Mercurial > hg > audio-file-loader
diff libs/aubioFullOSXUni/include/aubio/biquad.h @ 0:bcb0d40158f4
started audio file loader project - using oF_061
author | Andrew N Robertson <andrew.robertson@eecs.qmul.ac.uk> |
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date | Tue, 30 Aug 2011 20:18:34 +0100 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/libs/aubioFullOSXUni/include/aubio/biquad.h Tue Aug 30 20:18:34 2011 +0100 @@ -0,0 +1,80 @@ +/* + 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 BIQUAD_H +#define BIQUAD_H + +/** \file + + Second order Infinite Impulse Response filter + + This file implements a normalised biquad filter (second order IIR): + + \f$ y[n] = b_1 x[n] + b_2 x[n-1] + b_3 x[n-2] - a_2 y[n-1] - a_3 y[n-2] \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 + +/** biquad filter object */ +typedef struct _aubio_biquad_t aubio_biquad_t; + +/** filter input vector + + \param b biquad object as returned by new_aubio_biquad + \param in input vector to filter + +*/ +void aubio_biquad_do(aubio_biquad_t * b, fvec_t * in); +/** 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_biquad_do_filtfilt(aubio_biquad_t * b, fvec_t * in, fvec_t * tmp); +/** create new biquad filter + + \param b1 forward filter coefficient + \param b2 forward filter coefficient + \param b3 forward filter coefficient + \param a2 feedback filter coefficient + \param a3 feedback filter coefficient + +*/ +aubio_biquad_t * new_aubio_biquad(lsmp_t b1, lsmp_t b2, lsmp_t b3, lsmp_t a2, lsmp_t a3); + +/** delete biquad filter + + \param b biquad object to delete + +*/ +void del_aubio_biquad(aubio_biquad_t * b); + +#ifdef __cplusplus +} +#endif + +#endif /*BIQUAD_H*/