/* Copyright (C) 2003-2009 Paul Brossier This file is part of aubio. aubio 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 3 of the License, or (at your option) any later version. aubio 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 aubio. If not, see . */ /** @file * various math functions * * \todo multichannel (each function should return -or set- an array sized to * the number of channel in the input vector) * * \todo appropriate switches depending on types.h content */ #ifndef MATHUTILS_H #define MATHUTILS_H #ifdef __cplusplus extern "C" { #endif /** Window types * * inspired from * * - dafx : http://profs.sci.univr.it/%7Edafx/Final-Papers/ps/Bernardini.ps.gz * - freqtweak : http://freqtweak.sf.net/ * - extace : http://extace.sf.net/ */ typedef enum { aubio_win_rectangle, aubio_win_hamming, aubio_win_hanning, aubio_win_hanningz, aubio_win_blackman, aubio_win_blackman_harris, aubio_win_gaussian, aubio_win_welch, aubio_win_parzen } aubio_window_type; /** create window */ fvec_t * new_aubio_window(uint_t size, aubio_window_type wintype); /** principal argument * * mod(phase+PI,-TWO_PI)+PI */ smpl_t aubio_unwrap2pi (smpl_t phase); /** calculates the mean of a vector * * \bug mono */ smpl_t vec_mean(fvec_t *s); /** returns the max of a vector * * \bug mono */ smpl_t vec_max(fvec_t *s); /** returns the min of a vector * * \bug mono */ smpl_t vec_min(fvec_t *s); /** returns the index of the min of a vector * * \bug mono */ uint_t vec_min_elem(fvec_t *s); /** returns the index of the max of a vector * * \bug mono */ uint_t vec_max_elem(fvec_t *s); /** implement 'fftshift' like function * * a[0]...,a[n/2],a[n/2+1],...a[n] * * becomes * * a[n/2+1],...a[n],a[0]...,a[n/2] */ void vec_shift(fvec_t *s); /** returns sum */ smpl_t vec_sum(fvec_t *s); /** returns energy * * \bug mono */ smpl_t vec_local_energy(fvec_t * f); /** returns High Frequency Energy Content * * \bug mono */ smpl_t vec_local_hfc(fvec_t * f); /** return alpha norm. * * alpha=2 means normalise variance. * alpha=1 means normalise abs value. * as alpha goes large, tends to normalisation * by max value. * * \bug should not use POW :( */ smpl_t vec_alpha_norm(fvec_t * DF, smpl_t alpha); /** dc(min) removal */ void vec_dc_removal(fvec_t * mag); /** alpha normalisation */ void vec_alpha_normalise(fvec_t * mag, uint_t alpha); /** add a constant to all members of a vector */ void vec_add(fvec_t * mag, smpl_t threshold); /** compute adaptive threshold of input vector */ void vec_adapt_thres(fvec_t * vec, fvec_t * tmp, uint_t win_post, uint_t win_pre); /** adaptative thresholding * * y=fn_thresh(fn,x,post,pre) * compute adaptive threshold at each time * fn : a function name or pointer, eg 'median' * x: signal vector * post: window length, causal part * pre: window length, anti-causal part * Returns: * y: signal the same length as x * * Formerly median_thresh, used compute median over a * window of post+pre+1 samples, but now works with any * function that takes a vector or matrix and returns a * 'representative' value for each column, eg * medians=fn_thresh(median,x,8,8) * minima=fn_thresh(min,x,8,8) * see SPARMS for explanation of post and pre */ smpl_t vec_moving_thres(fvec_t * vec, fvec_t * tmp, uint_t win_post, uint_t win_pre, uint_t win_pos); /** returns the median of the vector * * This Quickselect routine is based on the algorithm described in * "Numerical recipes in C", Second Edition, * Cambridge University Press, 1992, Section 8.5, ISBN 0-521-43108-5 * * This code by Nicolas Devillard - 1998. Public domain, * available at http://ndevilla.free.fr/median/median/ */ smpl_t vec_median(fvec_t * input); /** finds exact peak index by quadratic interpolation*/ smpl_t vec_quadint(fvec_t * x, uint_t pos, uint_t span); /** Quadratic interpolation using Lagrange polynomial. * * inspired from ``Comparison of interpolation algorithms in real-time sound * processing'', Vladimir Arnost, * * estimate = s0 + (pf/2.)*((pf-3.)*s0-2.*(pf-2.)*s1+(pf-1.)*s2); * where * \param s0,s1,s2 are 3 known points on the curve, * \param pf is the floating point index [0;2] */ smpl_t aubio_quadfrac(smpl_t s0, smpl_t s1, smpl_t s2, smpl_t pf); /** returns 1 if X1 is a peak and positive */ uint_t vec_peakpick(fvec_t * input, uint_t pos); /** convert frequency bin to midi value */ smpl_t aubio_bintomidi(smpl_t bin, smpl_t samplerate, smpl_t fftsize); /** convert midi value to frequency bin */ smpl_t aubio_miditobin(smpl_t midi, smpl_t samplerate, smpl_t fftsize); /** convert frequency bin to frequency (Hz) */ smpl_t aubio_bintofreq(smpl_t bin, smpl_t samplerate, smpl_t fftsize); /** convert frequency (Hz) to frequency bin */ smpl_t aubio_freqtobin(smpl_t freq, smpl_t samplerate, smpl_t fftsize); /** convert frequency (Hz) to midi value (0-128) */ smpl_t aubio_freqtomidi(smpl_t freq); /** convert midi value (0-128) to frequency (Hz) */ smpl_t aubio_miditofreq(smpl_t midi); /** check if current buffer level is under a given threshold */ uint_t aubio_silence_detection(fvec_t * ibuf, smpl_t threshold); /** get the current buffer level */ smpl_t aubio_level_detection(fvec_t * ibuf, smpl_t threshold); /** * calculate normalised autocorrelation function */ void aubio_autocorr(fvec_t * input, fvec_t * output); /** * zero-crossing rate (number of zero cross per sample) */ smpl_t aubio_zero_crossing_rate(fvec_t * input); /** * clean up cached memory at the end of program * * use this function at the end of programs to purge all * cached memory. so far this function is only used to clean * fftw cache. */ void aubio_cleanup(void); #ifdef __cplusplus } #endif #endif