1 /* SoX Resampler Library Copyright (c) 2007-13 robs@users.sourceforge.net 2 * Licence for this file: LGPL v2.1 See LICENCE for details. */ 3 4 #if !defined soxr_filter_included 5 #define soxr_filter_included 6 7 #include "aliases.h" 8 9 double lsx_bessel_I_0(double x); 10 void lsx_init_fft_cache(void); 11 void lsx_clear_fft_cache(void); 12 void lsx_init_fft_cache_f(void); 13 void lsx_clear_fft_cache_f(void); 14 #define lsx_is_power_of_2(x) !(x < 2 || (x & (x - 1))) 15 void lsx_safe_rdft(int len, int type, double * d); 16 void lsx_safe_cdft(int len, int type, double * d); 17 void lsx_safe_rdft_f(int len, int type, float * d); 18 void lsx_safe_cdft_f(int len, int type, float * d); 19 void lsx_ordered_convolve(int n, void * not_used, double * a, const double * b); 20 void lsx_ordered_convolve_f(int n, void * not_used, float * a, const float * b); 21 void lsx_ordered_partial_convolve(int n, double * a, const double * b); 22 void lsx_ordered_partial_convolve_f(int n, float * a, const float * b); 23 24 double lsx_kaiser_beta(double att, double tr_bw); 25 double * lsx_make_lpf(int num_taps, double Fc, double beta, double rho, 26 double scale); 27 void lsx_kaiser_params(double att, double Fc, double tr_bw, double * beta, int * num_taps); 28 double * lsx_design_lpf( 29 double Fp, /* End of pass-band */ 30 double Fs, /* Start of stop-band */ 31 double Fn, /* Nyquist freq; e.g. 0.5, 1, PI; < 0: dummy run */ 32 double att, /* Stop-band attenuation in dB */ 33 int * num_taps, /* 0: value will be estimated */ 34 int k, /* >0: number of phases; <0: num_taps = 1 (mod -k) */ 35 double beta); /* <0: value will be estimated */ 36 37 void lsx_fir_to_phase(double * * h, int * len, 38 int * post_len, double phase0); 39 40 double lsx_f_resp(double t, double a); 41 double lsx_inv_f_resp(double drop, double a); 42 #define lsx_to_3dB(a) (1 - lsx_inv_f_resp(-3., a)) 43 44 #endif 45