g7231_lpc.c

G723.1语音压缩解压在tms320c54系列上的实现代码,本人已在CCS上仿真通过. 包含全部源代码,主函数请自已写(本人的就不奉送了:

#include "typedef.h"
#include "G7231_basop.h"
#include "G7231_cst_lbc.h"
#include "G7231_tab_lbc.h"
#include "G7231_lbccodec.h"
#include "G7231_coder.h"
#include "G7231_decod.h"
#include "G7231_util_lbc.h"
#include "G7231_lpc.h"
#include "G7231_cod_cng.h"
#include "intrindefs.h"

void  G7231Comp_Lpc( Word16 *UnqLpc, Word16 *PrevDat, Word16 *DataBuff )
{
    int   i,j,k ;

    Word16   Dpnt[G7231Frame+G7231LpcFrame-G7231SubFrLen] ;
    Word16   Vect[G7231LpcFrame] ;
    Word16   Acf_sf[G7231LpcOrderP1*G7231SubFrames];
    Word16   ShAcf_sf[G7231SubFrames];
    Word16   Exp   ;
    Word16   *curAcf;
    Word16   Pk2;

    Word32   Acc0,Acc1   ;

    /*
     * Generate a buffer of 360 samples.  This consists of 120 samples
     * from the previous frame and 240 samples from the current frame.
     */
    for ( i = 0 ; i < G7231LpcFrame-G7231SubFrLen ; i ++ )
        Dpnt[i] = PrevDat[i] ;
    for ( i = 0 ; i < G7231Frame ; i ++ )
        Dpnt[i+G7231LpcFrame-G7231SubFrLen] = DataBuff[i] ;


    /*
     * Repeat for all subframes
     */
    curAcf = Acf_sf;
    for ( k = 0 ; k < G7231SubFrames ; k ++ ) {


        /*
        * Do windowing
        */

        /* Get block of 180 samples centered around current subframe */
        for ( i = 0 ; i < G7231LpcFrame ; i ++ )
            Vect[i] = Dpnt[k*G7231SubFrLen+i] ;

        /* Normalize */
        ShAcf_sf[k] = G7231Vec_Norm( Vect, (Word16) G7231LpcFrame ) ;

        /* Apply the Hamming window */
        for ( i = 0 ; i < G7231LpcFrame ; i ++ )
            Vect[i] = G7231mult_r(Vect[i], G7231HammingWindowTable[i]) ;


        /*
        * Compute the autocorrelation coefficients
        */

        /* Compute the zeroth-order coefficient (energy) */
        Acc1 = (Word32) 0 ;
        for ( i = 0 ; i < G7231LpcFrame ; i ++ ) {
            Acc0 = G7231L_mult( Vect[i], Vect[i] ) ;
            Acc0 = G7231L_shr( Acc0, (Word16) 1 ) ;
            Acc1 = G7231L_add( Acc1, Acc0 ) ;
        }

        /* Apply a white noise correction factor of (1025/1024) */
        Acc0 = G7231L_shr( Acc1, (Word16) G7231RidgeFact ) ;
        Acc1 = G7231L_add( Acc1, Acc0 ) ;

        /* Normalize the energy */
        Exp = G7231norm_l( Acc1 ) ;
        Acc1 = G7231L_shl( Acc1, Exp ) ;

        curAcf[0] = G7231round( Acc1 ) ;
        if(curAcf[0] == 0) {
            for ( i = 1 ; i <= G7231LpcOrder ; i ++ )
                curAcf[i] = 0;
            ShAcf_sf[k] = 40;
        }

        else {
            /* Compute the rest of the autocorrelation coefficients.
               Multiply them by a binomial coefficients lag window. */
            for ( i = 1 ; i <= G7231LpcOrder ; i ++ )
            {
                Acc1 = (Word32) 0 ;
                for ( j = i ; j < G7231LpcFrame ; j ++ ) 
                {
                    Acc0 = G7231L_mult( Vect[j], Vect[j-i] ) ;
                    Acc0 = G7231L_shr( Acc0, (Word16) 1 ) ;
                    Acc1 = G7231L_add( Acc1, Acc0 ) ;
                }
                Acc0 = G7231L_shl( Acc1, Exp ) ;
                Acc0 = G7231L_mls( Acc0, G7231BinomialWindowTable[i-1] ) ;
                curAcf[i] = G7231round(Acc0) ;
            }
            /* Save Acf scaling factor */
            ShAcf_sf[k] = G7231add(Exp, G7231shl(ShAcf_sf[k], 1));
        }

        /*
         * Apply the Levinson-Durbin algorithm to generate the LPC
         * coefficients
        */
        G7231Durbin( &UnqLpc[k*G7231LpcOrder], &curAcf[1], curAcf[0], &Pk2 );
        G7231CodStat.SinDet <<= 1;
        if ( Pk2 > 0x799a ) {
            G7231CodStat.SinDet ++ ;
        }
        curAcf += G7231LpcOrderP1;
    }

    /* Update sine detector */
    G7231CodStat.SinDet &= 0x7fff ;

    j = G7231CodStat.SinDet ;
    k = 0 ;
    for ( i = 0 ; i < 15 ; i ++ ) {
        k += j & 1 ;
        j >>= 1 ;
    }
    if ( k >= 14 )
        G7231CodStat.SinDet |= 0x8000 ;

    /* Update CNG Acf memories */
    G7231Update_Acf(Acf_sf, ShAcf_sf);

}

Word16  G7231Durbin( Word16 *Lpc, Word16 *Corr, Word16 Err, Word16 *Pk2 )
{
    int   i,j   ;

    Word16   Temp[G7231LpcOrder] ;
    Word16   Pk ;

    Word32   Acc0,Acc1,Acc2 ;

 /*
  * Initialize the LPC vector
  */
    for ( i = 0 ; i < G7231LpcOrder ; i ++ )
        Lpc[i] = (Word16) 0 ;

 /*
  * Do the recursion.  At the ith step, the algorithm computes the
  * (i+1)th - order MMSE linear prediction filter.
  */
    for ( i = 0 ; i < G7231LpcOrder ; i ++ ) {

/*
 * Compute the partial correlation (parcor) coefficient
 */

        /* Start parcor computation */
        Acc0 = G7231L_deposit_h( Corr[i] ) ;
        Acc0 = G7231L_shr( Acc0, (Word16) 2 ) ;
        for ( j = 0 ; j < i ; j ++ )
            Acc0 = G7231L_msu( Acc0, Lpc[j], Corr[i-j-1] ) ;
        Acc0 = G7231L_shl( Acc0, (Word16) 2 ) ;

        /* Save sign */
        Acc1 = Acc0 ;
        Acc0 = G7231L_abs( Acc0 ) ;

        /* Finish parcor computation */
        Acc2 = G7231L_deposit_h( Err ) ;
        if ( Acc0 >= Acc2 ) {
            *Pk2 = 32767;
            break ;
        }

        Pk = G7231div_l( Acc0, Err ) ;

        if ( Acc1 >= 0 )
            Pk = G7231negate(Pk) ;

 /*
  * Sine detector
  */
        if ( i == 1 ) *Pk2 = Pk;

 /*
  * Compute the ith LPC coefficient
  */
        Acc0 = G7231L_deposit_h( G7231negate(Pk) ) ;
        Acc0 = G7231L_shr( Acc0, (Word16) 2 ) ;
        Lpc[i] = G7231round( Acc0 ) ;

 /*
  * Update the prediction error
  */
        Acc1 = G7231L_mls( Acc1, Pk ) ;
        Acc1 = G7231L_add( Acc1, Acc2 ) ;
        Err = G7231round( Acc1 ) ;

 /*
  * Compute the remaining LPC coefficients
  */
        for ( j = 0 ; j < i ; j ++ )
            Temp[j] = Lpc[j] ;

        for ( j = 0 ; j < i ; j ++ ) {
            Acc0 = G7231L_deposit_h( Lpc[j] ) ;
            Acc0 = G7231L_mac( Acc0, Pk, Temp[i-j-1] ) ;
            Lpc[j] = G7231round( Acc0 ) ;
        }
    }

    return Err ;
}

void  G7231Wght_Lpc( Word16 *PerLpc, Word16 *UnqLpc )
{
    int   i,j   ;


 /*
  * Do for all subframes
  */
    for ( i = 0 ; i < G7231SubFrames ; i ++ ) {


 /*
  * Compute the jth FIR coefficient by multiplying the jth LPC
  * coefficient by (0.9)^j.
  */
        for ( j = 0 ; j < G7231LpcOrder ; j ++ )
            PerLpc[j] = G7231mult_r( UnqLpc[j], G7231PerFiltZeroTable[j] ) ;
        PerLpc += G7231LpcOrder ;


/*
 * Compute the jth IIR coefficient by multiplying the jth LPC
 * coefficient by (0.5)^j.
 */
        for ( j = 0 ; j < G7231LpcOrder ; j ++ )
            PerLpc[j] = G7231mult_r( UnqLpc[j], G7231PerFiltPoleTable[j] ) ;
        PerLpc += G7231LpcOrder ;
        UnqLpc += G7231LpcOrder ;
    }
}

void  G7231Error_Wght( Word16 *Dpnt, Word16 *PerLpc )
{
    int   i,j,k ;

    Word32   Acc0  ;


/*
 * Do for all subframes
 */
    for ( k = 0 ; k < G7231SubFrames ; k ++ ) {

        for ( i = 0 ; i < G7231SubFrLen ; i ++ ) {

/*
 * Do the FIR part
 */
            /* Filter */
            Acc0 = G7231L_mult( *Dpnt, (Word16) 0x2000 ) ;
            for ( j = 0 ; j < G7231LpcOrder ; j ++ )
                Acc0 = G7231L_msu( Acc0, PerLpc[j], G7231CodStat.WghtFirDl[j] ) ;

            /* Update memory */
            for ( j = G7231LpcOrder-1 ; j > 0 ; j -- )
                G7231CodStat.WghtFirDl[j] = G7231CodStat.WghtFirDl[j-1] ;
            G7231CodStat.WghtFirDl[0] = *Dpnt ;

 /*
  * Do the IIR part
  */

            /* Filter */
            for ( j = 0 ; j < G7231LpcOrder ; j ++ )
                Acc0 = G7231L_mac( Acc0, PerLpc[G7231LpcOrder+j],
                                                    G7231CodStat.WghtIirDl[j] ) ;
            for ( j = G7231LpcOrder-1 ; j > 0 ; j -- )
                G7231CodStat.WghtIirDl[j] = G7231CodStat.WghtIirDl[j-1] ;
            Acc0 = G7231L_shl( Acc0, (Word16) 2 ) ;

            /* Update memory */
            G7231CodStat.WghtIirDl[0] = G7231round( Acc0 ) ;
            *Dpnt ++ = G7231CodStat.WghtIirDl[0] ;
        }
        PerLpc += 2*G7231LpcOrder ;
    }
}

void  G7231Comp_Ir( Word16 *ImpResp, Word16 *QntLpc, Word16 *PerLpc, G7231PWDEF Pw )
{
    int   i;
    unsigned int j;

    Word16   FirDl[G7231LpcOrder] ;
    Word16   IirDl[G7231LpcOrder] ;
    Word16   Temp[G7231PitchMax+G7231SubFrLen] ;

    Word32   Acc0,Acc1 ;


 /*
  * Clear all memory.  Impulse response calculation requires
  * an all-zero initial state.
  */

    /* Perceptual weighting filter */
    for ( i = 0 ; i < G7231LpcOrder ; i ++ )
        FirDl[i] = IirDl[i] = (Word16) 0 ;

    /* Harmonic noise shaping filter */
    for ( i = 0 ; i < G7231PitchMax+G7231SubFrLen ; i ++ )
        Temp[i] = (Word16) 0 ;


 /*
  * Input a single impulse
  */
    Acc0 = (Word32) 0x04000000L ;

 /*
  * Do for all elements in a subframe
  */
    for ( i = 0 ; i < G7231SubFrLen ; i ++ ) {

 /*
  * Synthesis filter
  */
        for ( j = 0 ; j < G7231LpcOrder ; j ++ )
            Acc0 = G7231L_mac( Acc0, QntLpc[j], FirDl[j] ) ;
        Acc1 = G7231L_shl( Acc0, (Word16) 2 ) ;