filter.h

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

    iLBC Speech Coder ANSI-C Source Code

    filter.h

    Copyright (C) The Internet Society (2004). 
    All Rights Reserved.

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

#ifndef __iLBC_FILTER_H
#define __iLBC_FILTER_H

void AllPoleFilter(
    float *InOut,   /* (i/o) on entrance InOut[-orderCoef] to 
                           InOut[-1] contain the state of the 
                           filter (delayed samples). InOut[0] to 
                           InOut[lengthInOut-1] contain the filter 
                           input, on en exit InOut[-orderCoef] to 
                           InOut[-1] is unchanged and InOut[0] to 
                           InOut[lengthInOut-1] contain filtered 
                           samples */
    float *Coef,/* (i) filter coefficients, Coef[0] is assumed 
                           to be 1.0 */
    int lengthInOut,/* (i) number of input/output samples */
    int orderCoef   /* (i) number of filter coefficients */
);



void AllZeroFilter(
    float *In,      /* (i) In[0] to In[lengthInOut-1] contain 
                           filter input samples */
    float *Coef,/* (i) filter coefficients (Coef[0] is assumed 
                           to be 1.0) */
    int lengthInOut,/* (i) number of input/output samples */
    int orderCoef,  /* (i) number of filter coefficients */
    float *Out      /* (i/o) on entrance Out[-orderCoef] to Out[-1]
                           contain the filter state, on exit Out[0] 
                           to Out[lengthInOut-1] contain filtered 
                           samples */
);

void ZeroPoleFilter(
    float *In,      /* (i) In[0] to In[lengthInOut-1] contain filter
                           input samples In[-orderCoef] to In[-1] 
                           contain state of all-zero section */
    float *ZeroCoef,/* (i) filter coefficients for all-zero 
                           section (ZeroCoef[0] is assumed to 
                           be 1.0) */
    float *PoleCoef,/* (i) filter coefficients for all-pole section
                           (ZeroCoef[0] is assumed to be 1.0) */
    int lengthInOut,/* (i) number of input/output samples */
    int orderCoef,  /* (i) number of filter coefficients */
    float *Out      /* (i/o) on entrance Out[-orderCoef] to Out[-1]
                           contain state of all-pole section. On
                           exit Out[0] to Out[lengthInOut-1] 
                           contain filtered samples */
);

void DownSample (
    float  *In,     /* (i) input samples */
    float  *Coef,   /* (i) filter coefficients */
    int lengthIn,   /* (i) number of input samples */ 
    float  *state,  /* (i) filter state */
    float  *Out     /* (o) downsampled output */
);

#endif