statesearchw.c

Ilibc 语音编解码库算法。语音质量高。接口简单。

   
   /******************************************************************
   
       iLBC Speech Coder ANSI-C Source Code
   
       StateSearchW.c 
   
       Copyright (C) The Internet Society (2004). 
       All Rights Reserved.
   
   ******************************************************************/
   
   #include <math.h> 
   #include <string.h>
   
   #include "iLBC_define.h"
   #include "constants.h"
   #include "filter.h"
   #include "helpfun.h"
   
   /*----------------------------------------------------------------*
    *  predictive noise shaping encoding of scaled start state 
    *  (subrutine for StateSearchW) 
    *---------------------------------------------------------------*/
   
   void AbsQuantW(
       iLBC_Enc_Inst_t *iLBCenc_inst,  
                           /* (i) Encoder instance */
       float *in,          /* (i) vector to encode */
       float *syntDenum,   /* (i) denominator of synthesis filter */
       float *weightDenum, /* (i) denominator of weighting filter */
       int *out,           /* (o) vector of quantizer indexes */
       int len,        /* (i) length of vector to encode and 
                                  vector of quantizer indexes */
       int state_first     /* (i) position of start state in the 
                                  80 vec */
   ){
       float *syntOut;
       float syntOutBuf[LPC_FILTERORDER+STATE_SHORT_LEN_30MS];
       float toQ, xq;
       int n;
       int index;
   
       /* initialization of buffer for filtering */
               
       memset(syntOutBuf, 0, LPC_FILTERORDER*sizeof(float));
   
   
   
       /* initialization of pointer for filtering */
   
       syntOut = &syntOutBuf[LPC_FILTERORDER];
       
       /* synthesis and weighting filters on input */
       
       if (state_first) {
           AllPoleFilter (in, weightDenum, SUBL, LPC_FILTERORDER);
       } else {
           AllPoleFilter (in, weightDenum, 
               iLBCenc_inst->state_short_len-SUBL, 
               LPC_FILTERORDER);
       }
   
       /* encoding loop */
   
       for (n=0; n<len; n++) {
           
           /* time update of filter coefficients */  
           
           if ((state_first)&&(n==SUBL)){
               syntDenum += (LPC_FILTERORDER+1);
               weightDenum += (LPC_FILTERORDER+1);
   
               /* synthesis and weighting filters on input */
               AllPoleFilter (&in[n], weightDenum, len-n, 
                   LPC_FILTERORDER);
   
           } else if ((state_first==0)&&
               (n==(iLBCenc_inst->state_short_len-SUBL))) {
               syntDenum += (LPC_FILTERORDER+1);
               weightDenum += (LPC_FILTERORDER+1);
   
               /* synthesis and weighting filters on input */
               AllPoleFilter (&in[n], weightDenum, len-n, 
                   LPC_FILTERORDER);
               
           }
           
           /* prediction of synthesized and weighted input */
   
           syntOut[n] = 0.0;
           AllPoleFilter (&syntOut[n], weightDenum, 1, 
               LPC_FILTERORDER);
           
           /* quantization */      
   
           toQ = in[n]-syntOut[n];
           sort_sq(&xq, &index, toQ, state_sq3Tbl, 8);
           out[n]=index;
           syntOut[n] = state_sq3Tbl[out[n]];
   
           /* update of the prediction filter */
   
   
   
           AllPoleFilter(&syntOut[n], weightDenum, 1, 
               LPC_FILTERORDER);
       }
   }
   
   /*----------------------------------------------------------------*
    *  encoding of start state                          
    *---------------------------------------------------------------*/
   
   void StateSearchW( 
       iLBC_Enc_Inst_t *iLBCenc_inst,  
                           /* (i) Encoder instance */
       float *residual,/* (i) target residual vector */
       float *syntDenum,   /* (i) lpc synthesis filter */
       float *weightDenum, /* (i) weighting filter denuminator */
       int *idxForMax,     /* (o) quantizer index for maximum 
                                  amplitude */
       int *idxVec,    /* (o) vector of quantization indexes */
       int len,        /* (i) length of all vectors */
       int state_first     /* (i) position of start state in the 
                                  80 vec */
   ){  
       float dtmp, maxVal;
       float tmpbuf[LPC_FILTERORDER+2*STATE_SHORT_LEN_30MS];
       float *tmp, numerator[1+LPC_FILTERORDER]; 
       float foutbuf[LPC_FILTERORDER+2*STATE_SHORT_LEN_30MS], *fout;
       int k;
       float qmax, scal;
       
       /* initialization of buffers and filter coefficients */
   
       memset(tmpbuf, 0, LPC_FILTERORDER*sizeof(float));
       memset(foutbuf, 0, LPC_FILTERORDER*sizeof(float));
       for (k=0; k<LPC_FILTERORDER; k++) {
           numerator[k]=syntDenum[LPC_FILTERORDER-k];
       }
       numerator[LPC_FILTERORDER]=syntDenum[0];
       tmp = &tmpbuf[LPC_FILTERORDER];
       fout = &foutbuf[LPC_FILTERORDER];
   
       /* circular convolution with the all-pass filter */
       
       memcpy(tmp, residual, len*sizeof(float));
       memset(tmp+len, 0, len*sizeof(float));
       ZeroPoleFilter(tmp, numerator, syntDenum, 2*len, 
           LPC_FILTERORDER, fout);
       for (k=0; k<len; k++) {
           fout[k] += fout[k+len];
       }   
           
       /* identification of the maximum amplitude value */
       
       maxVal = fout[0];
   
   
       for (k=1; k<len; k++) {
           
           if (fout[k]*fout[k] > maxVal*maxVal){
               maxVal = fout[k];
           }
       }
       maxVal=(float)fabs(maxVal);
           
       /* encoding of the maximum amplitude value */
       
       if (maxVal < 10.0) {
           maxVal = 10.0;
       }
       maxVal = (float)log10(maxVal);
       sort_sq(&dtmp, idxForMax, maxVal, state_frgqTbl, 64);
   
       /* decoding of the maximum amplitude representation value,
          and corresponding scaling of start state */
   
       maxVal=state_frgqTbl[*idxForMax];
       qmax = (float)pow(10,maxVal);
       scal = (float)(4.5)/qmax;
       for (k=0; k<len; k++){
           fout[k] *= scal;
       }
   
       /* predictive noise shaping encoding of scaled start state */
   
       AbsQuantW(iLBCenc_inst, fout,syntDenum, 
           weightDenum,idxVec, len, state_first);
   }