sbr_hfadj.c

这是著名的TCPMP播放器在WINDWOWS,和WINCE下编译通过的源程序.笔者对其中的LIBMAD库做了针对ARM MPU的优化. 并增加了词幕功能.

/*
** 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_hfadj.c,v 1.18 2004/09/04 14:56:28 menno Exp $
**/

/* High Frequency adjustment */

#include "common.h"
#include "structs.h"

#ifdef SBR_DEC

#include "sbr_syntax.h"
#include "sbr_hfadj.h"

#include "sbr_noise.h"


/* static function declarations */
static void estimate_current_envelope(sbr_info *sbr, sbr_hfadj_info *adj,
                                      qmf_t Xsbr[MAX_NTSRHFG][64], uint8_t ch);
static void calculate_gain(sbr_info *sbr, sbr_hfadj_info *adj, uint8_t ch);
#ifdef SBR_LOW_POWER
static void calc_gain_groups(sbr_info *sbr, sbr_hfadj_info *adj, real_t *deg, uint8_t ch);
static void aliasing_reduction(sbr_info *sbr, sbr_hfadj_info *adj, real_t *deg, uint8_t ch);
#endif
static void hf_assembly(sbr_info *sbr, sbr_hfadj_info *adj, qmf_t Xsbr[MAX_NTSRHFG][64], uint8_t ch);


void hf_adjustment(sbr_info *sbr, qmf_t Xsbr[MAX_NTSRHFG][64]
#ifdef SBR_LOW_POWER
                   ,real_t *deg /* aliasing degree */
#endif
                   ,uint8_t ch)
{
    ALIGN sbr_hfadj_info adj = {{{0}}};

    if (sbr->bs_frame_class[ch] == FIXFIX)
    {
        sbr->l_A[ch] = -1;
    } else if (sbr->bs_frame_class[ch] == VARFIX) {
        if (sbr->bs_pointer[ch] > 1)
            sbr->l_A[ch] = -1;
        else
            sbr->l_A[ch] = sbr->bs_pointer[ch] - 1;
    } else {
        if (sbr->bs_pointer[ch] == 0)
            sbr->l_A[ch] = -1;
        else
            sbr->l_A[ch] = sbr->L_E[ch] + 1 - sbr->bs_pointer[ch];
    }

    estimate_current_envelope(sbr, &adj, Xsbr, ch);

    calculate_gain(sbr, &adj, ch);

#ifdef SBR_LOW_POWER
    calc_gain_groups(sbr, &adj, deg, ch);
    aliasing_reduction(sbr, &adj, deg, ch);
#endif

    hf_assembly(sbr, &adj, Xsbr, ch);
}

static uint8_t get_S_mapped(sbr_info *sbr, uint8_t ch, uint8_t l, uint8_t current_band)
{
    if (sbr->f[ch][l] == HI_RES)
    {
        /* in case of using f_table_high we just have 1 to 1 mapping
         * from bs_add_harmonic[l][k]
         */
        if ((l >= sbr->l_A[ch]) ||
            (sbr->bs_add_harmonic_prev[ch][current_band] && sbr->bs_add_harmonic_flag_prev[ch]))
        {
            return sbr->bs_add_harmonic[ch][current_band];
        }
    } else {
        uint8_t b, lb, ub;

        /* in case of f_table_low we check if any of the HI_RES bands
         * within this LO_RES band has bs_add_harmonic[l][k] turned on
         * (note that borders in the LO_RES table are also present in
         * the HI_RES table)
         */

        /* find first HI_RES band in current LO_RES band */
        lb = 2*current_band - ((sbr->N_high & 1) ? 1 : 0);
        /* find first HI_RES band in next LO_RES band */
        ub = 2*(current_band+1) - ((sbr->N_high & 1) ? 1 : 0);

        /* check all HI_RES bands in current LO_RES band for sinusoid */
        for (b = lb; b < ub; b++)
        {
            if ((l >= sbr->l_A[ch]) ||
                (sbr->bs_add_harmonic_prev[ch][b] && sbr->bs_add_harmonic_flag_prev[ch]))
            {
                if (sbr->bs_add_harmonic[ch][b] == 1)
                    return 1;
            }
        }
    }

    return 0;
}

static void estimate_current_envelope(sbr_info *sbr, sbr_hfadj_info *adj,
                                      qmf_t Xsbr[MAX_NTSRHFG][64], uint8_t ch)
{
    uint8_t m, l, j, k, k_l, k_h, p;
    real_t nrg, div;

    if (sbr->bs_interpol_freq == 1)
    {
        for (l = 0; l < sbr->L_E[ch]; l++)
        {
            uint8_t i, l_i, u_i;

            l_i = sbr->t_E[ch][l];
            u_i = sbr->t_E[ch][l+1];

            div = (real_t)(u_i - l_i);

            for (m = 0; m < sbr->M; m++)
            {
                nrg = 0;

                for (i = l_i + sbr->tHFAdj; i < u_i + sbr->tHFAdj; i++)
                {
#ifdef FIXED_POINT
#ifdef SBR_LOW_POWER
                    nrg += ((QMF_RE(Xsbr[i][m + sbr->kx])+(1<<(REAL_BITS-1)))>>REAL_BITS)*((QMF_RE(Xsbr[i][m + sbr->kx])+(1<<(REAL_BITS-1)))>>REAL_BITS);
#else
                    nrg += ((QMF_RE(Xsbr[i][m + sbr->kx])+(1<<(REAL_BITS-1)))>>REAL_BITS)*((QMF_RE(Xsbr[i][m + sbr->kx])+(1<<(REAL_BITS-1)))>>REAL_BITS) +
                        ((QMF_IM(Xsbr[i][m + sbr->kx])+(1<<(REAL_BITS-1)))>>REAL_BITS)*((QMF_IM(Xsbr[i][m + sbr->kx])+(1<<(REAL_BITS-1)))>>REAL_BITS);
#endif
#else
                    nrg += MUL_R(QMF_RE(Xsbr[i][m + sbr->kx]), QMF_RE(Xsbr[i][m + sbr->kx]))
#ifndef SBR_LOW_POWER
                        + MUL_R(QMF_IM(Xsbr[i][m + sbr->kx]), QMF_IM(Xsbr[i][m + sbr->kx]))
#endif
                        ;
#endif
                }

                sbr->E_curr[ch][m][l] = nrg / div;
#ifdef SBR_LOW_POWER
#ifdef FIXED_POINT
                sbr->E_curr[ch][m][l] <<= 1;
#else
                sbr->E_curr[ch][m][l] *= 2;
#endif
#endif
            }
        }
    } else {
        for (l = 0; l < sbr->L_E[ch]; l++)
        {
            for (p = 0; p < sbr->n[sbr->f[ch][l]]; p++)
            {
                k_l = sbr->f_table_res[sbr->f[ch][l]][p];
                k_h = sbr->f_table_res[sbr->f[ch][l]][p+1];

                for (k = k_l; k < k_h; k++)
                {
                    uint8_t i, l_i, u_i;
                    nrg = 0;

                    l_i = sbr->t_E[ch][l];
                    u_i = sbr->t_E[ch][l+1];

                    div = (real_t)((u_i - l_i)*(k_h - k_l));

                    for (i = l_i + sbr->tHFAdj; i < u_i + sbr->tHFAdj; i++)
                    {
                        for (j = k_l; j < k_h; j++)
                        {
#ifdef FIXED_POINT
#ifdef SBR_LOW_POWER
                            nrg += ((QMF_RE(Xsbr[i][j])+(1<<(REAL_BITS-1)))>>REAL_BITS)*((QMF_RE(Xsbr[i][j])+(1<<(REAL_BITS-1)))>>REAL_BITS);
#else
                            nrg += ((QMF_RE(Xsbr[i][j])+(1<<(REAL_BITS-1)))>>REAL_BITS)*((QMF_RE(Xsbr[i][j])+(1<<(REAL_BITS-1)))>>REAL_BITS) +
                                ((QMF_IM(Xsbr[i][j])+(1<<(REAL_BITS-1)))>>REAL_BITS)*((QMF_IM(Xsbr[i][j])+(1<<(REAL_BITS-1)))>>REAL_BITS);
#endif
#else
                            nrg += MUL_R(QMF_RE(Xsbr[i][j]), QMF_RE(Xsbr[i][j]))
#ifndef SBR_LOW_POWER
                                + MUL_R(QMF_IM(Xsbr[i][j]), QMF_IM(Xsbr[i][j]))
#endif
                                ;
#endif
                        }
                    }

                    sbr->E_curr[ch][k - sbr->kx][l] = nrg / div;
#ifdef SBR_LOW_POWER
#ifdef FIXED_POINT
                    sbr->E_curr[ch][k - sbr->kx][l] <<= 1;
#else
                    sbr->E_curr[ch][k - sbr->kx][l] *= 2;
#endif
#endif
                }
            }
        }
    }
}