sbr_hfgen.c

tcpmp.src.0.72RC1 优秀的多媒体播放器TCPMP的源代码

/*
** 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 1.22 2004/09/08 09:43:11 gcp 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 */
#ifdef SBR_LOW_POWER
static void calc_prediction_coef_lp(sbr_info *sbr, qmf_t Xlow[MAX_NTSRHFG][64],
                                    complex_t *alpha_0, complex_t *alpha_1, real_t *rxx);
static void calc_aliasing_degree(sbr_info *sbr, real_t *rxx, real_t *deg);
#else
static void calc_prediction_coef(sbr_info *sbr, qmf_t Xlow[MAX_NTSRHFG][64],
                                 complex_t *alpha_0, complex_t *alpha_1, uint8_t k);
#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][64],
                   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]];

    calc_chirp_factors(sbr, ch);

#ifdef SBR_LOW_POWER
    memset(deg, 0, 64*sizeof(real_t));
#endif

    if ((ch == 0) && (sbr->Reset))
        patch_construction(sbr);

    /* calculate the prediction coefficients */
#ifdef SBR_LOW_POWER
    calc_prediction_coef_lp(sbr, Xlow, alpha_0, alpha_1, rxx);
    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++)
        {
            real_t a0_r, a0_i, a1_r, a1_i;
            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)
            {
                real_t temp1_r, temp2_r, temp3_r;
#ifndef SBR_LOW_POWER
                real_t temp1_i, temp2_i, temp3_i;
                calc_prediction_coef(sbr, Xlow, alpha_0, alpha_1, p);
#endif

                a0_r = MUL_C(RE(alpha_0[p]), bw);
                a1_r = MUL_C(RE(alpha_1[p]), bw2);
#ifndef SBR_LOW_POWER
                a0_i = MUL_C(IM(alpha_0[p]), bw);
                a1_i = MUL_C(IM(alpha_1[p]), bw2);
#endif

            	temp2_r = QMF_RE(Xlow[first - 2 + offset][p]);
            	temp3_r = QMF_RE(Xlow[first - 1 + offset][p]);
#ifndef SBR_LOW_POWER
            	temp2_i = QMF_IM(Xlow[first - 2 + offset][p]);
            	temp3_i = QMF_IM(Xlow[first - 1 + offset][p]);
#endif
				for (l = first; l < last; l++)
                {
                	temp1_r = temp2_r;
                	temp2_r = temp3_r;
                	temp3_r = QMF_RE(Xlow[l + offset][p]);
#ifndef SBR_LOW_POWER
                	temp1_i = temp2_i;
                	temp2_i = temp3_i;
                    temp3_i = QMF_IM(Xlow[l + offset][p]);
#endif

#ifdef SBR_LOW_POWER
                    QMF_RE(Xhigh[l + offset][k]) =
                        temp3_r
                      +(MUL_R(a0_r, temp2_r) +
                        MUL_R(a1_r, temp1_r));
#else
                    QMF_RE(Xhigh[l + offset][k]) =
                        temp3_r
                      +(MUL_R(a0_r, temp2_r) -
                        MUL_R(a0_i, temp2_i) +
                        MUL_R(a1_r, temp1_r) -
                        MUL_R(a1_i, temp1_i));
                    QMF_IM(Xhigh[l + offset][k]) =
                        temp3_i
                      +(MUL_R(a0_i, temp2_r) +
                        MUL_R(a0_r, temp2_i) +
                        MUL_R(a1_i, temp1_r) +
                        MUL_R(a1_r, temp1_i));
#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;

#ifdef SBR_LOW_POWER
static void auto_correlation(sbr_info *sbr, acorr_coef *ac,
                             qmf_t buffer[MAX_NTSRHFG][64],
                             uint8_t bd, uint8_t len)
{
    real_t r01 = 0, r02 = 0, r11 = 0;
    int8_t j;
    uint8_t offset = sbr->tHFAdj;
#ifdef FIXED_POINT
    const real_t rel = FRAC_CONST(0.999999); // 1 / (1 + 1e-6f);
    uint32_t maxi = 0;
    uint32_t pow2, exp;
#else
    const real_t rel = 1 / (1 + 1e-6f);
#endif


#ifdef FIXED_POINT
    mask = 0;

    for (j = (offset-2); j < (len + offset); j++)
    {
        real_t x;
        x = QMF_RE(buffer[j][bd])>>REAL_BITS;
        mask |= x ^ (x >> 31);
    }

    exp = wl_min_lzc(mask);

    /* improves accuracy */
    if (exp > 0)
        exp -= 1;

    for (j = offset; j < len + offset; j++)
    {
        real_t buf_j = ((QMF_RE(buffer[j][bd])+(1<<(exp-1)))>>exp);
        real_t buf_j_1 = ((QMF_RE(buffer[j-1][bd])+(1<<(exp-1)))>>exp);
        real_t buf_j_2 = ((QMF_RE(buffer[j-2][bd])+(1<<(exp-1)))>>exp);

        /* normalisation with rounding */
        r01 += MUL_R(buf_j, buf_j_1);
        r02 += MUL_R(buf_j, buf_j_2);
        r11 += MUL_R(buf_j_1, buf_j_1);
    }
    RE(ac->r12) = r01 -
        MUL_R(((QMF_RE(buffer[len+offset-1][bd])+(1<<(exp-1)))>>exp), ((QMF_RE(buffer[len+offset-2][bd])+(1<<(exp-1)))>>exp)) +
        MUL_R(((QMF_RE(buffer[offset-1][bd])+(1<<(exp-1)))>>exp), ((QMF_RE(buffer[offset-2][bd])+(1<<(exp-1)))>>exp));
    RE(ac->r22) = r11 -
        MUL_R(((QMF_RE(buffer[len+offset-2][bd])+(1<<(exp-1)))>>exp), ((QMF_RE(buffer[len+offset-2][bd])+(1<<(exp-1)))>>exp)) +
        MUL_R(((QMF_RE(buffer[offset-2][bd])+(1<<(exp-1)))>>exp), ((QMF_RE(buffer[offset-2][bd])+(1<<(exp-1)))>>exp));
#else
    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]);
#endif
    RE(ac->r01) = r01;
    RE(ac->r02) = r02;
    RE(ac->r11) = r11;

    ac->det = MUL_R(RE(ac->r11), RE(ac->r22)) - MUL_F(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][64],
                             uint8_t bd, uint8_t len)
{
    real_t r01r = 0, r01i = 0, r02r = 0, r02i = 0, r11r = 0;
    real_t temp1_r, temp1_i, temp2_r, temp2_i, temp3_r, temp3_i, temp4_r, temp4_i, temp5_r, temp5_i;
#ifdef FIXED_POINT
    const real_t rel = FRAC_CONST(0.999999); // 1 / (1 + 1e-6f);
    uint32_t mask, exp;
    real_t pow2_to_exp;
#else
    const real_t rel = 1 / (1 + 1e-6f);
#endif
    int8_t j;
    uint8_t offset = sbr->tHFAdj;

#ifdef FIXED_POINT
    mask = 0;

    for (j = (offset-2); j < (len + offset); j++)
    {
        real_t x;
        x = QMF_RE(buffer[j][bd])>>REAL_BITS;
        mask |= x ^ (x >> 31);
        x = QMF_IM(buffer[j][bd])>>REAL_BITS;
        mask |= x ^ (x >> 31);
    }

    exp = wl_min_lzc(mask);

    /* improves accuracy */
    if (exp > 0)
        exp -= 1;
   
    pow2_to_exp = 1<<(exp-1);

    temp2_r = (QMF_RE(buffer[offset-2][bd]) + pow2_to_exp) >> exp;
    temp2_i = (QMF_IM(buffer[offset-2][bd]) + pow2_to_exp) >> exp;
    temp3_r = (QMF_RE(buffer[offset-1][bd]) + pow2_to_exp) >> exp;
    temp3_i = (QMF_IM(buffer[offset-1][bd]) + pow2_to_exp) >> exp;
    // Save these because they are needed after loop
    temp4_r = temp2_r;
    temp4_i = temp2_i;
    temp5_r = temp3_r;
    temp5_i = temp3_i;

    for (j = offset; j < len + offset; j++)
    {
    	temp1_r = temp2_r; // temp1_r = (QMF_RE(buffer[offset-2][bd] + (1<<(exp-1))) >> exp;
    	temp1_i = temp2_i; // temp1_i = (QMF_IM(buffer[offset-2][bd] + (1<<(exp-1))) >> exp;
    	temp2_r = temp3_r; // temp2_r = (QMF_RE(buffer[offset-1][bd] + (1<<(exp-1))) >> exp;
    	temp2_i = temp3_i; // temp2_i = (QMF_IM(buffer[offset-1][bd] + (1<<(exp-1))) >> exp;
        temp3_r = (QMF_RE(buffer[j][bd]) + pow2_to_exp) >> exp;
        temp3_i = (QMF_IM(buffer[j][bd]) + pow2_to_exp) >> exp;
        r01r += MUL_R(temp3_r, temp2_r) + MUL_R(temp3_i, temp2_i);
        r01i += MUL_R(temp3_i, temp2_r) - MUL_R(temp3_r, temp2_i);
        r02r += MUL_R(temp3_r, temp1_r) + MUL_R(temp3_i, temp1_i);
        r02i += MUL_R(temp3_i, temp1_r) - MUL_R(temp3_r, temp1_i);
        r11r += MUL_R(temp2_r, temp2_r) + MUL_R(temp2_i, temp2_i);
    }

    // These are actual values in temporary variable at this point
    // temp1_r = (QMF_RE(buffer[len+offset-1-2][bd] + (1<<(exp-1))) >> exp;
    // temp1_i = (QMF_IM(buffer[len+offset-1-2][bd] + (1<<(exp-1))) >> exp;
    // temp2_r = (QMF_RE(buffer[len+offset-1-1][bd] + (1<<(exp-1))) >> exp;
    // temp2_i = (QMF_IM(buffer[len+offset-1-1][bd] + (1<<(exp-1))) >> exp;
    // temp3_r = (QMF_RE(buffer[len+offset-1][bd]) + (1<<(exp-1))) >> exp;
    // temp3_i = (QMF_IM(buffer[len+offset-1][bd]) + (1<<(exp-1))) >> exp;
    // temp4_r = (QMF_RE(buffer[offset-2][bd]) + (1<<(exp-1))) >> exp;