decld8cp.c

语音编码G.729 语音编码G.729

            pA_t = A_t_fwd;
            m_aq = M;
            /* update the previous filter for the next frame */
            copy(&A_t_fwd[MP1], state->prev_filter, MP1);
            /*for(i=MP1; i<M_BWDP1; i++) state->prev_filter[i] = (F)0.;*/
            set_zero(state->prev_filter + MP1, M_BWDP1 - MP1);
        }
        else
		{
            int_bwd(A_t_bwd, state->prev_filter, &state->c_int);
            pA_t = A_t_bwd;
            m_aq = M_BWD;
            /* update the previous filter for the next frame */
            copy(&A_t_bwd[M_BWDP1], state->prev_filter, M_BWDP1);
        }

        /*------------------------------------------------------------------------*
        *          Loop for every subframe in the analysis frame                 *
        *------------------------------------------------------------------------*
        * The subframe size is L_SUBFR and the loop is repeated L_FRAME/L_SUBFR  *
        *  times                                                                 *
        *     - decode the pitch delay                                           *
        *     - decode algebraic code                                            *
        *     - decode pitch and codebook gains                                  *
        *     - find the excitation and compute synthesis speech                 *
        *------------------------------------------------------------------------*/

        for (i_subfr = 0; i_subfr < L_FRAME; i_subfr += L_SUBFR)
		{
            index = *parm++;            /* pitch index */

            if (i_subfr == 0)
			{
                if (rate == G729D)
                    i = 0;      /* no pitch parity at 6.4 kb/s */
                else
                    i = *parm++;             /* get parity check result */
                bad_pitch = bfi + i;     
                if( bad_pitch == 0) {
                    dec_lag3cp(index, PIT_MIN, PIT_MAX, i_subfr, &t0, &t0_frac, rate);
                    state->prev_t0 = t0;
                    state->prev_t0_frac = t0_frac;
                }
                else {                     /* Bad frame, or parity error */
                    if (bfi == 0) printf(" ! Wrong Pitch 1st subfr. !   ");
                    t0  =  state->prev_t0;
                    if (rate == G729E) {
                        t0_frac = state->prev_t0_frac;
                    }
                    else {
                        t0_frac = 0;
                        state->prev_t0++;
                        if(state->prev_t0 > PIT_MAX) {
                            state->prev_t0 = PIT_MAX;
                        }
                    }
                }
                *t0_first = t0;         /* If first frame */
            }
            else {                       /* second subframe */
                
                if( bfi == 0) {
                    dec_lag3cp(index, PIT_MIN, PIT_MAX, i_subfr, &t0, &t0_frac, rate);
                    state->prev_t0 = t0;
                    state->prev_t0_frac = t0_frac;
                }
                else {
                    t0  =  state->prev_t0;
                    if (rate == G729E) {
                        t0_frac = state->prev_t0_frac;
                    }
                    else {
                        t0_frac = 0;
                        state->prev_t0++;
                        if (state->prev_t0 > PIT_MAX) state->prev_t0 = PIT_MAX;
                    }
                }
            }
            /*-------------------------------------------------*
            * - Find the adaptive codebook vector.            *
            *-------------------------------------------------*/
            pred_lt_3(&state->exc[i_subfr], t0, t0_frac, L_SUBFR);
            
            /* --------------------------------- */
            /* pitch tracking for frame erasures */
            /* --------------------------------- */
            if( rate == G729E) {
                track_pit(&state->prev_t0, &state->prev_t0_frac, &state->prev_pitch, &state->stat_pitch,
                    &state->pitch_sta, &state->frac_sta);
            }
            else {
                i = state->prev_t0;
                j = state->prev_t0_frac;
                track_pit(&i, &j, &state->prev_pitch, &state->stat_pitch,
                    &state->pitch_sta, &state->frac_sta);
            }

            /*-------------------------------------------------------*
            * - Decode innovative codebook.                         *
            *-------------------------------------------------------*/
            if (bfi != 0) {        /* Bad frame */
                
                parm[0] = (int)random_g729c(&state->seed_fer);
                parm[1] = (int)random_g729c(&state->seed_fer);
                if (rate == G729E) {
                    parm[2] = (int)random_g729c(&state->seed_fer);
                    parm[3] = (int)random_g729c(&state->seed_fer);
                    parm[4] = (int)random_g729c(&state->seed_fer);
                }
                
            }
            
            stationnary = 0; /* to avoid visual warning */
            if (rate == G729) {
                /* case 8 kbps */
                decod_ACELP(parm[1], parm[0], code);
                parm += 2;
                /* for gain decoding in case of frame erasure */
                state->stat_bwd = 0;
                stationnary = 0;
            }
            else if (rate == G729D) {
                /* case 8 kbps */
                decod_ACELP64(parm[1], parm[0], code);
                parm += 2;
                /* for gain decoding in case of frame erasure */
                state->stat_bwd = 0;
                stationnary = 0;
            }
            else if (rate == G729E)
			{
                /* case 11.8 kbps */
                if (lp_mode == 0) {
                    dec_ACELP_10i40_35bits(parm, code);
                    /* for gain decoding in case of frame erasure */
                    state->stat_bwd = 0;
                    stationnary = 0;
                }
                else
				{
                    dec_ACELP_12i40_44bits(parm, code);
                    /* for gain decoding in case of frame erasure */
                    state->stat_bwd++;
                    if (state->stat_bwd >= 30) {
                        stationnary = 1;
                        state->stat_bwd = 30;
                    }
                    else stationnary = 0;
                }
                parm += 5;
            }
            
            /*-------------------------------------------------------*
            * - Add the fixed-gain pitch contribution to code[].    *
            *-------------------------------------------------------*/
            for (i = t0; i < L_SUBFR; i++)   code[i] += state->sharp * code[i-t0];

            /*-------------------------------------------------*
            * - Decode pitch and codebook gains.              *
            *-------------------------------------------------*/
            index = *parm++;      /* index of energy VQ */

            if (rate == G729D)
                dec_gain_6k(&state->gain_s, index, code, L_SUBFR, bfi, &state->gain_pitch, &state->gain_code);
            else
                dec_gaine(&state->gain_s, index, code, L_SUBFR, bfi, &state->gain_pitch, &state->gain_code, rate,
                    state->gain_pit_mem, state->gain_cod_mem, &state->c_muting, state->count_bfi, stationnary);
            
                /*-------------------------------------------------------------*
                * - Update previous gains
            *-------------------------------------------------------------*/
            state->gain_pit_mem = state->gain_pitch;
            state->gain_cod_mem = state->gain_code;
            /*-------------------------------------------------------------*
            * - Update pitch sharpening "sharp" with quantized gain_pitch *
            *-------------------------------------------------------------*/
            state->sharp = state->gain_pitch;
            if (state->sharp > SHARPMAX) state->sharp = SHARPMAX;
            if (state->sharp < SHARPMIN) state->sharp = SHARPMIN;
            
            /*-------------------------------------------------------*
            * - Find the total excitation.                          *
            * - Find synthesis speech corresponding to exc[].       *
            *-------------------------------------------------------*/
            if (bfi != 0)
			{	/* Bad frame */
                state->count_bfi++;
                if (voicing == 0 ) {
                    g_p = (F)0.;
                    g_c = state->gain_code;
                }
                else {
                    g_p = state->gain_pitch;
                    g_c = (F)0.;
                }
            }
            else
			{
                g_p = state->gain_pitch;
                g_c = state->gain_code;
            }
        
            for (i = 0; i < L_SUBFR;  i++) {
                state->exc[i+i_subfr] = g_p * state->exc[i+i_subfr] + g_c * code[i];
            }
            
            if (rate == G729D) {
                PhDisp(&state->cng_s.phdisp_s, &state->exc[i_subfr], exc_phdisp, state->gain_code, state->gain_pitch, code);
                syn_filte(m_aq, pA_t, exc_phdisp, &synth[i_subfr], L_SUBFR,
                                &state->mem_syn[M_BWD-m_aq], 0);
            }
            else {
                syn_filte(m_aq, pA_t, &state->exc[i_subfr], &synth[i_subfr], L_SUBFR,
                                    &state->mem_syn[M_BWD-m_aq], 0);

                /* Updates state machine for phase dispersion in
                6.4 kbps mode, if running at other rate */
                Update_PhDisp(&state->cng_s.phdisp_s, state->gain_pitch, state->gain_code);
            }

            copy(&synth[i_subfr+L_SUBFR-M_BWD], state->mem_syn, M_BWD);

            pA_t += m_aq+1;    /* interpolated LPC parameters for next subframe */

        }
    }

    /*------------*
     *  For G729b
     *-----------*/
    if (bfi == 0)
	{
        state->sid_sav = (FLOAT)0.0;
        for(i=0; i<L_FRAME; i++) {
            state->sid_sav += state->exc[i] * state->exc[i];
        }
    }
    state->past_ftyp = ftyp;

    /*------------*
     *  For G729E
     *-----------*/
    energy = ener_dB(synth, L_FRAME);
    if (energy >= (F)40.) tst_bwd_dominant(&state->bwd_s, bwd_dominant, lp_mode);

    /*--------------------------------------------------*
    * Update signal for next frame.                    *
    * -> shift to the left by L_FRAME  exc[]           *
    *--------------------------------------------------*/
    copy(&state->old_exc[L_FRAME], &state->old_exc[0], PIT_MAX+L_INTERPOL);

    if (lp_mode == 0) {
        copy(A_t_fwd, Az_dec, 2*MP1);
        *m_pst = M;
    }
    else {
        copy(A_t_bwd, Az_dec, 2*M_BWDP1);
        *m_pst = M_BWD;
    }
    
    state->prev_bfi     = bfi;
    state->prev_lp_mode = lp_mode;
    state->prev_voicing = voicing;
    
    if (bfi != 0)
		state->c_fe = (F)1.;
    else {
        if (lp_mode == 0)
			state->c_fe = 0;
        else {
            if (*bwd_dominant == 1)
				state->c_fe -= (F)0.1;
            else
				state->c_fe -= (F)0.5;
            if (state->c_fe < 0)  state->c_fe = 0;
        }
    }
}