funcg722.c

ITU-T G.191中包含的G.722语音压缩编解码程序

 ___________________________________________________________________________
*/
Word16 
scalel (nbpl)
Word16 nbpl;
{
  Word16          wd1, wd2;

  wd1 = (nbpl >> 6) & 511;
  wd2 = wd1 + 64;
  return ((ila[wd2] + 1) << 2);
}
/* ..................... End of scalel() ..................... */


/*___________________________________________________________________________
                                                                            
    Function Name : scaleh                                                  
                                                                            
    Purpose :                                                               
                                                                            
     .                  
                                                                            
    Inputs :                                                                
                                                                            
                                                                            
    Outputs :                                                               
                                                                            
     none                                                                   
                                                                            
    Return Value :                                                          
                                                                            
 ___________________________________________________________________________
*/
Word16 
scaleh (nbph)
Word16 nbph;
{
  Word16          wd;

  wd = (nbph >> 6) & 511;

  return ((ila[wd] + 1) << 2);
}
/* ..................... End of scaleh() ..................... */


/*___________________________________________________________________________
                                                                            
    Function Name : uppol1                                                  
                                                                            
    Purpose :                                                               
                                                                            
     .                  
                                                                            
    Inputs :                                                                
                                                                            
                                                                            
    Outputs :                                                               
                                                                            
     none                                                                   
                                                                            
    Return Value :                                                          
     None.                                                                  
 ___________________________________________________________________________
*/
void 
uppol1 (al, plt)
Word16 al [];
Word16 plt [];
{
  Word16          sg0, sg1, wd1, wd2, wd3, apl1;

  sg0 = shr (plt[0], 15);
  sg1 = shr (plt[1], 15);
  wd1 = (sg0 == sg1) ? 192 : -192;
  wd2 = mult (al[1], 32640);
  apl1 = add (wd1, wd2);
  wd3 = sub (15360, al[2]);
  apl1 = (apl1 > wd3) ? wd3 : ((apl1 < -wd3) ? negate (wd3) : apl1);

  /* Shift of the plt signals */
  plt[2] = plt[1];
  plt[1] = plt[0];

  al[1] = apl1;
}
/* ..................... End of uppol1() ..................... */


/*___________________________________________________________________________
                                                                            
    Function Name : uppol2                                                  
                                                                            
    Purpose :                                                               
                                                                            
     .                  
                                                                            
    Inputs :                                                                
                                                                            
                                                                            
    Outputs :                                                               
                                                                            
     none                                                                   
                                                                            
    Return Value :                                                          
     None.                                                                  
 ___________________________________________________________________________
*/
void 
uppol2 (al, plt)
Word16 al [];
Word16 plt [];
{
  Word16          sg0, sg1, sg2, wd1, wd2, wd3, wd4, wd5, apl2;

  sg0 = shr (plt[0], 15);
  sg1 = shr (plt[1], 15);
  sg2 = shr (plt[2], 15);
  wd1 = add (al[1], al[1]);
  wd1 = add (wd1, wd1);
  wd2 = (sg0 == sg1) ? sub (0, wd1) : add (0, wd1);
  wd2 = shr (wd2, 7);
  wd3 = (sg0 == sg2) ? 128 : -128;
  wd4 = add (wd2, wd3);
  wd5 = mult (al[2], 32512);
  apl2 = add (wd4, wd5);
  apl2 = (apl2 > 0) ? ((apl2 > 12288) ? 12288 : apl2) : 
                      ((apl2 < -12288) ? -12288 : apl2);
  al[2] = apl2;
}
/* ..................... End of uppol2() ..................... */


/*___________________________________________________________________________
                                                                            
    Function Name : upzero                                                  
                                                                            
    Purpose :                                                               
                                                                            
     .                  
                                                                            
    Inputs :                                                                
                                                                            
                                                                            
    Outputs :                                                               
                                                                            
     none                                                                   
                                                                            
    Return Value :                                                          
     None.                                                                  
                                                                            
 ___________________________________________________________________________
*/
void 
upzero (dlt, bl)
Word16 dlt [];
Word16 bl [];
{

  Word16          sg0, sgi, wd1, wd2, wd3;
  Word16          i;

  /* shift of the dlt line signal and update of bl */

  wd1 = (dlt[0] == 0) ? 0 : 128;
  sg0 = shr (dlt[0], 15);

  for (i = 6; i > 0; i--)
  {
    sgi = shr (dlt[i], 15);
    wd2 = (sg0 == sgi) ? add (0, wd1) : sub (0, wd1);
    wd3 = mult (bl[i], 32640);
    bl[i] = add (wd2, wd3);
    dlt[i] = dlt[i - 1];
  }
}
/* ..................... End of upzero() ..................... */


/* **** Coefficients for both transmission and reception QMF **** */
static Word16   coef_qmf[24] =
  {
    3 * 2, -11 * 2, -11 * 2, 53 * 2, 12 * 2, -156 * 2,
    32 * 2, 362 * 2, -210 * 2, -805 * 2, 951 * 2, 3876 * 2,
    3876 * 2, 951 * 2, -805 * 2, -210 * 2, 362 * 2, 32 * 2,
    -156 * 2, 12 * 2, 53 * 2, -11 * 2, -11 * 2, 3 * 2};
/* ..................... End of table coef_qmf[] ..................... */


/*___________________________________________________________________________
                                                                            
    Function Name : qmf_tx                                                  
                                                                            
    Purpose :                                                               
                                                                            
     G722 QMF analysis (encoder) filter. Uses coefficients in array         
     coef_qmf[] defined above.                                              
                                                                            
    Inputs :                                                                
     xin0 - first sample for the QMF filter (read-only)                     
     xin1 - secon sample for the QMF filter (read-only)                     
     xl   - lower band portion of samples xin0 and xin1 (write-only)        
     xh   - higher band portion of samples xin0 and xin1 (write-only)       
     s    - pointer to state variable structure (read/write)                
                                                                            
    Return Value :                                                          
     None.                                                                  
 ___________________________________________________________________________
*/
#define delayx s->qmf_tx_delayx
void 
qmf_tx (xin0, xin1, xl, xh, s)
Word16 xin0;
Word16 xin1;
Word16 *xl;
Word16 *xh;
g722_state *s;
{

  /* Local variables */
  int             i, j;
  Word32          accuma, accumb;
  Word32          comp_low, comp_high;

  /* Variable initialization */
  if (s->init_qmf_tx == 0)
  {
    s->init_qmf_tx = 1;
    for (j = 0; j < 24; j++)
    {
      delayx[j] = 0;
    }
  }

  /* Saving past samples in delay line */
  delayx[1] = xin1;
  delayx[0] = xin0;

  /* QMF filtering */
  accuma = 0L;
  accumb = 0L;

  for (i = 0, j = 0; i < 12; i++)
  {
    accuma = accuma + (Word32) coef_qmf[j] * delayx[j];
    j++;
    accumb = accumb + (Word32) coef_qmf[j] * delayx[j];
    j++;
  }

  /* Descaling and shift of the delay line */
  for (j = 0; j < 22; j++)
  {
    delayx[23 - j] = delayx[21 - j];
  }

  comp_low = L_add (accuma, accumb);
  comp_low = L_add (comp_low, comp_low);
  comp_high = L_add (accuma, (-accumb));
  comp_high = L_add (comp_high, comp_high);
  *xl = limit ((Word16) L_shr (comp_low, (Word16) 16));
  *xh = limit ((Word16) L_shr (comp_high, (Word16) 16));
}
#undef delayx
/* ..................... End of qmf_tx() ..................... */


/*___________________________________________________________________________
                                                                            
    Function Name : qmf_rx                                                  
                                                                            
     G722 QMF synthesis (decoder) filter. Uses coefficients in array        
     coef_qmf[] defined above.                                              
                                                                            
    Inputs :                                                                
     xout0 - first sample out of the QMF filter (write-only)                
     xout1 - secon sample out of the QMF filter (write-only)                
     rl    - lower band portion of a sample (read-only)                     
     rh    - higher band portion of a sample (read-only)                    
     s     - pointer to state variable structure (read/write)               
                                                                            
    Return Value :                                                          
     None.                                                                  
 ___________________________________________________________________________
*/
#define delayx s->qmf_rx_delayx
void 
qmf_rx (rl, rh, xout1, xout2, s)
Word16 rl;
Word16 rh;
Word16 *xout1;
Word16 *xout2;
g722_state *s;
{

  /* definition of the local variables */
  int             i, j;
  Word32          accuma, accumb;
  Word32          comp_low, comp_high;
  Word16          xd, xs;

  /* initialisation des variables */

  if (s->init_qmf_rx == 0)
  {
    s->init_qmf_rx = 1;
    for (j = 0; j < 24; j++)
    {
      delayx[j] = 0;
    }
  }

  /* calcul de xs et xd