LPCdecode.c File Reference

#include <math.h>
#include <string.h>
#include "helpfun.h"
#include "lsf.h"
#include "iLBC_define.h"
#include "constants.h"

Include dependency graph for LPCdecode.c:

Go to the source code of this file.

Functions
void	DecoderInterpolateLSF (float *syntdenum, float *weightdenum, float *lsfdeq, int length, iLBC_Dec_Inst_t *iLBCdec_inst)
void	LSFinterpolate2a_dec (float *a, float *lsf1, float *lsf2, float coef, int length)
void	SimplelsfDEQ (float *lsfdeq, int *index, int lpc_n)

Function Documentation

DecoderInterpolateLSF()

void DecoderInterpolateLSF	(	float *	syntdenum,
		float *	weightdenum,
		float *	lsfdeq,
		int	length,
		iLBC_Dec_Inst_t *	iLBCdec_inst
	)

Definition at line 89 of file LPCdecode.c.

References bwexpand(), LPC_CHIRP_WEIGHTDENUM, LPC_FILTERORDER, lsf_weightTbl_20ms, lsf_weightTbl_30ms, iLBC_Dec_Inst_t_::lsfdeqold, LSFinterpolate2a_dec(), iLBC_Dec_Inst_t_::mode, and iLBC_Dec_Inst_t_::nsub.

Referenced by iLBC_decode().

    {
       int    i, pos, lp_length;
       float  lp[LPC_FILTERORDER + 1], *lsfdeq2;






       lsfdeq2 = lsfdeq + length;
       lp_length = length + 1;

       if (iLBCdec_inst->mode==30) {
           /* sub-frame 1: Interpolation between old and first */

           LSFinterpolate2a_dec(lp, iLBCdec_inst->lsfdeqold, lsfdeq,
               lsf_weightTbl_30ms[0], length);
           memcpy(syntdenum,lp,lp_length*sizeof(float));
           bwexpand(weightdenum, lp, LPC_CHIRP_WEIGHTDENUM,
               lp_length);

           /* sub-frames 2 to 6: interpolation between first
              and last LSF */

           pos = lp_length;
           for (i = 1; i < 6; i++) {
               LSFinterpolate2a_dec(lp, lsfdeq, lsfdeq2,
                   lsf_weightTbl_30ms[i], length);
               memcpy(syntdenum + pos,lp,lp_length*sizeof(float));
               bwexpand(weightdenum + pos, lp,
                   LPC_CHIRP_WEIGHTDENUM, lp_length);
               pos += lp_length;
           }
       }
       else {
           pos = 0;
           for (i = 0; i < iLBCdec_inst->nsub; i++) {
               LSFinterpolate2a_dec(lp, iLBCdec_inst->lsfdeqold,
                   lsfdeq, lsf_weightTbl_20ms[i], length);
               memcpy(syntdenum+pos,lp,lp_length*sizeof(float));
               bwexpand(weightdenum+pos, lp, LPC_CHIRP_WEIGHTDENUM,
                   lp_length);
               pos += lp_length;
           }
       }

       /* update memory */

       if (iLBCdec_inst->mode==30)
           memcpy(iLBCdec_inst->lsfdeqold, lsfdeq2,
                       length*sizeof(float));
       else
           memcpy(iLBCdec_inst->lsfdeqold, lsfdeq,
                       length*sizeof(float));

   }

LSFinterpolate2a_dec()

void LSFinterpolate2a_dec	(	float *	a,
		float *	lsf1,
		float *	lsf2,
		float	coef,
		int	length
	)

Definition at line 25 of file LPCdecode.c.

References interpolate(), LPC_FILTERORDER, and lsf2a().

Referenced by DecoderInterpolateLSF().

    {
       float  lsftmp[LPC_FILTERORDER];

       interpolate(lsftmp, lsf1, lsf2, coef, length);
       lsf2a(a, lsftmp);
   }

SimplelsfDEQ()

void SimplelsfDEQ	(	float *	lsfdeq,
		int *	index,
		int	lpc_n
	)

Definition at line 42 of file LPCdecode.c.

References dim_lsfCbTbl, LPC_FILTERORDER, LSF_NSPLIT, lsfCbTbl, and size_lsfCbTbl.

Referenced by iLBC_decode().

    {
       int i, j, pos, cb_pos;





       /* decode first LSF */

       pos = 0;
       cb_pos = 0;
       for (i = 0; i < LSF_NSPLIT; i++) {
           for (j = 0; j < dim_lsfCbTbl[i]; j++) {
               lsfdeq[pos + j] = lsfCbTbl[cb_pos +
                   (long)(index[i])*dim_lsfCbTbl[i] + j];
           }
           pos += dim_lsfCbTbl[i];
           cb_pos += size_lsfCbTbl[i]*dim_lsfCbTbl[i];
       }

       if (lpc_n>1) {

           /* decode last LSF */

           pos = 0;
           cb_pos = 0;
           for (i = 0; i < LSF_NSPLIT; i++) {
               for (j = 0; j < dim_lsfCbTbl[i]; j++) {
                   lsfdeq[LPC_FILTERORDER + pos + j] =
                       lsfCbTbl[cb_pos +
                       (long)(index[LSF_NSPLIT + i])*
                       dim_lsfCbTbl[i] + j];
               }
               pos += dim_lsfCbTbl[i];
               cb_pos += size_lsfCbTbl[i]*dim_lsfCbTbl[i];
           }
       }
   }