qua_lspe.c

语音压缩编码中的g729p编码程序

/*
   ITU-T G.729 Annex C+ - Reference C code for floating point
                         implementation of G.729 Annex C+
                         (integration of Annexes B, D and E)
                          Version 2.1 of October 1999
*/

/*
 File : QUA_LSPE.C
*/

/*----------------------------------------------------------*
 *  qua_lsp.c                                               *
 *  ~~~~~~~~                                                *
 * Functions related to the quantization of LSP's           *
 *----------------------------------------------------------*/
#include <math.h>
#include "typedef.h"
#include "ld8k.h"
#include "tab_ld8k.h"
#include "ld8cp.h"
#include "tabld8cp.h"

/* Prototype definitions of static functions */
void get_wegt( FLOAT flsp[], FLOAT wegt[] );
static void lsp_pre_select( FLOAT rbuf[], FLOAT lspcb1[][M], int *cand);
static void lsp_select_1( FLOAT rbuf[], FLOAT lspcb1[], FLOAT wegt[],
                         FLOAT lspcb2[][M], int *index );
static void lsp_select_2( FLOAT rbuf[], FLOAT lspcb1[], FLOAT wegt[],
                         FLOAT  lspcb2[][M], int *index );
static void lsp_last_select( FLOAT tdist[MODE], int *mode_index );
static void lsp_get_tdist( FLOAT wegt[], FLOAT buf[],
                          FLOAT *tdist, FLOAT rbuf[], FLOAT fg_sum[] );
void qua_lspe(
    FLOAT lsp[],       /* (i) : Unquantized LSP            */
    FLOAT lsp_q[],     /* (o) : Quantized LSP              */
    int ana[],          /* (o) : indexes                    */
    FLOAT freq_prev[MA_NP][M],    /* (i) : previous LSP MA vector        */
    FLOAT freq_cur[]   /* (o) : current LSP MA vector        */
)
{
    int i;
    FLOAT lsf[M], lsf_q[M];  /* domain 0.0<= lsf <PI */
    
    /* Convert LSPs to LSFs */
    for (i=0; i<M; i++ )
        lsf[i] = (FLOAT)acos(lsp[i]);
    
    lsp_qua_cse(lsf, lsf_q, ana, freq_prev, freq_cur );
    
    /* Convert LSFs to LSPs */
    for (i=0; i<M; i++ )
        lsp_q[i] = (FLOAT)cos(lsf_q[i]);
    
    return;
}

/*----------------------------------------------------------------------------
* lsp_encw_reset - set the previous LSP vector
*----------------------------------------------------------------------------
*/
void lsp_encw_resete(
    FLOAT freq_prev[MA_NP][M]    /* (i) : previous LSP MA vector        */
)
{
    int  i;
    for(i=0; i<MA_NP; i++)
        copy (&freq_prev_reset[0], &freq_prev[i][0], M );
    return;
}
/*----------------------------------------------------------------------------
* lsp_qua_cs - lsp quantizer
*----------------------------------------------------------------------------
*/
void lsp_qua_cse(
    FLOAT  *flsp_in,       /*  input : Original LSP parameters      */
    FLOAT  *lspq_out,       /*  output: Quantized LSP parameters     */
    int  *code,             /*  output: codes of the selected LSP    */
    FLOAT freq_prev[MA_NP][M],    /* (i)  : previous LSP MA vector        */
    FLOAT freq_cur[]     /* (o)  : current LSP MA vector        */
)
{
    FLOAT wegt[M];   /* weight coef. */
    
    get_wegt( flsp_in, wegt );
    
    relspwede( flsp_in, wegt, lspq_out, lspcb1, lspcb2, fg,
        freq_prev, fg_sum, fg_sum_inv, code, freq_cur);
    return;
}
/*----------------------------------------------------------------------------
* relspwed -
*----------------------------------------------------------------------------
*/
void relspwede(
    FLOAT  lsp[],                  /*input: unquantized LSP parameters  */
    FLOAT  wegt[],                 /*input: weight coef.                */
    FLOAT  lspq[],                 /*output:quantized LSP parameters    */
    FLOAT  lspcb1[][M],            /*input: first stage LSP codebook    */
    FLOAT  lspcb2[][M],            /*input: Second stage LSP codebook   */
    FLOAT  fg[MODE][MA_NP][M],     /*input: MA prediction coef.         */
    FLOAT  freq_prev[MA_NP][M],    /*input: previous LSP vector         */
    FLOAT  fg_sum[MODE][M],        /*input: present MA prediction coef. */
    FLOAT  fg_sum_inv[MODE][M],    /*input: inverse coef.               */
    int    code_ana[],              /*output:codes of the selected LSP   */
    FLOAT freq_cur[]             /* (o) : current LSP MA vector        */
)
{
    int  mode, j;
    int  index, mode_index;
    int  cand[MODE], cand_cur;
    int  tindex1[MODE], tindex2[MODE];
    FLOAT tdist[MODE];
    FLOAT rbuf[M];
    FLOAT buf[M];
    
    for(mode = 0; mode<MODE; mode++) {
        
        lsp_prev_extract(lsp, rbuf, fg[mode], freq_prev, fg_sum_inv[mode]);
        
        /*----- search the first stage lsp codebook -----*/
        lsp_pre_select(rbuf, lspcb1, &cand_cur);
        cand[mode]=cand_cur;
        
        /*----- search the second stage lsp codebook (lower 0-4) ----- */
        lsp_select_1(rbuf, lspcb1[cand_cur], wegt, lspcb2, &index);
        
        tindex1[mode] = index;
        
        for(j=0; j<NC; j++)
            buf[j]=lspcb1[cand_cur][j]+lspcb2[index][j];
        
        lsp_expand_1(buf, GAP1);  /* check */
        
        /*----- search the second stage lsp codebook (Higher 5-9) ----- */
        lsp_select_2(rbuf, lspcb1[cand_cur], wegt, lspcb2,
            &index);
        
        tindex2[mode] = index;
        
        for(j=NC; j<M; j++)
            buf[j]=lspcb1[cand_cur][j]+lspcb2[index][j];
        lsp_expand_2(buf, GAP1);  /* check */
        
        
        /* check */
        lsp_expand_1_2(buf, GAP2);
        
        lsp_get_tdist(wegt, buf, &tdist[mode], rbuf,
            fg_sum[mode]);  /* calculate the distortion */
        
    } /* mode */
    
    
    lsp_last_select(tdist, &mode_index); /* select the codes */
    
    /* pack codes for lsp parameters */
    code_ana[0] = (mode_index<<NC0_B) | cand[mode_index];
    code_ana[1] = (tindex1[mode_index]<<NC1_B) | tindex2[mode_index];
    
    /* reconstruct quantized LSP parameter and check the stabilty */
    lsp_get_quante(lspcb1, lspcb2, cand[mode_index],
        tindex1[mode_index], tindex2[mode_index],
        fg[mode_index],
        freq_prev,
        lspq, fg_sum[mode_index], freq_cur);
    
    return;
}
/*----------------------------------------------------------------------------
* lsp_pre_select - select the code of first stage lsp codebook
*----------------------------------------------------------------------------
*/
static void lsp_pre_select(
    FLOAT  rbuf[],         /*input : target vetor             */
    FLOAT  lspcb1[][M],    /*input : first stage lsp codebook */
    int    *cand           /*output: selected code            */
)
{
    int  i, j;
    FLOAT dmin, dist, temp;
    
    /* calculate the distortion */
    *cand = 0;
    dmin= FLT_MAX_G729;
    for(i=0; i<NC0; i++) {
        dist =(F)0.;
        for(j=0; j<M; j++){
            temp = rbuf[j]-lspcb1[i][j];
            dist += temp * temp;
        }
        
        if(dist<dmin)
        {
            dmin=dist;
            *cand=i;
        }
    }
    return;
}

/*----------------------------------------------------------------------------
* lsp_pre_select_1 - select the code of second stage lsp codebook (lower 0-4)
*----------------------------------------------------------------------------
*/
static void lsp_select_1(
    FLOAT  rbuf[],         /*input : target vector            */
    FLOAT  lspcb1[],       /*input : first stage lsp codebook */
    FLOAT  wegt[],         /*input : weight coef.             */
    FLOAT  lspcb2[][M],    /*input : second stage lsp codebook*/
    int    *index          /*output: selected codebook index     */
)
{
    int  j, k1;
    FLOAT buf[M];
    FLOAT dist, dmin, tmp;
    
    for(j=0; j<NC; j++)
        buf[j]=rbuf[j]-lspcb1[j];
    
    *index = 0;
    dmin=FLT_MAX_G729;
    for(k1 = 0; k1<NC1; k1++) {
        /* calculate the distortion */
        dist = (F)0.;
        for(j=0; j<NC; j++) {
            tmp = buf[j]-lspcb2[k1][j];
            dist += wegt[j] * tmp * tmp;
        }
        
        if(dist<dmin) {
            dmin = dist;
            *index = k1;
        }
    }
    return;
}

/*----------------------------------------------------------------------------
* lsp_pre_select_2 - select the code of second stage lsp codebook (higher 5-9)
*----------------------------------------------------------------------------
*/
static void lsp_select_2(
    FLOAT  rbuf[],         /*input : target vector            */
    FLOAT  lspcb1[],       /*input : first stage lsp codebook */
    FLOAT  wegt[],         /*input : weighting coef.             */
    FLOAT  lspcb2[][M],    /*input : second stage lsp codebook*/
    int    *index          /*output: selected codebook index    */
)
{
    int  j, k1;
    FLOAT buf[M];
    FLOAT dist, dmin, tmp;
    
    for(j=NC; j<M; j++)
        buf[j]=rbuf[j]-lspcb1[j];
    
    
    *index = 0;
    dmin= FLT_MAX_G729;
    for(k1 = 0; k1<NC1; k1++) {
        dist = (F)0.0;
        for(j=NC; j<M; j++) {
            tmp = buf[j] - lspcb2[k1][j];
            dist += wegt[j] * tmp * tmp;
        }
        
        if(dist<dmin) {
            dmin = dist;
            *index = k1;
        }
    }
    return;
}
/*----------------------------------------------------------------------------
* lsp_get_tdist - calculate the distortion
*----------------------------------------------------------------------------
*/
static void lsp_get_tdist(
    FLOAT  wegt[],         /*input : weight coef.          */
    FLOAT  buf[],          /*input : candidate LSP vector  */
    FLOAT  *tdist,         /*output: distortion            */
    FLOAT  rbuf[],         /*input : target vector         */
    FLOAT  fg_sum[]        /*input : present MA prediction coef.  */
)
{
    int  j;
    FLOAT tmp;
    
    *tdist = (F)0.0;
    for(j=0; j<M; j++) {
        tmp = (buf[j] - rbuf[j]) * fg_sum[j];
        *tdist += wegt[j] * tmp * tmp;
    }
    return;
}

/*----------------------------------------------------------------------------
* lsp_last_select - select the mode
*----------------------------------------------------------------------------
*/
static void lsp_last_select(
    FLOAT  tdist[],        /*input : distortion         */
    int    *mode_index     /*output: the selected mode  */
)
{
    *mode_index = 0;
    if( tdist[1] < tdist[0] ) *mode_index = 1;
    return;
}
/*----------------------------------------------------------------------------
* get_wegt - compute lsp weights
*----------------------------------------------------------------------------
*/
void get_wegt(
    FLOAT  flsp[],         /* input : M LSP parameters */
    FLOAT  wegt[]          /* output: M weighting coefficients */
)
{
    int  i;
    FLOAT        tmp;
    
    tmp = flsp[1] - PI04 - (F)1.0;
    if (tmp > (F)0.0)       wegt[0] = (F)1.0;
    else         wegt[0] = tmp * tmp * (F)10. + (F)1.0;
    
    for ( i=1; i<M-1; i++ ) {
        tmp = flsp[i+1] - flsp[i-1] - (F)1.0;
        if (tmp > (F)0.0)    wegt[i] = (F)1.0;
        else              wegt[i] = tmp * tmp * (F)10. + (F)1.0;
    }
    
    tmp = PI92 - flsp[M-2] - (F)1.0;
    if (tmp > (F)0.0)       wegt[M-1] = (F)1.0;
    else         wegt[M-1] = tmp * tmp * (F)10. + (F)1.0;
    
    wegt[4] *= CONST12;
    wegt[5] *= CONST12;
    return;
}