anaFilter.h File Reference

This graph shows which files directly or indirectly include this file:

Go to the source code of this file.

Functions
void	anaFilter (float *In, float *a, int len, float *Out, float *mem)

Function Documentation

anaFilter()

void anaFilter	(	float *	In,
		float *	a,
		int	len,
		float *	Out,
		float *	mem
	)

Definition at line 20 of file anaFilter.c.

References a, len(), and LPC_FILTERORDER.

Referenced by iLBC_encode().

    {
       int i, j;
       float *po, *pi, *pm, *pa;

       po = Out;

       /* Filter first part using memory from past */

       for (i=0; i<LPC_FILTERORDER; i++) {
           pi = &In[i];
           pm = &mem[LPC_FILTERORDER-1];
           pa = a;
           *po=0.0;





           for (j=0; j<=i; j++) {
               *po+=(*pa++)*(*pi--);
           }
           for (j=i+1; j<LPC_FILTERORDER+1; j++) {

               *po+=(*pa++)*(*pm--);
           }
           po++;
       }

       /* Filter last part where the state is entirely
          in the input vector */

       for (i=LPC_FILTERORDER; i<len; i++) {
           pi = &In[i];
           pa = a;
           *po=0.0;
           for (j=0; j<LPC_FILTERORDER+1; j++) {
               *po+=(*pa++)*(*pi--);
           }
           po++;
       }

       /* Update state vector */

       memcpy(mem, &In[len-LPC_FILTERORDER],
           LPC_FILTERORDER*sizeof(float));
   }