g729ev_main_decod.c

最新的ITU-T的宽带语音编解码标准G.729.1,是对原先的G.729的最好的调整.码流输出速率可以进行自适应调整.满足未来通信要求.希望对大家有所帮助.

      /* update memory of A(z) and t0_first */
      G729EV_G729_Copy(BfAq, decstat->mem_Az, 4 * G729EV_G729_MP1);
      FOR(i = 0; i < 4; i++)
      {
        decstat->mem_t0[i] = shr(add(pitch_buf[i], G729EV_FEC_QPIT2), G729EV_FEC_SQPIT);
#if(WMOPS)
        move16();
#endif
      }
    }

#if(WMOPS)
    test();
    test();
#endif
    IF((sub(clas, G729EV_FEC_SIN_ONSET) == 0) && (sub(rate, 14000) >= 0) && (ind_fer[2] > 0))
    {
      if (sub(rate, 16000) < 0)
      {
        /* Use reconstruct energy information when not present in bitstream */
        L_enr_q = decstat->decStG729.Lenr_old;
#if(WMOPS)
        move16();
#endif
      }

      IF(sub(decstat->decStG729.bfi_cnt, 1) == 0)
      {
        G729EV_FEC_mod_adapt_codebook(decstat->decStG729.old_exc, ind_fer[2], pitch_buf, L_enr_q,
                                      BfAq + 3 * G729EV_G729_MP1);
      }
      ELSE
      {
        G729EV_FEC_mod_adapt_codebook(decstat->decStG729.old_exc, ind_fer[2], pitch_buf, L_enr_q,
                                      decstat->mem_Az + 3 * G729EV_G729_MP1);
      }
    }

    G729EV_G729_Copy(decstat->decStG729.mem_syn, mem_syntmp, G729EV_G729_M);
    decstat->decStG729.lp_gainc = (Word16) 0;
    decstat->decStG729.lp_gainp = (Word16) 0;
    decstat->decStG729.i_subfr_cnt = (Word16) 0;

#if(WMOPS)
    move16();
    move16();
    move16();
#endif


    /**************************************************************
     * Decoding of lower band : 8k core and 12k enhancement layer *
     **************************************************************/

#if(WMOPS)
    move16();
#endif
    j = (Word16) 0;
    FOR(i_frame = 0; i_frame < G729EV_MAIN_L_FRAME2; i_frame += G729EV_G729_L_FRAME)
    {
      /* get synthesis of G729/12k decoder (without postfilter) */
      G729EV_CELP2S_decoder(&decstat->decStG729, coder_param_ptr, rate, j, &nb_celp_param,
                            &BfAq[j * 2 * G729EV_G729_MP1], &coreExc[i_frame], &extExc[i_frame],
                            pitch_buf, clas, bfi);

      j = add(j, 1);

      /* update bit counter */
      IF(sub(rate, 12000) >= 0)
      {
        nb_bits_used = add(nb_bits_used, 120);
      }
      ELSE
      {
        nb_bits_used = add(nb_bits_used, 80);
      }

      /* update pointer to coder parameters offset */
      coder_param_ptr += G729EV_G729_PRM_SIZE_MAX;
    }

    /* number of bits lefts for decoding after CELP decoding */
    nb_bits_left = sub(nb_bits_left, nb_bits_used);

    G729EV_G729_syn(coreExc, extExc, decstat->decStG729.old_exc, BfAq, celp_output, decstat->decStG729.mem_syn,
                    decstat->decStG729.rate);

    /* if clas is not tranmist */
    IF(sub(rate, 12000) < 0)
    {
      G729EV_FEC_clas_dec(&clas, pitch_buf, decstat->lastgood, celp_output, decstat->synth_buf,
                          &(decstat->lp_ener_FER));
    }

    G729EV_FEC_pit_updt(clas, pitch_buf, decstat->lastgood, &(decstat->decStG729.upd_cnt),
                        &(decstat->decStG729.old_fpitch), decstat->decStG729.fpitch);

    G729EV_FEC_scale_syn(nb_bits_left, clas, decstat->lastgood, celp_output, pitch_buf, L_enr_q,
                         decstat->prev_bfi, BfAq, &(decstat->old_enrLP), mem_syntmp, coreExc,
                         decstat->decStG729.Lenr_old, decstat->decStG729.old_exc, decstat->decStG729.mem_syn,
                         decstat->decStG729.bfi_cnt);

    /***************************************************
    * Decoding of higher band : 14k enhancement layer *
    ***************************************************/

    IF(sub(rate, 14000) >= 0)
    {
      /* decode TDBWE parameters */
      G729EV_TDBWE_dequantization(coder_param_ptr, parameters_tdbwe);
      G729EV_TDBWE_decoder(&decstat->tdbwe, &nb_celp_param, output_hiTdbwe, parameters_tdbwe);

      /* copy TDBWE parameters for FEC */
      G729EV_G729_Copy(parameters_tdbwe, decstat->prev_parameters_tdbwe, G729EV_TDBWE_NB_PARAMETERS);
      FOR(i = 0; i < G729EV_MAIN_NB_SUBFR; i++)
      {
        decstat->prev_nb_celp_param.t0[i] = nb_celp_param.t0[i];
        decstat->prev_nb_celp_param.t0_frac[i] = nb_celp_param.t0_frac[i];
        decstat->prev_nb_celp_param.power_fix[i] = nb_celp_param.power_fix[i];
        decstat->prev_nb_celp_param.power_ltp[i] = nb_celp_param.power_ltp[i];
#if(WMOPS)
        move16();
        move16();
        move16();
        move16();
#endif
      }

      /* update bits counter and number of bits left */
      nb_bits_used = add(nb_bits_used, 40);
      nb_bits_left = sub(nb_bits_left, 40);

      /* update pointer to coder parameters offset */
      coder_param_ptr += 6;

      /* postprocessing of higher band (3 kHz low-pass filter) */
      IF(decstat->low_delay > 0)
      {
        G729EV_MAIN_lp3k(&decstat->mem_lp3k, output_hiTdbwe, G729EV_MAIN_L_FRAME2);
        G729EV_G729_Set_zero(output_hiTdbwe, G729EV_MAIN_L_FRAME2);
      }
    }
    ELSE
    {
      /* if rate < 14000 TDBWE output is forced to 0 */
      G729EV_G729_Set_zero(output_hiTdbwe, G729EV_MAIN_L_FRAME2);
    }

    /*************************************************************
    * Decoding of full-band spectrum: 16-32k enhancement layers *
    *************************************************************/

    IF(decstat->low_delay == 0)
    {
      /* update maximum number of bits for encoding based on previous layers */
      nb_bits_max = sub(nb_bits_max, nb_bits_used);

      /* decode TDAC module - get norm_MDCT value */
      norm_MDCT = *coder_param_ptr;
#if(WMOPS)
      move16();
#endif
      /* compute MDCT of the TDBWE synthesis */
      norm_local = G729EV_TDAC_mdct(decstat->mem_mdct_hi, output_hiTdbwe, yt_hi, -15);
      G729EV_TDAC_mdct(decstat->mem_mdct_hi, output_hiTdbwe, yt_hi, norm_local);

      /* Update nb_bits (read FEC (5 bits) + norm_shift (4 bits)) */
      nb_bits_max = sub(nb_bits_max, 9);
      IF(sub(rate, 16000) >= 0)
      {
        nb_bits_left = sub(nb_bits_left, 9);
      }
      ELSE
      {
        nb_bits_left = (Word16) 0;
        norm_MDCT = norm_local;
#if(WMOPS)
        move16();
        move16();
#endif
      }

      /* rescale yt_hi to be norm_shift compliant */
      diff_norm = sub(norm_MDCT, norm_local);
      FOR(i = 0; i < G729EV_MAIN_L_FRAME2; i++)
      {
        yt_hi[i] = shl(yt_hi[i], diff_norm);
#if(WMOPS)
        move16();
#endif
      }

      /* TDAC decoder */
      G729EV_TDAC_decoder(&itu_192_bitstream[289], (Word16) nb_bits_left, (Word16) nb_bits_max,
                          yt_hi, yq_lo, yq_hi, norm_MDCT);

      /* post-process reconstructed higher-band spectrum */
      G729EV_TDAC_PostProcess(yq_hi, nb_bits_to_decode);

      /* inverse MDCT to obtain
         - reconstructed difference signal in lower band
         - reconstructed signal in higher band */
      G729EV_TDAC_inv_mdct(diff_q, yq_lo, decstat->mem_inv_mdct_lo, norm_MDCT);
      G729EV_TDAC_inv_mdct(output_hi, yq_hi, decstat->mem_inv_mdct_hi, norm_MDCT);

      /* compute false alarm zones for pre/post-echo reduction */
      G729EV_MAIN_PreechoFalseAlarm(diff_q, decstat->mem_inv_mdct_lo, &decstat->max_prev_lo,  
                                    &begin_index_low, &end_index_low);
      G729EV_MAIN_PreechoFalseAlarm(output_hi, decstat->mem_inv_mdct_hi, &decstat->max_prev_hi,
                                    &begin_index_high, &end_index_high);

      /* apply inverse weighting filter to the reconstructed lower-band difference signal */
      G729EV_MAIN_inverse_weighting_filter(decstat->mem_Az, decstat->mem_invWz_in, decstat->mem_invwsp, diff_q);

      /* signal upsampling */
      FOR(i = 0; i < G729EV_MAIN_L_FRAME2; i++)
      {
        decstat->old_celp_output[i] = shl(decstat->old_celp_output[i], 1);
#if(WMOPS)
        move16();
#endif
      }

      /* preecho reduction & add 12k output to reconstructed difference signal */
      G729EV_MAIN_envAdapt(output_lo, decstat->old_celp_output, diff_q, &decstat->vmlold,
                           output_hi, decstat->sTdbweOld, output_hi, &decstat->vmhold, (Word16) (rate > 14000),
                           begin_index_low, end_index_low, begin_index_high, end_index_high);
      FOR(j = 0; j < G729EV_MAIN_L_FRAME2; j++)
      {
        output_lo[j] = shr(output_lo[j], 1);
#if(WMOPS)
        move16();
#endif
      }

      /* update output for next frame */
      G729EV_G729_Copy(output_hiTdbwe, decstat->sTdbweOld, G729EV_MAIN_L_FRAME2);
      G729EV_G729_Copy(celp_output, decstat->old_celp_output, G729EV_MAIN_L_FRAME2);
    }
    ELSE
    {
      G729EV_G729_Copy(celp_output, output_lo, G729EV_MAIN_L_FRAME2);
      G729EV_G729_Copy(output_hiTdbwe, output_hi, G729EV_MAIN_L_FRAME2);
      G729EV_G729_Copy(celp_output, decstat->old_celp_output, G729EV_MAIN_L_FRAME2);
    }

    /********************************
     * Adapt bitrate switching gain *
     ********************************/

    /* count number of frames with same bandwidth */
    IF(sub(rate, 12000) <= 0)   /* 12 kbit/s */
    {
      nRcv_hi = (Word16) 1;
    }
    ELSE
    {
      nRcv_hi = (Word16) 0;
    }


#if(WMOPS)
    move16();
    test();
#endif
    IF((nRcv_hi == 0) && (decstat->prev_nRcv_hi == 0))
    {
      decstat->count_rcv = add(decstat->count_rcv, 1);
      if (sub(decstat->count_rcv, G729EV_MAIN_COUNT_RCV_MAX) > 0)
      {
        decstat->count_rcv = G729EV_MAIN_COUNT_RCV_MAX;
#if(WMOPS)
        move16();
#endif
      }
    }
    ELSE
    {
      IF(nRcv_hi != 0)
      {
#if(WMOPS)
        test();
        test();
        test();
#endif
        if ((decstat->first_frame != 0) ||
            (decstat->prev_nRcv_hi != 0) ||
            ((decstat->prev_nRcv_hi == 0) && (sub(decstat->count_rcv, G729EV_MAIN_COUNT_RCV_MAX) < 0)))
        {
          decstat->count_rcv = (Word16) 0;
#if(WMOPS)
          move16();
#endif
        }
      }
    }
    decstat->prev_nRcv_hi = nRcv_hi;
    decstat->first_frame = (Word16) 0;
#if(WMOPS)
    move16();
    move16();
#endif

    /*******************************
     * Postfiltering in lower-band *
     *******************************/

    /* set adaptive gamma parameters of postfilter */
    G729EV_MAIN_set_gamma(output_lo, decstat->tab_Th, rate, &ga1_post, &ga2_post);

    /* set post-filter input */
    pf_in = &pf_in_buffer[G729EV_G729_M_LPC];
#if(WMOPS)
    move16();
#endif
    G729EV_G729_Copy(decstat->mem_pf_in, &pf_in[-G729EV_G729_M_LPC], G729EV_G729_M_LPC);
    G729EV_G729_Copy(output_lo, pf_in, G729EV_MAIN_L_FRAME2);
    G729EV_G729_Copy(&output_lo[G729EV_MAIN_L_FRAME2 - G729EV_G729_M_LPC], decstat->mem_pf_in, G729EV_G729_M_LPC);

    /* postfilter */
    pfstat = &decstat->mem_pf;
    IF(decstat->low_delay == 0) ptr_Az = decstat->mem_Az;
    ELSE ptr_Az = nb_celp_param.Az;

#if(WMOPS)
    move16();
    move16();
#endif
    j = (Word16) 0;
#if(WMOPS)
    move16();
#endif
    FOR(i = 0; i < G729EV_MAIN_L_FRAME2; i += G729EV_G729_L_SUBFR)
    {
      IF(decstat->low_delay == 0) t0_first = decstat->mem_t0[(j / 2) * 2];
      ELSE t0_first = nb_celp_param.t0[(j / 2) * 2];
#if(WMOPS)
      move16();
#endif
      G729EV_CELP2S_Post(pfstat, t0_first, &pf_in[i], ptr_Az, &output_lo[i],
                         ga1_post, ga2_post, G729EV_MAIN_switching_gain[decstat->count_rcv],
                         decstat->decStG729.ftyp[(int) (j / 2)]);

      ptr_Az += G729EV_G729_MP1;
      j = add(j, 1);
    }

    IF(decstat->low_delay == 0)
    {
      /* update memory of A(z) and t0_first */
      G729EV_G729_Copy(nb_celp_param.Az, decstat->mem_Az, 4 * G729EV_G729_MP1);
      G729EV_G729_Copy(nb_celp_param.t0, decstat->mem_t0, 4);
    }