phi_axit.c

MPEG2/MPEG4编解码参考程序(实现了MPEG4的部分功能)

    float *h;           /* Array for the impulse response  of 1/A(z)    */
    float *t;           /* Array for the cbk-search target signal       */
    float *e;
    float *vtmp;        /* Temporary Array (Used duing Backward Filt    */
    float *scratch;     /* Temporary Array (Used duing Backward Filt    */
    long  **fixed_cbk;  /* 2-d Array for generating the fixed codebook  */
    float cba_gain;     /* Adaptive Codebook Gain                       */
    float cbf_gain;     /* Fixed Codebook  Gain                         */
    long  cbf_pi[FCBK_PRESELECT_VECS];   /* Array for pre-selected fixed cbk candidates  */
    long  phase;        /* Phase of the RPE codebook                    */
    int   i;            /* Local indices                                */
    
    /*==================================================================*/
    /* Memory allocation for temporary arrays                           */
    /*==================================================================*/
    if
    (  
    (( h = (float *)malloc((unsigned int)sbfrm_size * sizeof(float)))    == NULL ) ||
    (( t = (float *)malloc((unsigned int)sbfrm_size * sizeof(float)))    == NULL ) || 
    (( e = (float *)malloc((unsigned int)sbfrm_size * sizeof(float)))    == NULL ) ||
    (( amp  = (long *)malloc((unsigned int)PHI_Np * sizeof(long)))       == NULL ) ||
    (( pos  = (long *)malloc((unsigned int)PHI_Np * sizeof(long)))       == NULL ) ||
    (( scratch = (float *)malloc((unsigned int)sbfrm_size * sizeof(float)))== NULL ) ||
    (( vtmp = (float *)malloc((unsigned int)sbfrm_size * sizeof(float))) == NULL ) 
    ) 
    {
       printf("ERROR: Malloc Failure in Block: Excitation Anlaysis \n");
       exit(1);
    }

    if ((fixed_cbk = (long **) malloc((unsigned int)PHI_Nf * sizeof(long *))) == NULL)
    { 
        printf("Malloc failure in Block:Excitation Anlysis\n");
        exit(1);
    }    
    for (i = 0; i < (int)PHI_Nf; i++)
    {
        fixed_cbk[i] = (long *) malloc ((unsigned int)sbfrm_size * sizeof (long));
        if (fixed_cbk[i] == NULL)
        {
            printf("ERROR: Malloc Failure in Block: Excitation Anlaysis \n");
            exit (1);
        }
    }
    
    /*==================================================================*/
    /* Make sure the number of shape and gain codebooks is correct      */
    /*==================================================================*/
    if (num_shape_cbks != 2)
    { 
        fprintf(stderr, "Wrong number of shape codebooks in Block: Excitation Anlysis\n");
        exit(1);
    }    
    if (num_gain_cbks != 2)
    { 
        fprintf(stderr, "Wrong number of gain codebooks in Block: Excitation Anlysis\n");
        exit(1);
    }    

    /*==================================================================*/
    /* We need to know which subframe we are in                         */
    /*==================================================================*/
    if (PHI_sbfrm_ctr % n_subframes == 0)
    {
        PHI_sbfrm_ctr = 0;
    }

    /*==================================================================*/
    /*  2.7 perceptual weighting filter                                 */
    /*==================================================================*/
    PHI_perceptual_weighting(sbfrm_size, lpc_residual, scratch, lpc_order, int_Qlpc_coefficients, PHI_Wden_states);
    
    
    /*==================================================================*/
    /*   2.9 zero-input response, weighted target signal and impulse    */
    /*       response calculator                                        */
    /*==================================================================*/
    PHI_calc_impulse_response(sbfrm_size, h, lpc_order, int_Qlpc_coefficients);
    PHI_calc_zero_input_response(sbfrm_size, vtmp, lpc_order, int_Qlpc_coefficients, PHI_s_state);
    PHI_calc_weighted_target(sbfrm_size, scratch, vtmp, t);
    
    
    if (PHI_sbfrm_ctr == n_subframes/2)
    {
       PHI_afp  = first_order_lpc_par;
    }
    PHI_afp  = first_order_lpc_par;

    /*==============================================================*/
    /*  2.10 adaptive codebook search - preselection                */
    /*==============================================================*/

    PHI_backward_filtering(sbfrm_size, t, vtmp, h);

    PHI_cba_preselection(sbfrm_size, Lmax, Lmin, n_subframes,
    n_lag_candidates, PHI_cba_codebook, vtmp, PHI_afp, lag_candidates, PHI_sbfrm_ctr);
    
    /*==================================================================*/
    /* 2.11 adaptive codebook search                                    */
    /*==================================================================*/
    PHI_cba_search(sbfrm_size, (long)Lmax, (long)Lmin, PHI_cba_codebook, lag_candidates, n_lag_candidates, h, t, &cba_gain,
    &shape_indices[0], &gain_indices[0]);
              
    PHI_calc_cba_excitation(sbfrm_size, Lmax, Lmin, PHI_cba_codebook, *shape_indices, scratch);
    
    PHI_calc_cba_residual(sbfrm_size, scratch, cba_gain, h, t, e);
    
    /*==================================================================*/
    /*          2.12 fixed codebook search - preselection               */
    /*      REDUCED COMPLEXITY FIXED CODEBOOK PRESELECTION              */ 
    /*==================================================================*/
    
    PHI_backward_filtering(sbfrm_size, e, vtmp, h);
    
    PHI_calc_cbf_phase(PHI_D,  sbfrm_size, vtmp, &phase);
    
    PHI_CompAmpArray(PHI_Np, PHI_D, vtmp, phase, amp);
    
    PHI_CompPosArray(PHI_Np, PHI_D, PHI_Nz, vtmp, phase, pos);
   
    PHI_generate_cbf(PHI_Np, PHI_D, PHI_Nf, sbfrm_size, fixed_cbk, phase, amp, pos);
    
    PHI_cbf_preselection((long)PHI_D, (long)FCBK_PRESELECT_VECS, PHI_Nf, sbfrm_size, fixed_cbk, phase, vtmp,
    PHI_afp, cbf_pi);

    /*==================================================================*/
    /* 2.13 fixed codebook search                                       */
    /*==================================================================*/

    PHI_cbf_search(PHI_Np, (long)PHI_D, (long)FCBK_PRESELECT_VECS, sbfrm_size, fixed_cbk, phase, cbf_pi, h, e, &cbf_gain,
    &gain_indices[1], amp, PHI_sbfrm_ctr);

    /*==================================================================*/
    /* 2.13 Code RPE index and phase into fixed_cbk_index               */
    /*==================================================================*/
    PHI_code_cbf_amplitude_phase(PHI_Np, (long)PHI_D, amp, phase, &shape_indices[1]);

    /*==================================================================*/
    /*   2.14 simulation of decoder                                     */
    /*==================================================================*/

    PHI_calc_cbf_excitation(sbfrm_size, PHI_Np, (long)PHI_D, amp, phase, vtmp);
    
    PHI_sum_excitations(sbfrm_size, cba_gain, scratch, cbf_gain, vtmp, decoded_excitation);
    
    PHI_update_cba_memory(sbfrm_size, Lmax, PHI_cba_codebook, decoded_excitation);
    
    PHI_update_filter_states(sbfrm_size, lpc_order, decoded_excitation, PHI_s_state, int_Qlpc_coefficients);
    
    /*==================================================================*/
    /*   Update the subframe counter                                    */
    /*==================================================================*/
    
    PHI_sbfrm_ctr++;

    /*==================================================================*/
    /* Free temp states                                                 */
    /*==================================================================*/
    free(h);
    free(t);
    free(e);
    free(amp);
    free(pos);
    free(vtmp);
    free(scratch);
    for (i = 0; i < (int)PHI_Nf; i++)
    {
        free(fixed_cbk[i]);
    }
    free(fixed_cbk);

}

/*======================================================================*/
/* Function Definition: PHI_close_excitation_analysis                   */
/*======================================================================*/
void PHI_close_excitation_analysis(void)
{
    free (PHI_Wden_states);
    free (PHI_s_state);
    free (PHI_cba_codebook);
}
   
/*======================================================================*/
/*      H I S T O R Y                                                   */
/*======================================================================*/
/* 17-04-96 R. Taori  Initial Version                                   */
/* 30-06-96 R. Taori  Modified interface  to meet the MPEG-4 requirement*/
/* 20-08-96 R. Taori  Modified interface to accomodate Tampere results  */