ref: 381a7bd0e2bbe4838cc59f9220eaecaa46b6a303
dir: /src/biquad.h/
/* libSoX Biquad filter common definitions (c) 2006-7 robs@users.sourceforge.net
*
* This library is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation; either version 2.1 of the License, or (at
* your option) any later version.
*
* This library 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 Lesser
* General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this library; if not, write to the Free Software Foundation,
* Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef biquad_included
#define biquad_included
#define LSX_EFF_ALIAS
#include "sox_i.h"
typedef enum {
filter_LPF,
filter_HPF,
filter_BPF_CSG,
filter_BPF,
filter_notch,
filter_APF,
filter_peakingEQ,
filter_lowShelf,
filter_highShelf,
filter_LPF_1,
filter_HPF_1,
filter_BPF_SPK,
filter_BPF_SPK_N,
filter_AP1,
filter_AP2,
filter_deemph,
filter_riaa
} filter_t;
typedef enum {
width_bw_Hz,
width_bw_kHz,
/* The old, non-RBJ, non-freq-warped band-pass/reject response;
* leaving here for now just in case anybody misses it: */
width_bw_old,
width_bw_oct,
width_Q,
width_slope
} width_t;
/* Private data for the biquad filter effects */
typedef struct {
double gain; /* For EQ filters */
double fc; /* Centre/corner/cutoff frequency */
double width; /* Filter width; interpreted as per width_type */
width_t width_type;
filter_t filter_type;
double b0, b1, b2; /* Filter coefficients */
double a0, a1, a2; /* Filter coefficients */
sox_sample_t i1, i2; /* Filter memory */
double o1, o2; /* Filter memory */
} biquad_t;
int lsx_biquad_getopts(sox_effect_t * effp, int n, char **argv,
int min_args, int max_args, int fc_pos, int width_pos, int gain_pos,
char const * allowed_width_types, filter_t filter_type);
int lsx_biquad_start(sox_effect_t * effp);
int lsx_biquad_flow(sox_effect_t * effp, const sox_sample_t *ibuf, sox_sample_t *obuf,
size_t *isamp, size_t *osamp);
#endif