ilbc_decode.c

Asterisk-1.4.4最新内核源代码

    unsigned char *bytes,           /* (i) encoded signal bits */
    iLBC_Dec_Inst_t *iLBCdec_inst,  /* (i/o) the decoder state 
                                             structure */
    int mode                    /* (i) 0: bad packet, PLC, 
                                           1: normal */
){
    float data[BLOCKL_MAX];
    float lsfdeq[LPC_FILTERORDER*LPC_N_MAX];
    float PLCresidual[BLOCKL_MAX], PLClpc[LPC_FILTERORDER + 1];
    float zeros[BLOCKL_MAX], one[LPC_FILTERORDER + 1];
    int k, i, start, idxForMax, pos, lastpart, ulp;
    int lag, ilag;
    float cc, maxcc;
    int idxVec[STATE_LEN];
    int check;
    int gain_index[NASUB_MAX*CB_NSTAGES], 
        extra_gain_index[CB_NSTAGES];
    int cb_index[CB_NSTAGES*NASUB_MAX], extra_cb_index[CB_NSTAGES];
    int lsf_i[LSF_NSPLIT*LPC_N_MAX];
    int state_first;


    int last_bit;
    unsigned char *pbytes;
    float weightdenum[(LPC_FILTERORDER + 1)*NSUB_MAX];
    int order_plus_one;
    float syntdenum[NSUB_MAX*(LPC_FILTERORDER+1)]; 
    float decresidual[BLOCKL_MAX];
    
    if (mode>0) { /* the data are good */

        /* decode data */
        
        pbytes=bytes;
        pos=0;

        /* Set everything to zero before decoding */

        for (k=0; k<LSF_NSPLIT*LPC_N_MAX; k++) {
            lsf_i[k]=0;
        }
        start=0;
        state_first=0;
        idxForMax=0;
        for (k=0; k<iLBCdec_inst->state_short_len; k++) {
            idxVec[k]=0;
        }
        for (k=0; k<CB_NSTAGES; k++) {
            extra_cb_index[k]=0;
        }
        for (k=0; k<CB_NSTAGES; k++) {
            extra_gain_index[k]=0;
        }
        for (i=0; i<iLBCdec_inst->nasub; i++) {
            for (k=0; k<CB_NSTAGES; k++) {
                cb_index[i*CB_NSTAGES+k]=0;
            }
        }
        for (i=0; i<iLBCdec_inst->nasub; i++) {
            for (k=0; k<CB_NSTAGES; k++) {
                gain_index[i*CB_NSTAGES+k]=0;
            }
        }

        /* loop over ULP classes */

        for (ulp=0; ulp<3; ulp++) {
        
            /* LSF */
            for (k=0; k<LSF_NSPLIT*iLBCdec_inst->lpc_n; k++){
                unpack( &pbytes, &lastpart, 
                    iLBCdec_inst->ULP_inst->lsf_bits[k][ulp], &pos);
                packcombine(&lsf_i[k], lastpart,
                    iLBCdec_inst->ULP_inst->lsf_bits[k][ulp]);
            }



            /* Start block info */

            unpack( &pbytes, &lastpart, 
                iLBCdec_inst->ULP_inst->start_bits[ulp], &pos);
            packcombine(&start, lastpart, 
                iLBCdec_inst->ULP_inst->start_bits[ulp]);

            unpack( &pbytes, &lastpart, 
                iLBCdec_inst->ULP_inst->startfirst_bits[ulp], &pos);
            packcombine(&state_first, lastpart,
                iLBCdec_inst->ULP_inst->startfirst_bits[ulp]);

            unpack( &pbytes, &lastpart, 
                iLBCdec_inst->ULP_inst->scale_bits[ulp], &pos);
            packcombine(&idxForMax, lastpart, 
                iLBCdec_inst->ULP_inst->scale_bits[ulp]);

            for (k=0; k<iLBCdec_inst->state_short_len; k++) {
                unpack( &pbytes, &lastpart, 
                    iLBCdec_inst->ULP_inst->state_bits[ulp], &pos);
                packcombine(idxVec+k, lastpart,
                    iLBCdec_inst->ULP_inst->state_bits[ulp]);
            }

            /* 23/22 (20ms/30ms) sample block */

            for (k=0; k<CB_NSTAGES; k++) {
                unpack( &pbytes, &lastpart, 
                    iLBCdec_inst->ULP_inst->extra_cb_index[k][ulp], 
                    &pos);
                packcombine(extra_cb_index+k, lastpart, 
                    iLBCdec_inst->ULP_inst->extra_cb_index[k][ulp]);
            }
            for (k=0; k<CB_NSTAGES; k++) {
                unpack( &pbytes, &lastpart, 
                    iLBCdec_inst->ULP_inst->extra_cb_gain[k][ulp], 
                    &pos);
                packcombine(extra_gain_index+k, lastpart,
                    iLBCdec_inst->ULP_inst->extra_cb_gain[k][ulp]);
            }
                
            /* The two/four (20ms/30ms) 40 sample sub-blocks */

            for (i=0; i<iLBCdec_inst->nasub; i++) {
                for (k=0; k<CB_NSTAGES; k++) {
                    unpack( &pbytes, &lastpart, 
                    iLBCdec_inst->ULP_inst->cb_index[i][k][ulp], 
                        &pos);
                    packcombine(cb_index+i*CB_NSTAGES+k, lastpart, 
                    iLBCdec_inst->ULP_inst->cb_index[i][k][ulp]);
                }
            }
            
            for (i=0; i<iLBCdec_inst->nasub; i++) {


                for (k=0; k<CB_NSTAGES; k++) {
                    unpack( &pbytes, &lastpart, 

                    iLBCdec_inst->ULP_inst->cb_gain[i][k][ulp], 
                        &pos);
                    packcombine(gain_index+i*CB_NSTAGES+k, lastpart,
                        iLBCdec_inst->ULP_inst->cb_gain[i][k][ulp]);
                }
            }
        }
        /* Extract last bit. If it is 1 this indicates an 
           empty/lost frame */
        unpack( &pbytes, &last_bit, 1, &pos);

        /* Check for bit errors or empty/lost frames */
        if (start<1)
            mode = 0;
        if (iLBCdec_inst->mode==20 && start>3)
            mode = 0;
        if (iLBCdec_inst->mode==30 && start>5)
            mode = 0;
        if (last_bit==1)
            mode = 0;

        if (mode==1) { /* No bit errors was detected, 
                          continue decoding */
                
            /* adjust index */
            index_conv_dec(cb_index);

            /* decode the lsf */

            SimplelsfDEQ(lsfdeq, lsf_i, iLBCdec_inst->lpc_n);
            check=LSF_check(lsfdeq, LPC_FILTERORDER, 
                iLBCdec_inst->lpc_n);
            DecoderInterpolateLSF(syntdenum, weightdenum, 
                lsfdeq, LPC_FILTERORDER, iLBCdec_inst);
        
            Decode(iLBCdec_inst, decresidual, start, idxForMax, 
                idxVec, syntdenum, cb_index, gain_index, 
                extra_cb_index, extra_gain_index, 
                state_first);

            /* preparing the plc for a future loss! */

            doThePLC(PLCresidual, PLClpc, 0, decresidual, 
                syntdenum + 
                (LPC_FILTERORDER + 1)*(iLBCdec_inst->nsub - 1),
                (*iLBCdec_inst).last_lag, iLBCdec_inst);

        
            memcpy(decresidual, PLCresidual, 
                iLBCdec_inst->blockl*sizeof(float));
        }


        
    }
    
    if (mode == 0) {
        /* the data is bad (either a PLC call
         * was made or a severe bit error was detected)
         */
        
        /* packet loss conceal */

        memset(zeros, 0, BLOCKL_MAX*sizeof(float));
        
        one[0] = 1;
        memset(one+1, 0, LPC_FILTERORDER*sizeof(float));
        
        start=0;
        
        doThePLC(PLCresidual, PLClpc, 1, zeros, one,
            (*iLBCdec_inst).last_lag, iLBCdec_inst);
        memcpy(decresidual, PLCresidual, 
            iLBCdec_inst->blockl*sizeof(float));
        
        order_plus_one = LPC_FILTERORDER + 1;
        for (i = 0; i < iLBCdec_inst->nsub; i++) {
            memcpy(syntdenum+(i*order_plus_one), PLClpc, 
                order_plus_one*sizeof(float));
        }
    }

    if (iLBCdec_inst->use_enhancer == 1) {

        /* post filtering */
        
        iLBCdec_inst->last_lag = 
            enhancerInterface(data, decresidual, iLBCdec_inst);

        /* synthesis filtering */
        
        if (iLBCdec_inst->mode==20) {
            /* Enhancer has 40 samples delay */
            i=0;
            syntFilter(data + i*SUBL, 
                iLBCdec_inst->old_syntdenum + 
                (i+iLBCdec_inst->nsub-1)*(LPC_FILTERORDER+1), 
                SUBL, iLBCdec_inst->syntMem);
            for (i=1; i < iLBCdec_inst->nsub; i++) {
                syntFilter(data + i*SUBL, 
                    syntdenum + (i-1)*(LPC_FILTERORDER+1), 
                    SUBL, iLBCdec_inst->syntMem);
            }
        } else if (iLBCdec_inst->mode==30) {
            /* Enhancer has 80 samples delay */
            for (i=0; i < 2; i++) {
                syntFilter(data + i*SUBL, 


                    iLBCdec_inst->old_syntdenum + 
                    (i+iLBCdec_inst->nsub-2)*(LPC_FILTERORDER+1),
                    SUBL, iLBCdec_inst->syntMem);
            }
            for (i=2; i < iLBCdec_inst->nsub; i++) {
                syntFilter(data + i*SUBL, 
                    syntdenum + (i-2)*(LPC_FILTERORDER+1), SUBL,
                    iLBCdec_inst->syntMem);
            }
        }

    } else {

        /* Find last lag */
        lag = 20;
        maxcc = xCorrCoef(&decresidual[BLOCKL_MAX-ENH_BLOCKL], 
            &decresidual[BLOCKL_MAX-ENH_BLOCKL-lag], ENH_BLOCKL);
        
        for (ilag=21; ilag<120; ilag++) {
            cc = xCorrCoef(&decresidual[BLOCKL_MAX-ENH_BLOCKL], 
                &decresidual[BLOCKL_MAX-ENH_BLOCKL-ilag], 
                ENH_BLOCKL);
        
            if (cc > maxcc) {
                maxcc = cc;
                lag = ilag;
            }
        }
        iLBCdec_inst->last_lag = lag;

        /* copy data and run synthesis filter */

        memcpy(data, decresidual, 
            iLBCdec_inst->blockl*sizeof(float));
        for (i=0; i < iLBCdec_inst->nsub; i++) {
            syntFilter(data + i*SUBL, 
                syntdenum + i*(LPC_FILTERORDER+1), SUBL, 
                iLBCdec_inst->syntMem);
        }
    }

    /* high pass filtering on output if desired, otherwise 
       copy to out */

    hpOutput(data, iLBCdec_inst->blockl, 
                decblock,iLBCdec_inst->hpomem);

    /* memcpy(decblock,data,iLBCdec_inst->blockl*sizeof(float));*/

    memcpy(iLBCdec_inst->old_syntdenum, syntdenum, 

        iLBCdec_inst->nsub*(LPC_FILTERORDER+1)*sizeof(float));

    iLBCdec_inst->prev_enh_pl=0;



    if (mode==0) { /* PLC was used */
        iLBCdec_inst->prev_enh_pl=1;
    }
}