ilbc_decode.c

视频监控vc源代码.对于做视频系统的朋友们很有帮助

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

    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 "iLBC_decode.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) 
 *---------------------------------------------------------------*/

static 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 */

            memcpy(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 */

            memcpy(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 */