sbr_hfgen.c

mpeg4 video codec mpeg4 video codec

/*
** 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 [e-mail].
**
** $Id: sbr_hfgen.c,v 1.1 2006/02/23 14:38:10 kevin-fu 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"


/* static function declarations */
static void calc_prediction_coef(sbr_info *sbr, qmf_t Xlow[MAX_NTSRHFG][32],
                                 complex_t *alpha_0, complex_t *alpha_1
#ifdef SBR_LOW_POWER
                                 , real_t *rxx
#endif
                                 );
#ifdef SBR_LOW_POWER
static void calc_aliasing_degree(sbr_info *sbr, real_t *rxx, real_t *deg);
#endif
static void calc_chirp_factors(sbr_info *sbr, uint8_t ch);
static void patch_construction(sbr_info *sbr);


void hf_generation(sbr_info *sbr, 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;
    ALIGN complex_t alpha_0[64], alpha_1[64];
#ifdef SBR_LOW_POWER
    ALIGN real_t rxx[64];
#endif

    uint8_t offset = sbr->tHFAdj;
    uint8_t first = sbr->t_E[ch][0];
    uint8_t last = sbr->t_E[ch][sbr->L_E[ch]];

//    printf("%d %d\n", first, last);

    calc_chirp_factors(sbr, ch);

    for (i = first; i < last; i++)
    {
        memset(Xhigh[i + offset], 0, 64 * sizeof(qmf_t));
    }

    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(bw, bw);

            /* do the patching */
            /* with or without filtering */
            if (bw2 > 0)
            {
                RE(a0) = MUL_C(RE(alpha_0[p]), bw);
                RE(a1) = MUL_C(RE(alpha_1[p]), bw2);
#ifndef SBR_LOW_POWER
                IM(a0) = MUL_C(IM(alpha_0[p]), bw);
                IM(a1) = MUL_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_R(RE(a0), QMF_RE(Xlow[l - 1 + offset][p])) +
                        MUL_R(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,
                             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 = sbr->tHFAdj;
    const real_t rel = 1 / (1 + 1e-6f);


    for (j = offset; j < len + offset; j++)
    {
        r01 += QMF_RE(buffer[j][bd]) * QMF_RE(buffer[j-1][bd]);
        r02 += QMF_RE(buffer[j][bd]) * QMF_RE(buffer[j-2][bd]);
        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_R(RE(ac->r11), RE(ac->r22)) - MUL_C(MUL_R(RE(ac->r12), RE(ac->r12)), rel);
}
#else
static void auto_correlation(sbr_info *sbr, acorr_coef *ac, 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 = 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])) +