ref: 55ed67a6dbdddc1a12912db6aac3534be698e25f
dir: /src/temporal/filter.h/
/*
Copyright (C) 2003 Paul Brossier
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
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. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#ifndef FILTER_H
#define FILTER_H
/** \file
Infinite Impulse Response filter
This file implements IIR filters of any order:
\f$ y[n] = b_1 x[n] + ... + b_{order} x[n-order] -
a_2 y[n-1] - ... - a_{order} y[n-order]\f$
The filtfilt version runs the filter twice, forward and backward, to
compensate the phase shifting of the forward operation.
*/
#ifdef __cplusplus
extern "C" {
#endif
/** IIR filter object */
typedef struct _aubio_filter_t aubio_filter_t;
/** filter input vector (in-place)
\param b biquad object as returned by new_aubio_biquad
\param in input vector to filter
*/
void aubio_filter_do(aubio_filter_t * b, fvec_t * in);
/** filter input vector (out-of-place)
\param b biquad object as returned by new_aubio_biquad
\param in input vector to filter
\param out output vector to store filtered input
*/
void aubio_filter_do_outplace(aubio_filter_t * b, fvec_t * in, fvec_t * out);
/** filter input vector forward and backward
\param b biquad object as returned by new_aubio_biquad
\param in input vector to filter
\param tmp memory space to use for computation
*/
void aubio_filter_do_filtfilt(aubio_filter_t * b, fvec_t * in, fvec_t * tmp);
/** create new IIR filter
\param samplerate signal sampling rate
\param order order of the filter (number of coefficients)
\param channels number of channels to allocate
*/
aubio_filter_t * new_aubio_filter(uint_t samplerate, uint_t order, uint_t channels);
/** delete a filter object
\param f filter object to delete
*/
void del_aubio_filter(aubio_filter_t * f);
#ifdef __cplusplus
}
#endif
#endif /*FILTER_H*/