asterisk/codecs/ilbc/hpOutput.c

 
/****************************************************************** 
 
    iLBC Speech Coder ANSI-C Source Code 
 
    hpOutput.c  
 
    Copyright (c) 2001, 
    Global IP Sound AB. 
    All rights reserved. 
 
******************************************************************/ 
 
#include "constants.h" 
#include "hpOutput.h"
 
/*----------------------------------------------------------------* 
 *  Output high-pass filter                           
 *---------------------------------------------------------------*/ 
 
void hpOutput( 
    float *In,  /* (i) vector to filter */ 
    int len,/* (i) length of vector to filter */ 
    float *Out, /* (o) the resulting filtered vector */ 
    float *mem  /* (i/o) the filter state */ 
){ 
    int i; 
    float *pi, *po; 
 
    /* all-zero section*/ 
 
    pi = &In[0]; 
    po = &Out[0]; 
    for (i=0; i<len; i++) { 
        *po = hpo_zero_coefsTbl[0] * (*pi); 
        *po += hpo_zero_coefsTbl[1] * mem[0]; 
        *po += hpo_zero_coefsTbl[2] * mem[1]; 
 
        mem[1] = mem[0]; 
        mem[0] = *pi; 
        po++; 
        pi++; 
 
    } 
 
    /* all-pole section*/ 
 
    po = &Out[0]; 
    for (i=0; i<len; i++) { 
        *po -= hpo_pole_coefsTbl[1] * mem[2]; 
        *po -= hpo_pole_coefsTbl[2] * mem[3]; 
 
        mem[3] = mem[2]; 
        mem[2] = *po; 
        po++; 
    } 
}