ilbc_decode.c

mediastreamer2是开源的网络传输媒体流的库

   /******************************************************************

       iLBC Speech Coder ANSI-C Source Code

       iLBC_decode.c

       Copyright (C) The Internet Society (2004).
       All Rights Reserved.

   ******************************************************************/

   #include <math.h>
   #include <stdlib.h>

   #include "iLBC_define.h"
   #include "StateConstructW.h"
   #include "LPCdecode.h"
   #include "iCBConstruct.h"
   #include "doCPLC.h"
   #include "helpfun.h"
   #include "constants.h"
   #include "packing.h"
   #include "string.h"
   #include "enhancer.h"
   #include "hpOutput.h"
   #include "syntFilter.h"

   /*----------------------------------------------------------------*
    *  Initiation of decoder instance.
    *---------------------------------------------------------------*/

   short initDecode(                   /* (o) Number of decoded
                                              samples */
       iLBC_Dec_Inst_t *iLBCdec_inst,  /* (i/o) Decoder instance */
       int mode,                       /* (i) frame size mode */
       int use_enhancer                /* (i) 1 to use enhancer
                                              0 to run without
                                                enhancer */
   ){
       int i;

       iLBCdec_inst->mode = mode;





       if (mode==30) {
           iLBCdec_inst->blockl = BLOCKL_30MS;
           iLBCdec_inst->nsub = NSUB_30MS;
           iLBCdec_inst->nasub = NASUB_30MS;
           iLBCdec_inst->lpc_n = LPC_N_30MS;
           iLBCdec_inst->no_of_bytes = NO_OF_BYTES_30MS;
           iLBCdec_inst->no_of_words = NO_OF_WORDS_30MS;
           iLBCdec_inst->state_short_len=STATE_SHORT_LEN_30MS;
           /* ULP init */
           iLBCdec_inst->ULP_inst=&ULP_30msTbl;
       }
       else if (mode==20) {
           iLBCdec_inst->blockl = BLOCKL_20MS;
           iLBCdec_inst->nsub = NSUB_20MS;
           iLBCdec_inst->nasub = NASUB_20MS;
           iLBCdec_inst->lpc_n = LPC_N_20MS;
           iLBCdec_inst->no_of_bytes = NO_OF_BYTES_20MS;
           iLBCdec_inst->no_of_words = NO_OF_WORDS_20MS;
           iLBCdec_inst->state_short_len=STATE_SHORT_LEN_20MS;
           /* ULP init */
           iLBCdec_inst->ULP_inst=&ULP_20msTbl;
       }
       else {
           exit(2);
       }

       memset(iLBCdec_inst->syntMem, 0,
           LPC_FILTERORDER*sizeof(float));
       memcpy((*iLBCdec_inst).lsfdeqold, lsfmeanTbl,
           LPC_FILTERORDER*sizeof(float));

       memset(iLBCdec_inst->old_syntdenum, 0,
           ((LPC_FILTERORDER + 1)*NSUB_MAX)*sizeof(float));
       for (i=0; i<NSUB_MAX; i++)
           iLBCdec_inst->old_syntdenum[i*(LPC_FILTERORDER+1)]=1.0;

       iLBCdec_inst->last_lag = 20;

       iLBCdec_inst->prevLag = 120;
       iLBCdec_inst->per = 0.0;
       iLBCdec_inst->consPLICount = 0;
       iLBCdec_inst->prevPLI = 0;
       iLBCdec_inst->prevLpc[0] = 1.0;
       memset(iLBCdec_inst->prevLpc+1,0,
           LPC_FILTERORDER*sizeof(float));
       memset(iLBCdec_inst->prevResidual, 0, BLOCKL_MAX*sizeof(float));
       iLBCdec_inst->seed=777;






       memset(iLBCdec_inst->hpomem, 0, 4*sizeof(float));

       iLBCdec_inst->use_enhancer = use_enhancer;
       memset(iLBCdec_inst->enh_buf, 0, ENH_BUFL*sizeof(float));
       for (i=0;i<ENH_NBLOCKS_TOT;i++)
           iLBCdec_inst->enh_period[i]=(float)40.0;

       iLBCdec_inst->prev_enh_pl = 0;

       return (iLBCdec_inst->blockl);
   }

   /*----------------------------------------------------------------*
    *  frame residual decoder function (subrutine to iLBC_decode)
    *---------------------------------------------------------------*/

   void Decode(
       iLBC_Dec_Inst_t *iLBCdec_inst,  /* (i/o) the decoder state
                                                structure */
       float *decresidual,             /* (o) decoded residual frame */
       int start,                      /* (i) location of start
                                              state */
       int idxForMax,                  /* (i) codebook index for the
                                              maximum value */
       int *idxVec,                /* (i) codebook indexes for the
                                              samples  in the start
                                              state */
       float *syntdenum,               /* (i) the decoded synthesis
                                              filter coefficients */
       int *cb_index,                  /* (i) the indexes for the
                                              adaptive codebook */
       int *gain_index,            /* (i) the indexes for the
                                              corresponding gains */
       int *extra_cb_index,        /* (i) the indexes for the
                                              adaptive codebook part
                                              of start state */
       int *extra_gain_index,          /* (i) the indexes for the
                                              corresponding gains */
       int state_first                 /* (i) 1 if non adaptive part
                                              of start state comes
                                              first 0 if that part
                                              comes last */
   ){
       float reverseDecresidual[BLOCKL_MAX], mem[CB_MEML];
       int k, meml_gotten, Nfor, Nback, i;
       int diff, start_pos;
       int subcount, subframe;






       diff = STATE_LEN - iLBCdec_inst->state_short_len;

       if (state_first == 1) {
           start_pos = (start-1)*SUBL;
       } else {
           start_pos = (start-1)*SUBL + diff;
       }

       /* decode scalar part of start state */

       StateConstructW(idxForMax, idxVec,
           &syntdenum[(start-1)*(LPC_FILTERORDER+1)],
           &decresidual[start_pos], iLBCdec_inst->state_short_len);


       if (state_first) { /* put adaptive part in the end */

           /* setup memory */

           memset(mem, 0,
               (CB_MEML-iLBCdec_inst->state_short_len)*sizeof(float));
           memcpy(mem+CB_MEML-iLBCdec_inst->state_short_len,
               decresidual+start_pos,
               iLBCdec_inst->state_short_len*sizeof(float));

           /* construct decoded vector */

           iCBConstruct(
               &decresidual[start_pos+iLBCdec_inst->state_short_len],
               extra_cb_index, extra_gain_index, mem+CB_MEML-stMemLTbl,
               stMemLTbl, diff, CB_NSTAGES);

       }
       else {/* put adaptive part in the beginning */

           /* create reversed vectors for prediction */

           for (k=0; k<diff; k++) {
               reverseDecresidual[k] =
                   decresidual[(start+1)*SUBL-1-
                           (k+iLBCdec_inst->state_short_len)];
           }

           /* setup memory */

           meml_gotten = iLBCdec_inst->state_short_len;
           for (k=0; k<meml_gotten; k++){
               mem[CB_MEML-1-k] = decresidual[start_pos + k];





           }
           memset(mem, 0, (CB_MEML-k)*sizeof(float));

           /* construct decoded vector */

           iCBConstruct(reverseDecresidual, extra_cb_index,
               extra_gain_index, mem+CB_MEML-stMemLTbl, stMemLTbl,
               diff, CB_NSTAGES);

           /* get decoded residual from reversed vector */

           for (k=0; k<diff; k++) {
               decresidual[start_pos-1-k] = reverseDecresidual[k];
           }
       }

       /* counter for predicted sub-frames */

       subcount=0;

       /* forward prediction of sub-frames */

       Nfor = iLBCdec_inst->nsub-start-1;

       if ( Nfor > 0 ){

           /* setup memory */

           memset(mem, 0, (CB_MEML-STATE_LEN)*sizeof(float));
           memcpy(mem+CB_MEML-STATE_LEN, decresidual+(start-1)*SUBL,
               STATE_LEN*sizeof(float));

           /* loop over sub-frames to encode */

           for (subframe=0; subframe<Nfor; subframe++) {

               /* construct decoded vector */

               iCBConstruct(&decresidual[(start+1+subframe)*SUBL],
                   cb_index+subcount*CB_NSTAGES,
                   gain_index+subcount*CB_NSTAGES,
                   mem+CB_MEML-memLfTbl[subcount],
                   memLfTbl[subcount], SUBL, CB_NSTAGES);

               /* update memory */

               memmove(mem, mem+SUBL, (CB_MEML-SUBL)*sizeof(float));
               memcpy(mem+CB_MEML-SUBL,





                   &decresidual[(start+1+subframe)*SUBL],
                   SUBL*sizeof(float));

               subcount++;

           }

       }

       /* backward prediction of sub-frames */

       Nback = start-1;

       if ( Nback > 0 ) {

           /* setup memory */

           meml_gotten = SUBL*(iLBCdec_inst->nsub+1-start);

           if ( meml_gotten > CB_MEML ) {
               meml_gotten=CB_MEML;
           }
           for (k=0; k<meml_gotten; k++) {
               mem[CB_MEML-1-k] = decresidual[(start-1)*SUBL + k];
           }
           memset(mem, 0, (CB_MEML-k)*sizeof(float));

           /* loop over subframes to decode */

           for (subframe=0; subframe<Nback; subframe++) {

               /* construct decoded vector */

               iCBConstruct(&reverseDecresidual[subframe*SUBL],
                   cb_index+subcount*CB_NSTAGES,
                   gain_index+subcount*CB_NSTAGES,
                   mem+CB_MEML-memLfTbl[subcount], memLfTbl[subcount],
                   SUBL, CB_NSTAGES);

               /* update memory */

               memmove(mem, mem+SUBL, (CB_MEML-SUBL)*sizeof(float));
               memcpy(mem+CB_MEML-SUBL,
                   &reverseDecresidual[subframe*SUBL],
                   SUBL*sizeof(float));

               subcount++;
           }





           /* get decoded residual from reversed vector */

           for (i=0; i<SUBL*Nback; i++)
               decresidual[SUBL*Nback - i - 1] =
               reverseDecresidual[i];
       }
   }

   /*----------------------------------------------------------------*
    *  main decoder function
    *---------------------------------------------------------------*/

   void iLBC_decode(
       float *decblock,            /* (o) decoded signal block */