boo/soxr/src/filter.h

40 lines
1.7 KiB
C

/* SoX Resampler Library Copyright (c) 2007-13 robs@users.sourceforge.net
* Licence for this file: LGPL v2.1 See LICENCE for details. */
#if !defined soxr_filter_included
#define soxr_filter_included
#include "aliases.h"
double lsx_bessel_I_0(double x);
void lsx_init_fft_cache(void);
void lsx_clear_fft_cache(void);
void lsx_init_fft_cache_f(void);
void lsx_clear_fft_cache_f(void);
#define lsx_is_power_of_2(x) !(x < 2 || (x & (x - 1)))
void lsx_safe_rdft(int len, int type, double * d);
void lsx_safe_cdft(int len, int type, double * d);
void lsx_safe_rdft_f(int len, int type, float * d);
void lsx_safe_cdft_f(int len, int type, float * d);
void lsx_ordered_convolve(int n, void * not_used, double * a, const double * b);
void lsx_ordered_convolve_f(int n, void * not_used, float * a, const float * b);
void lsx_ordered_partial_convolve(int n, double * a, const double * b);
void lsx_ordered_partial_convolve_f(int n, float * a, const float * b);
double lsx_kaiser_beta(double att, double tr_bw);
double * lsx_make_lpf(int num_taps, double Fc, double beta, double rho,
double scale);
void lsx_kaiser_params(double att, double Fc, double tr_bw, double * beta, int * num_taps);
double * lsx_design_lpf(
double Fp, /* End of pass-band */
double Fs, /* Start of stop-band */
double Fn, /* Nyquist freq; e.g. 0.5, 1, PI; < 0: dummy run */
double att, /* Stop-band attenuation in dB */
int * num_taps, /* 0: value will be estimated */
int k, /* >0: number of phases; <0: num_taps ≡ 1 (mod -k) */
double beta); /* <0: value will be estimated */
void lsx_fir_to_phase(double * * h, int * len,
int * post_len, double phase0);
#endif