71 lines
1.7 KiB
C
71 lines
1.7 KiB
C
|
/*
|
||
|
|
* iLBC - a library for the iLBC codec
|
||
|
|
*
|
||
|
|
* hpInput.c - The iLBC low bit rate speech codec.
|
||
|
|
*
|
||
|
|
* Adapted by Steve Underwood <steveu@coppice.org> from the reference
|
||
|
|
* iLBC code supplied in RFC3951.
|
||
|
|
*
|
||
|
|
* Original code Copyright (C) The Internet Society (2004).
|
||
|
|
* All changes to produce this version Copyright (C) 2008 by Steve Underwood
|
||
|
|
* All Rights Reserved.
|
||
|
|
*
|
||
|
|
* This program is distributed in the hope that it will be useful,
|
||
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
|
||
|
|
*
|
||
|
|
* $Id: hpInput.c,v 1.2 2008/03/06 12:27:38 steveu Exp $
|
||
|
|
*/
|
||
|
|
|
||
|
|
/*! \file */
|
||
|
|
|
||
|
|
#ifdef HAVE_CONFIG_H
|
||
|
|
#include <config.h>
|
||
|
|
#endif
|
||
|
|
|
||
|
|
#include <inttypes.h>
|
||
|
|
|
||
|
|
#include "constants.h"
|
||
|
|
#include "hpInput.h"
|
||
|
|
|
||
|
|
/*----------------------------------------------------------------*
|
||
|
|
* Input high-pass filter
|
||
|
|
*---------------------------------------------------------------*/
|
||
|
|
|
||
|
|
void hpInput(const 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;
|
||
|
|
const float *pi;
|
||
|
|
float *po;
|
||
|
|
|
||
|
|
/* all-zero section*/
|
||
|
|
pi = &In[0];
|
||
|
|
po = &Out[0];
|
||
|
|
for (i = 0; i < len; i++)
|
||
|
|
{
|
||
|
|
*po = hpi_zero_coefsTbl[0]*(*pi);
|
||
|
|
*po += hpi_zero_coefsTbl[1]*mem[0];
|
||
|
|
*po += hpi_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 -= hpi_pole_coefsTbl[1]*mem[2];
|
||
|
|
*po -= hpi_pole_coefsTbl[2]*mem[3];
|
||
|
|
|
||
|
|
mem[3] = mem[2];
|
||
|
|
mem[2] = *po;
|
||
|
|
po++;
|
||
|
|
}
|
||
|
|
}
|