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.

    /**************************
     * Postprocess lower band *
     **************************/

    /* G729 postprocessing */
    G729EV_G729_Copy(output_lo, pst_in, G729EV_MAIN_L_FRAME2);

    G729EV_MAIN_iir2(&decstat->mem_postpro, output_lo, G729EV_MAIN_L_FRAME2, G729EV_MAIN_b100, G729EV_MAIN_a100, 0);

    /* cross-fade output_lo and pst_out if bit rate switching */
    IF(sub(rate, 12000) <= 0)   /* 12 kbit/s */
    {
      /* narrowband output (8, 12k modes) */
      /* cross-fade two narrowband outputs (without or with postprocessing) if previous decoded frame was not postprocessed */
      IF(decstat->mem_postflag == 0)
      {
        tmp16 = (Word16) 102;
#if(WMOPS)
        move16();
#endif
        FOR(i = 0; i < G729EV_MAIN_L_FRAME2; i += 1)
        {
          /* output_lo[i] = (REAL)( i/(len-1.0)*output_lo[i]+ (1-(REAL)i/(len-1.0))*pst_in[i] ); */
          /* output_lo and pst_in both in Q14 */
          Ltmp = L_mult(tmp16, output_lo[i]);
          Ltmp = L_mac(Ltmp, pst_in[i], sub(16384, tmp16));
          output_lo[i] = round(L_shl(Ltmp, 2));
#if(WMOPS)
          move16();
#endif
          tmp16 = add(tmp16, 102);
        }
      }
      ELSE
      {
        /* put output_lo in Q15 */
        FOR(i = 0; i < G729EV_MAIN_L_FRAME2; i++)
        {
          output_lo[i] = shl(output_lo[i], 1);
#if(WMOPS)
          move16();
#endif
        }
      }

      /* declare this frame as postprocessed */
      decstat->mem_postflag = (Word16) 1;
#if(WMOPS)
      move16();
#endif
    }
    ELSE
    {
      /* wideband output (modes >= 14k) */
      /* cross-fade two narrowband outputs (without or with postprocessing) if previous decoded frame was postprocessed
         otherwise copy non postprocessed output */
      IF(decstat->mem_postflag == 1)
      {
        tmp16 = (Word16) 102;
#if(WMOPS)
        move16();
#endif
        FOR(i = 0; i < G729EV_MAIN_L_FRAME2; i += 1)
        {
          /*output_lo[i] = (REAL)( i/(len-1.0)*pst_in[i]+ (1-(REAL)i/(len-1.0))*output_lo[i] ); */
          Ltmp = L_mult(tmp16, pst_in[i]);
          Ltmp = L_mac(Ltmp, output_lo[i], sub(16384, tmp16));
          output_lo[i] = round(L_shl(Ltmp, 2));
#if(WMOPS)
          move16();
#endif
          tmp16 = add(tmp16, 102);
        }
      }
      ELSE
      {
        /* put output_lo in Q15 */
        FOR(i = 0; i < G729EV_MAIN_L_FRAME2; i++)
        {
          output_lo[i] = shl(pst_in[i], 1);
#if(WMOPS)
          move16();
#endif
        }
      }
      decstat->mem_postflag = (Word16) 0;
#if(WMOPS)
      move16();
#endif
    }

    /*****************************************************************
    * Fold higher band and combine bands by QMF synthesis filterbank *
    ******************************************************************/

    IF(decstat->f8 == 0)
    {                           /* test if 8kHz sampled output */
      /* mirror signal prior to filterbank synthesis */
      G729EV_MAIN_QMF_mirror(output_hi, G729EV_MAIN_L_FRAME2);

      /* synthesis filterbank */
      G729EV_MAIN_QMF_syn(&decstat->qmf_syn, output_lo, output_hi, tabout, G729EV_MAIN_L_FRAME2,
                          G729EV_MAIN_switching_gain[decstat->count_rcv]);
    }
    ELSE
    {
      G729EV_G729_Copy(output_lo, tabout, G729EV_MAIN_L_FRAME2);
    }

    /*******************
     * Update memories *
     *******************/

    decstat->plast_good = decstat->lastgood;
    decstat->lastgood = clas;
    decstat->decStG729.bfi_cnt = (Word16) 0;
    decstat->prev_rate = rate;
#if(WMOPS)
    move16();
    move16();
    move16();
    move16();
#endif

  }
  ELSE
  {

    /************************************************ FEC (bfi=1) ***********************************/


    /***********************
     * Decode 8-12k layers *
     ***********************/
#if(WMOPS)
    test();
#endif
    IF((decstat->decStG729.bfi_cnt > 0) || (decstat->low_delay > 0))
    {
      /* FEC decoder */
      G729EV_FEC_dec_bf(parm_FEC, decstat->old_celp_output, BfAq, bfi,
                        &(decstat->lastgood), pitch_buf, decstat->old_enrLP,
                        decstat->decStG729.old_exc, &(decstat->decStG729), clas, ind_fer[2]);

      /* Update to be done before decoding a good frame */
      FerPitch = shr(add(pitch_buf[0], G729EV_FEC_QPIT2), G729EV_FEC_SQPIT);
      if (sub(FerPitch, G729EV_G729_PIT_MIN) < 0)
      {
        FerPitch = G729EV_G729_PIT_MIN;
#if(WMOPS)
        move16();
#endif
      }
      if (sub(FerPitch, G729EV_G729_PIT_MAX) > 0)
      {
        FerPitch = G729EV_G729_PIT_MAX;
#if(WMOPS)
        move16();
#endif
      }

      /* taming */
      G729EV_G729_UpdateMemTam(&decstat->decStG729, decstat->decStG729.lp_gainp, FerPitch);
      G729EV_G729_UpdateMemTam(&decstat->decStG729, decstat->decStG729.lp_gainp, FerPitch);

      /* 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(decstat->low_delay == 0)
    {
      ind = sub(G729EV_TDAC_L_WIN2, 1);
      FOR(i = 0; i < G729EV_TDAC_L_WIN2; i++)
      {
        output_lo[i] =
            mac_r(L_mult(decstat->old_celp_output[i], 32767), decstat->mem_inv_mdct_lo[i], G729EV_TDAC_h[ind]);
        ind = sub(ind, 1);
        decstat->mem_inv_mdct_lo[i] = (Word16) 0;
#if(WMOPS)
        move16();
        move16();
#endif
      }
    }
    ELSE
    {
      G729EV_G729_Copy(decstat->old_celp_output, output_lo, G729EV_MAIN_L_FRAME2);
    }

    /************************************
     * Decode 14-32k enhancement layers *
     ************************************/

    /* TDBWE decoder in FEC */
    IF(sub(decstat->prev_rate, 14000) >= 0) /* 14 kbit/s */
    {
      IF(sub(decstat->decStG729.bfi_cnt, 2) > 0)
      {
        FOR(i = 0; i < G729EV_TDBWE_NB_SUBFRAMES; i++) {
          tmp16 = sub(decstat->prev_parameters_tdbwe[i], 1024); /* -3 dB */
          IF( sub(tmp16,(Word16)-1700)<0 ) {
            tmp16 = (Word16) -1700;
          }
          decstat->prev_parameters_tdbwe[i] = tmp16;
        }
        FOR(i = 0; i < G729EV_TDBWE_NB_SUBBANDS; i++) {
          tmp16 = sub(decstat->prev_parameters_tdbwe[i+G729EV_TDBWE_PAROFS_FREQ_ENVELOPE], 1024); /* -3 dB */
          IF( sub(tmp16,(Word16)-11264)<0 ) {
            tmp16 = (Word16) -11264;
          }
          decstat->prev_parameters_tdbwe[i+G729EV_TDBWE_PAROFS_FREQ_ENVELOPE] = tmp16;
        }
      }


      G729EV_TDBWE_decoder(&decstat->tdbwe, &decstat->prev_nb_celp_param,
                           output_hiTdbwe, decstat->prev_parameters_tdbwe);

      /* 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
    {
      G729EV_G729_Set_zero(output_hiTdbwe, G729EV_MAIN_L_FRAME2);
    }

    /* TDAC decoder in FEC */
    IF(decstat->low_delay == 0)
    {
      /* set 3000-4000 Hz band of TDBWE synthesis to zero */
      norm_local = G729EV_TDAC_mdct(decstat->mem_mdct_hi, output_hiTdbwe, yq_hi, -15);
      G729EV_TDAC_mdct(decstat->mem_mdct_hi, output_hiTdbwe, yq_hi, norm_local);
      G729EV_G729_Set_zero(&yq_hi[G729EV_MAIN_L_FRAME2 - G729EV_G729_L_SUBFR], G729EV_G729_L_SUBFR);

      /* inverse MDCT to obtain reconstructed signal in higher band */
      G729EV_TDAC_inv_mdct(output_hi, yq_hi, decstat->mem_inv_mdct_hi, norm_local);
    }
    ELSE
    {
      G729EV_G729_Copy(output_hiTdbwe, output_hi, G729EV_MAIN_L_FRAME2);
    }

    /*************************
     * Postfilter lower band *
     *************************/

    /* set adaptive gamma paramaters of postfilter */
    G729EV_MAIN_set_gamma(output_lo, decstat->tab_Th, decstat->prev_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;
    ptr_Az = decstat->mem_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)
    {
      t0_first = decstat->mem_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);
    }

    /**************************
     * Postprocess lower band *
     **************************/

    /* G729 postprocessing */
    G729EV_G729_Copy(output_lo, pst_in, G729EV_MAIN_L_FRAME2);
    G729EV_MAIN_iir2(&decstat->mem_postpro, output_lo, G729EV_MAIN_L_FRAME2, G729EV_MAIN_b100, G729EV_MAIN_a100, 1);
    IF(decstat->mem_postflag == 0)
    {
      /* wideband bit rate -> leave lower-band unprocessed */
      FOR(i = 0; i < G729EV_MAIN_L_FRAME2; i++)
      {
        output_lo[i] = shl(pst_in[i], 1);
#if(WMOPS)
        move16();
#endif
      }
    }

    /******************************************************************
     * Fold higher band and combine bands by QMF synthesis filterbank *
     ******************************************************************/

    IF(decstat->f8 == 0)
    {                           /* test if 8kHz sampled output */
      /* mirror signal prior to filterbank synthesis */
      G729EV_MAIN_QMF_mirror(output_hi, G729EV_MAIN_L_FRAME2);

      /* synthesis filterbank */
      G729EV_MAIN_QMF_syn(&decstat->qmf_syn, output_lo, output_hi, tabout, G729EV_MAIN_L_FRAME2,
                          G729EV_MAIN_switching_gain[decstat->count_rcv]);
    }
    ELSE
    {
      G729EV_G729_Copy(output_lo, tabout, G729EV_MAIN_L_FRAME2);
    }

    /*******************
     * Update memories *
     *******************/

    /* Update to be done before decoding a good frame */
    decstat->decStG729.bfi_cnt = add(decstat->decStG729.bfi_cnt, 1);

    /* set buffer for W(z) */
    G729EV_G729_Set_zero(decstat->mem_invWz_in, G729EV_G729_M);
    G729EV_G729_Set_zero(decstat->mem_invwsp, G729EV_G729_M);
  }

  decstat->prev_bfi = bfi;
#if(WMOPS)
  move16();
#endif
}