac.r12) - IM(ac.r01) * IM(ac.r12) - RE(ac.r02) * RE(ac.r11)) * tmp;
IM(alpha_1[k]) = (IM(ac.r01) * RE(ac.r12) + RE(ac.r01) * IM(ac.r12) - IM(ac.r02) * RE(ac.r11)) * tmp;
}
if (RE(ac.r11) == 0)
{
RE(alpha_0[k]) = 0;
IM(alpha_0[k]) = 0;
} else {
tmp = 1.0f / RE(ac.r11);
RE(alpha_0[k]) = -(RE(ac.r01) + RE(alpha_1[k]) * RE(ac.r12) + IM(alpha_1[k]) * IM(ac.r12)) * tmp;
IM(alpha_0[k]) = -(IM(ac.r01) + IM(alpha_1[k]) * RE(ac.r12) - RE(alpha_1[k]) * IM(ac.r12)) * tmp;
}
if ((RE(alpha_0[k])*RE(alpha_0[k]) + IM(alpha_0[k])*IM(alpha_0[k]) >= 16) ||
(RE(alpha_1[k])*RE(alpha_1[k]) + IM(alpha_1[k])*IM(alpha_1[k]) >= 16))
{
RE(alpha_0[k]) = 0;
IM(alpha_0[k]) = 0;
RE(alpha_1[k]) = 0;
IM(alpha_1[k]) = 0;
}
#endif
}
}
#ifdef SBR_LOW_POWER
static void calc_aliasing_degree(sbr_info *sbr, real_t *rxx, real_t *deg)
{
uint8_t k;
rxx[0] = REAL_CONST(0.0);
deg[1] = REAL_CONST(0.0);
for (k = 2; k < sbr->k0; k++)
{
deg[k] = 0.0;
if ((k % 2 == 0) && (rxx[k] < REAL_CONST(0.0)))
{
if (rxx[k-1] < 0.0)
{
deg[k] = REAL_CONST(1.0);
if (rxx[k-2] > REAL_CONST(0.0))
{
deg[k-1] = REAL_CONST(1.0) - MUL(rxx[k-1], rxx[k-1]);
}
} else if (rxx[k-2] > REAL_CONST(0.0)) {
deg[k] = REAL_CONST(1.0) - MUL(rxx[k-1], rxx[k-1]);
}
}
if ((k % 2 == 1) && (rxx[k] > REAL_CONST(0.0)))
{
if (rxx[k-1] > REAL_CONST(0.0))
{
deg[k] = REAL_CONST(1.0);
if (rxx[k-2] < REAL_CONST(0.0))
{
deg[k-1] = REAL_CONST(1.0) - MUL(rxx[k-1], rxx[k-1]);
}
} else if (rxx[k-2] < REAL_CONST(0.0)) {
deg[k] = REAL_CONST(1.0) - MUL(rxx[k-1], rxx[k-1]);
}
}
}
}
#endif
static real_t mapNewBw(uint8_t invf_mode, uint8_t invf_mode_prev)
{
switch (invf_mode)
{
case 1: /* LOW */
if (invf_mode_prev == 0) /* NONE */
return COEF_CONST(0.6);
else
return COEF_CONST(0.75);
case 2: /* MID */
return COEF_CONST(0.9);
case 3: /* HIGH */
return COEF_CONST(0.98);
default: /* NONE */
if (invf_mode_prev == 1) /* LOW */
return COEF_CONST(0.6);
else
return COEF_CONST(0.0);
}
}
static void calc_chirp_factors(sbr_info *sbr, uint8_t ch)
{
uint8_t i;
for (i = 0; i < sbr->N_Q; i++)
{
sbr->bwArray[ch][i] = mapNewBw(sbr->bs_invf_mode[ch][i], sbr->bs_invf_mode_prev[ch][i]);
if (sbr->bwArray[ch][i] < sbr->bwArray_prev[ch][i])
sbr->bwArray[ch][i] = MUL_C_C(COEF_CONST(0.75), sbr->bwArray[ch][i]) + MUL_C_C(COEF_CONST(0.25), sbr->bwArray_prev[ch][i]);
else
sbr->bwArray[ch][i] = MUL_C_C(COEF_CONST(0.90625), sbr->bwArray[ch][i]) + MUL_C_C(COEF_CONST(0.09375), sbr->bwArray_prev[ch][i]);
if (sbr->bwArray[ch][i] < COEF_CONST(0.015625))
sbr->bwArray[ch][i] = COEF_CONST(0.0);
if (sbr->bwArray[ch][i] >= COEF_CONST(0.99609375))
sbr->bwArray[ch][i] = COEF_CONST(0.99609375);
sbr->bwArray_prev[ch][i] = sbr->bwArray[ch][i];
sbr->bs_invf_mode_prev[ch][i] = sbr->bs_invf_mode[ch][i];
}
}
static void patch_construction(sbr_info *sbr)
{
uint8_t i, k;
uint8_t odd, sb;
uint8_t msb = sbr->k0;
uint8_t usb = sbr->kx;
uint8_t goalSb = (uint8_t)(2.048e6/sbr->sample_rate + 0.5);
sbr->noPatches = 0;
if (goalSb < (sbr->kx + sbr->M))
{
for (i = 0, k = 0; sbr->f_master[i] < goalSb; i++)
k = i+1;
} else {
k = sbr->N_master;
}
do
{
uint8_t j = k + 1;
do
{
j--;
sb = sbr->f_master[j];
odd = (sb - 2 + sbr->k0) % 2;
} while (sb > (sbr->k0 - 1 + msb - odd));
sbr->patchNoSubbands[sbr->noPatches] = max(sb - usb, 0);
sbr->patchStartSubband[sbr->noPatches] = sbr->k0 - odd -
sbr->patchNoSubbands[sbr->noPatches];
if (sbr->patchNoSubbands[sbr->noPatches] > 0)
{
usb = sb;
msb = sb;
sbr->noPatches++;
} else {
msb = sbr->kx;
}
if (sb == sbr->f_master[k])
k = sbr->N_master;
} while (sb != (sbr->kx + sbr->M));
if ((sbr->patchNoSubbands[sbr->noPatches-1] < 3) && (sbr->noPatches > 1))
{
sbr->noPatches--;
}
sbr->noPatches = min(sbr->noPatches, 5);
}
#endif