imdct.c

MPEG2/MPEG4编解码参考程序(实现了MPEG4的部分功能)

      vmult( transf_buf+nlong, window_long+nlong-1, transf_buf+nlong, 1, -1, 1, nlong );
    }

    break; 
 
  case LONG_START_SEQUENCE : 
    imdct( p_in_data, transf_buf, 2*nlong ); 
    vmult( transf_buf, window_long_prev, transf_buf, 1, 1, 1, nlong ); 
    if (overlap_select != NON_OVERLAPPED_MODE) {
      vadd( transf_buf, o_buf, o_buf, 1, 1, 1, nlong ); 
      vcopy( transf_buf+nlong, o_buf+nlong, 1, 1, nflat_ls ); 
      vmult( transf_buf+nlong+nflat_ls, window_short+nshort-1, o_buf+nlong+nflat_ls, 1, -1, 1, nshort ); 
      vcopy( &zero, o_buf+2*nlong-1, 0, -1, nflat_ls ); 
    }
    else { /* overlap_select == NON_OVERLAPPED_MODE */
      vmult( transf_buf+nlong+nflat_ls, window_short+nshort-1, transf_buf+nlong+nflat_ls, 1, -1, 1, nshort ); 
      vcopy( &zero, transf_buf+2*nlong-1, 0, -1, nflat_ls ); 
    }
    break; 
    
  case LONG_STOP_SEQUENCE : 
    imdct( p_in_data, transf_buf, 2*nlong ); 
    vmult( transf_buf+nflat_ls, window_short_prev_ptr, transf_buf+nflat_ls, 1, 1, 1, nshort ); 
    if (overlap_select != NON_OVERLAPPED_MODE) {
      vadd( transf_buf+nflat_ls, o_buf+nflat_ls, o_buf+nflat_ls, 1, 1, 1, nshort ); 
      vcopy( transf_buf+nflat_ls+nshort, o_buf+nflat_ls+nshort, 1, 1, nflat_ls ); 
      vmult( transf_buf+nlong, window_long+nlong-1, o_buf+nlong, 1, -1, 1, nlong ); 
    }
    else { /* overlap_select == NON_OVERLAPPED_MODE */
      vcopy( &zero, transf_buf, 0, 1, nflat_ls);
      vmult( transf_buf+nlong, window_long+nlong-1, transf_buf+nlong, 1, -1, 1, nlong);
    }
    break; 
 
  case EIGHT_SHORT_SEQUENCE : 
    {int ii; for(ii=0; ii<2*nlong; ii++) transf_buf[ii]=0;}
    if (overlap_select != NON_OVERLAPPED_MODE) {
      fp = o_buf + nflat_ls; 
    }
    else { /* overlap_select == NON_OVERLAPPED_MODE */
      fp = transf_buf;
    }
    for( k = num_short_win-1; k-->= 0; ) { 
      if (overlap_select != NON_OVERLAPPED_MODE) {
        imdct( p_in_data, transf_buf, 2*nshort ); 
        vmult( transf_buf, window_short_prev_ptr, transf_buf, 1, 1, 1, nshort ); 
        vadd( transf_buf, fp, fp, 1, 1, 1, nshort ); 
        vmult( transf_buf+nshort, window_short+nshort-1, fp+nshort, 1, -1, 1, nshort ); 
        p_in_data += nshort; 
        fp        += nshort; 
        window_short_prev_ptr = window_short; 
      }
      else { /* overlap_select == NON_OVERLAPPED_MODE */
        imdct( p_in_data, fp, 2*nshort );
        vmult( fp, window_short_prev_ptr, fp, 1, 1, 1, nshort ); 
        vmult( fp+nshort, window_short+nshort-1, fp+nshort, 1, -1, 1, nshort ); 
        p_in_data += nshort; 
        fp        += 2*nshort;
        window_short_prev_ptr = window_short; 
      }
    } 
    vcopy( &zero, o_buf+2*nlong-1, 0, -1, nflat_ls ); 
    break;     
    
#if 0 /* not used anymore */
  case LONG_MEDIUM_WINDOW : 
    imdct( p_in_data, transf_buf, 2*nlong ); 
    vmult( transf_buf, window_long_prev, transf_buf, 1, 1, 1, nlong ); 
    vadd( transf_buf, o_buf, o_buf, 1, 1, 1, nlong ); 
    vcopy( transf_buf+nlong, o_buf+nlong, 1, 1, nflat_lm ); 
    vmult( transf_buf+nlong+nflat_lm, window_med+nmed-1, o_buf+nlong+nflat_lm, 1, -1, 1, nmed ); 
    vcopy( &zero, o_buf+2*nlong-1, 0, -1, nflat_lm ); 
    break; 
 
   case MEDIUM_LONG_WINDOW : 
    imdct( p_in_data, transf_buf, 2*nlong ); 
    vmult( transf_buf+nflat_lm, window_med, transf_buf+nflat_lm, 1, 1, 1, nmed ); 
    vadd( transf_buf+nflat_lm, o_buf+nflat_lm, o_buf+nflat_lm, 1, 1, 1, nmed ); 
    vcopy( transf_buf+nflat_lm+nmed, o_buf+nflat_lm+nmed, 1, 1, nflat_lm ); 
    vmult( transf_buf+nlong, window_long+nlong-1, o_buf+nlong, 1, -1, 1, nlong ); 
    break; 
 
   case ONLY_MEDIUM_WINDOW : 
    fp = o_buf + nflat_lm; 
    for( k = transfak_lm-1; k-->=0; ) { 
      imdct( p_in_data, transf_buf, 2*nmed ); 
      vmult( transf_buf, window_med, transf_buf, 1, 1, 1, nmed ); 
      vadd( transf_buf, fp, fp, 1, 1, 1, nmed ); 
      vmult( transf_buf+nmed, window_med+nmed-1, fp+nmed, 1, -1, 1, nmed ); 
      p_in_data += nmed; 
      fp        += nmed; 
    } 
    vcopy( &zero, o_buf+2*nlong-1, 0, -1, nflat_lm ); 
    break; 
 
   case MEDIUM_SHORT_WINDOW : 
    fp = o_buf + nflat_lm; 
    for( k = transfak_lm-2; k-->=0; ) {  /* NI */
      imdct( p_in_data, transf_buf, 2*nmed ); 
      vmult( transf_buf, window_med, transf_buf, 1, 1, 1, nmed ); 
      vadd( transf_buf, fp, fp, 1, 1, 1, nmed ); 
      vmult( transf_buf+nmed, window_med+nmed-1, fp+nmed, 1, -1, 1, nmed ); 
      p_in_data += nmed; 
      fp        += nmed; 
    } 
    imdct( p_in_data, transf_buf, 2*nmed ); 
    vmult( transf_buf, window_med, transf_buf, 1, 1, 1, nmed ); 
    vadd( transf_buf, fp, fp, 1, 1, 1, nmed ); 
    vcopy( transf_buf+nmed, fp+nmed, 1, 1, nflat_ms ); 
    vmult( transf_buf+nmed+nflat_ms, window_short+nshort-1, fp+nmed+nflat_ms, 1, -1, 1, nshort ); 
    break; 
 
   case SHORT_MEDIUM_WINDOW : 
    fp = o_buf + nflat_lm; 
    imdct( p_in_data, transf_buf, 2*nmed ); 
    vmult( transf_buf+nflat_ms, window_short_prev_ptr, transf_buf+nflat_ms, 1, 1, 1, nshort ); 
    vadd( transf_buf+nflat_ms, fp+nflat_ms, fp+nflat_ms, 1, 1, 1, nshort ); 
    vcopy( transf_buf+nflat_ms+nshort, fp+nflat_ms+nshort, 1, 1, nflat_ms ); 
    vmult( transf_buf+nmed, window_med+nmed-1, fp+nmed, 1, -1, 1, nmed ); 
    fp        += nmed; 
    p_in_data += nmed; 
    for( k = transfak_lm-2; k-->=0; ) { /* NI */
      imdct( p_in_data, transf_buf, 2*nmed ); 
      vmult( transf_buf, window_med, transf_buf, 1, 1, 1, nmed ); 
      vadd( transf_buf, fp, fp, 1, 1, 1, nmed ); 
      vmult( transf_buf+nmed, window_med+nmed-1, fp+nmed, 1, -1, 1, nmed ); 
      p_in_data += nmed; 
      fp        += nmed; 
    } 
    break; 
#endif
 
   default : 
    CommonExit( 1, "mdct_synthesis: Unknown window type(1)" ); 
  } 
 
  if (overlap_select != NON_OVERLAPPED_MODE) {
    vcopy( o_buf, p_out_data, 1, 1, nlong ); 
  }
  else { /* overlap_select == NON_OVERLAPPED_MODE */
    vcopy( transf_buf, p_out_data, 1, 1, 2*nlong ); 
  }
  
  /* save unused output data */ 
  if (overlap_select != NON_OVERLAPPED_MODE)
  vcopy( o_buf+nlong, p_overlap, 1, 1, nlong ); 
} 



/* %%%%%%%%%%%%%%%%% MDCT - STUFF %%%%%%%%%%%%%%%% */

void mdct( double in_data[], double out_data[], int len )
{
  double *tmp_data;

  tmp_data = (double*)malloc(len*sizeof(double));
  vcopy(in_data, tmp_data, 1, 1, len); 
  MDCT(tmp_data, len, len/2, 1);
  vcopy(tmp_data, out_data, 1, 1, len/2); 
  free(tmp_data);
}


void buffer2freq(
  double           p_in_data[], 
  double           p_out_mdct[],
  double           p_overlap[],
  WINDOW_SEQUENCE  windowSequence,
  WINDOW_SHAPE     wfun_select,      /* offers the possibility to select different window functions */
  WINDOW_SHAPE     wfun_select_prev,
  int              nlong,            /* shift length for long windows   */
  int              nmed,             /* shift length for medium windows */
  int              nshort,           /* shift length for short windows  */
  Mdct_in          overlap_select,   /* select mdct input *TK*          */
                                     /* switch (overlap_select) {       */
                                     /* case OVERLAPPED_MODE:                */
                                     /*   p_in_data[]                   */
                                     /*   = overlapped signal           */
                                     /*         (bufferlength: nlong)   */
                                     /* case NON_OVERLAPPED_MODE:            */
                                     /*   p_in_data[]                   */
                                     /*   = non overlapped signal       */
                                     /*         (bufferlength: 2*nlong) */
  int              num_short_win     /* number of short windows to      */
                                     /* transform                       */
  /*int              save_window*/       /* save window information         */
)
{
  double         transf_buf[ 2*MAX_SHIFT_LEN_LONG ];
  double         windowed_buf[ 2*MAX_SHIFT_LEN_LONG ];
  double           *p_o_buf;
  int             k;

  double           window_long[MAX_SHIFT_LEN_LONG]; 
  double           window_long_prev[MAX_SHIFT_LEN_LONG]; 
  double           window_med[MAX_SHIFT_LEN_LONG]; 
  double           window_med_prev[MAX_SHIFT_LEN_LONG]; 
  double           window_short[MAX_SHIFT_LEN_LONG]; 
  double           window_short_prev[MAX_SHIFT_LEN_LONG]; 
  double           *window_short_prev_ptr;


  int nflat_ls    = (nlong-nshort)/ 2; 
  int transfak_ls =  nlong/nshort; 
  int transfak_lm =  nlong/nmed; 
#if 0 /* not used anymore */
  int nflat_lm    = (nlong-nmed)  / 2; 
  int nflat_ms    = (nmed-nshort) / 2; 
#endif
  static int firstTime=1;
  window_short_prev_ptr = window_short_prev ; 


  if( (nlong%nshort) || (nlong > MAX_SHIFT_LEN_LONG) || (nshort > MAX_SHIFT_LEN_LONG/2) ) { 
    CommonExit( 1, "mdct_analysis: Problem with window length" ); } 
  if( (nlong%nmed) || (nmed%nshort) || (nmed > MAX_SHIFT_LEN_LONG/2) ) { 
    CommonExit( 1, "mdct_analysis: Problem with window length" );  } 
  if( transfak_lm%2 ) { 
    CommonExit( 1, "mdct_analysis: Problem with window length" );  } 
  if( windowSequence==EIGHT_SHORT_SEQUENCE
      && ( (num_short_win <= 0) || (num_short_win > transfak_ls) ) ) {
    CommonExit( 1, "mdct_analysis: Problem with number of short windows" );  } 
  
  calc_window( window_long,      nlong, wfun_select ); 
  calc_window( window_long_prev, nlong, wfun_select_prev ); 
  calc_window( window_med, nmed, wfun_select ); 
  calc_window( window_med_prev, nmed, wfun_select_prev ); 
  calc_window( window_short,      nshort, wfun_select ); 
  calc_window( window_short_prev, nshort, wfun_select_prev ); 
  
  if (overlap_select != NON_OVERLAPPED_MODE) {
    /* create / shift old values */
    /* We use p_overlap here as buffer holding the last frame time signal*/
    if (firstTime){
      firstTime=0;
      vcopy( &zero, transf_buf, 0, 1, nlong );
    }
    else
      vcopy( p_overlap, transf_buf, 1, 1, nlong );

    /* Append new data */
    vcopy( p_in_data, transf_buf+nlong, 1, 1, nlong );
    vcopy( p_in_data, p_overlap,        1, 1, nlong );
  }
  else { /* overlap_select == NON_OVERLAPPED_MODE */
    vcopy( p_in_data, transf_buf, 1, 1, 2*nlong);
  }

  /* Set ptr to transf-Buffer */
  p_o_buf = transf_buf;
  
  
  /* Separate action for each Block Type */
  switch( windowSequence ) {
   case ONLY_LONG_SEQUENCE :
     vmult( p_o_buf, window_long_prev, windowed_buf,       1, 1,  1, nlong );
     vmult( p_o_buf+nlong, window_long+nlong-1, windowed_buf+nlong, 1, -1, 1, nlong );
     mdct( windowed_buf, p_out_mdct, 2*nlong );    
     break;
   
   case LONG_START_SEQUENCE :
    vmult( p_o_buf, window_long_prev, windowed_buf, 1, 1, 1, nlong );
    vcopy( p_o_buf+nlong, windowed_buf+nlong, 1, 1, nflat_ls );
    vmult( p_o_buf+nlong+nflat_ls, window_short+nshort-1, windowed_buf+nlong+nflat_ls, 1, -1, 1, nshort );
    vcopy( &zero, windowed_buf+2*nlong-1, 0, -1, nflat_ls );
    mdct( windowed_buf, p_out_mdct, 2*nlong );
    break;

   case LONG_STOP_SEQUENCE :
    vcopy( &zero, windowed_buf, 0, 1, nflat_ls );
    vmult( p_o_buf+nflat_ls, window_short_prev_ptr, windowed_buf+nflat_ls, 1, 1, 1, nshort );
    vcopy( p_o_buf+nflat_ls+nshort, windowed_buf+nflat_ls+nshort, 1, 1, nflat_ls );
    vmult( p_o_buf+nlong, window_long+nlong-1, windowed_buf+nlong, 1, -1, 1, nlong );
    mdct( windowed_buf, p_out_mdct, 2*nlong );
    break;

   case EIGHT_SHORT_SEQUENCE :
    if (overlap_select != NON_OVERLAPPED_MODE) {
      p_o_buf += nflat_ls;
    }
    for (k=num_short_win-1; k-->=0; ) {
      vmult( p_o_buf,        window_short_prev_ptr,          windowed_buf,        1, 1,  1, nshort );
      vmult( p_o_buf+nshort, window_short+nshort-1, windowed_buf+nshort, 1, -1, 1, nshort );
      mdct( windowed_buf, p_out_mdct, 2*nshort );

      p_out_mdct += nshort;
      p_o_buf    += (overlap_select != NON_OVERLAPPED_MODE) ? nshort : 2*nshort;
      window_short_prev_ptr = window_short; 
    }
    break;
#if 0 /* not used anymore */
   case LONG_MEDIUM_WINDOW :
    vmult( p_o_buf, window_long_prev, windowed_buf, 1, 1, 1, nlong );
    vcopy( p_o_buf+nlong, windowed_buf+nlong, 1, 1, nflat_lm );
    vmult( p_o_buf+nlong+nflat_lm, window_med+nmed-1, windowed_buf+nlong+nflat_lm, 1, -1, 1, nmed );
    vcopy( &zero, windowed_buf+2*nlong-1, 0, -1, nflat_lm );
    mdct( windowed_buf, p_out_mdct, 2*nlong );
    break;

   case MEDIUM_LONG_WINDOW :
    vcopy( &zero, windowed_buf, 0, 1, nflat_lm );
    vmult( p_o_buf+nflat_lm, window_med, windowed_buf+nflat_lm, 1, 1, 1, nmed );
    vcopy( p_o_buf+nflat_lm+nmed, windowed_buf+nflat_lm+nmed, 1, 1, nflat_lm );
    vmult( p_o_buf+nlong, window_long+nlong-1, windowed_buf+nlong, 1, -1, 1, nlong );
    mdct( windowed_buf, p_out_mdct, 2*nlong );
    break;

   case ONLY_MEDIUM_WINDOW :
    p_o_buf += nflat_lm;
    for( k=transfak_lm-1; k-->=0; ) {
      vmult( p_o_buf,      window_med,        windowed_buf,      1, 1,  1, nmed );
      vmult( p_o_buf+nmed, window_med+nmed-1, windowed_buf+nmed, 1, -1, 1, nmed );
      mdct( windowed_buf, p_out_mdct, 2*nmed );

      p_o_buf    += nmed;
      p_out_mdct += nmed;
    }
    break;

   case MEDIUM_SHORT_WINDOW :
    p_o_buf += nflat_lm;
    for( k=transfak_lm-2; k-->=0; ) { /* NI */
      vmult( p_o_buf,      window_med,        windowed_buf,      1, 1,  1, nmed );
      vmult( p_o_buf+nmed, window_med+nmed-1, windowed_buf+nmed, 1, -1, 1, nmed );
      mdct( windowed_buf, p_out_mdct, 2*nmed );

      p_o_buf    += nmed;
      p_out_mdct += nmed;
    }
    vmult( p_o_buf, window_med, windowed_buf, 1, 1, 1, nmed );
    vcopy( p_o_buf+nmed, windowed_buf+nmed, 1, 1, nflat_ms );
    vmult( p_o_buf+nmed+nflat_ms, window_short+nshort-1, windowed_buf+nmed+nflat_ms, 1, -1, 1, nshort );
    vcopy( &zero, windowed_buf+2*nmed-1, 0, -1, nflat_ms );
    mdct( windowed_buf, p_out_mdct, 2*nmed );
    break;

   case SHORT_MEDIUM_WINDOW :
    p_o_buf += nflat_lm;
    vcopy( &zero, windowed_buf, 0, 1, nflat_ms );
    vmult( p_o_buf+nflat_ms, window_short_prev_ptr, windowed_buf+nflat_ms, 1, 1, 1, nshort );
    vcopy( p_o_buf+nflat_ms+nshort, windowed_buf+nflat_ms+nshort, 1, 1, nflat_ms );
    vmult( p_o_buf+nmed, window_med+nmed-1, windowed_buf+nmed, 1, -1, 1, nmed );
    mdct( windowed_buf, p_out_mdct, 2*nmed );

    p_o_buf    += nmed;
    p_out_mdct += nmed;
    for (k=transfak_lm-2; k-->=0; ) { /* NI */
      vmult( p_o_buf,      window_med,        windowed_buf,      1, 1,  1, nmed );
      vmult( p_o_buf+nmed, window_med+nmed-1, windowed_buf+nmed, 1, -1, 1, nmed );
      mdct( windowed_buf, p_out_mdct, 2*nmed );

      p_o_buf    += nmed;
      p_out_mdct += nmed;
    }
    break;
#endif
   default :
      CommonExit( 1, "mdct_synthesis: Unknown window type (2)" ); 
  }

  /* Set output data 
  vcopy(transf_buf, p_out_mdct,1, 1, nlong); */
 
}

/***********************************************************************************************/