various math functions More...
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Enumerations | |
| enum | aubio_window_type { 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 } |
Window types. More... | |
Functions | |
| void | aubio_window (smpl_t *w, uint_t size, aubio_window_type wintype) |
| create window | |
| smpl_t | aubio_unwrap2pi (smpl_t phase) |
| principal argument | |
| smpl_t | vec_mean (fvec_t *s) |
| calculates the mean of a vector | |
| smpl_t | vec_max (fvec_t *s) |
| returns the max of a vector | |
| smpl_t | vec_min (fvec_t *s) |
| returns the min of a vector | |
| uint_t | vec_min_elem (fvec_t *s) |
| returns the index of the min of a vector | |
| uint_t | vec_max_elem (fvec_t *s) |
| returns the index of the max of a vector | |
| void | vec_shift (fvec_t *s) |
| implement 'fftshift' like function | |
| smpl_t | vec_sum (fvec_t *s) |
| returns sum | |
| smpl_t | vec_local_energy (fvec_t *f) |
| returns energy | |
| smpl_t | vec_local_hfc (fvec_t *f) |
| returns High Frequency Energy Content | |
| smpl_t | vec_alpha_norm (fvec_t *DF, smpl_t alpha) |
| return alpha norm. | |
| void | vec_dc_removal (fvec_t *mag) |
| dc(min) removal | |
| void | vec_alpha_normalise (fvec_t *mag, uint_t alpha) |
| alpha normalisation | |
| void | vec_add (fvec_t *mag, smpl_t threshold) |
| add a constant to all members of a vector | |
| void | vec_adapt_thres (fvec_t *vec, fvec_t *tmp, uint_t win_post, uint_t win_pre) |
| compute adaptive threshold of input vector | |
| smpl_t | vec_moving_thres (fvec_t *vec, fvec_t *tmp, uint_t win_post, uint_t win_pre, uint_t win_pos) |
| adaptative thresholding | |
| smpl_t | vec_median (fvec_t *input) |
| returns the median of the vector | |
| smpl_t | vec_quadint (fvec_t *x, uint_t pos) |
| finds exact maximum position by quadratic interpolation | |
| smpl_t | vec_quadint_min (fvec_t *x, uint_t pos, uint_t span) |
| finds exact minimum position by quadratic interpolation | |
| smpl_t | aubio_quadfrac (smpl_t s0, smpl_t s1, smpl_t s2, smpl_t pf) |
| Quadratic interpolation using Lagrange polynomial. | |
| uint_t | vec_peakpick (fvec_t *input, uint_t pos) |
| returns 1 if X1 is a peak and positive | |
| smpl_t | aubio_bintomidi (smpl_t bin, smpl_t samplerate, smpl_t fftsize) |
| convert frequency bin to midi value | |
| smpl_t | aubio_miditobin (smpl_t midi, smpl_t samplerate, smpl_t fftsize) |
| convert midi value to frequency bin | |
| smpl_t | aubio_bintofreq (smpl_t bin, smpl_t samplerate, smpl_t fftsize) |
| convert frequency bin to frequency (Hz) | |
| smpl_t | aubio_freqtobin (smpl_t freq, smpl_t samplerate, smpl_t fftsize) |
| convert frequency (Hz) to frequency bin | |
| smpl_t | aubio_freqtomidi (smpl_t freq) |
| convert frequency (Hz) to midi value (0-128) | |
| smpl_t | aubio_miditofreq (smpl_t midi) |
| convert midi value (0-128) to frequency (Hz) | |
| uint_t | aubio_silence_detection (fvec_t *ibuf, smpl_t threshold) |
| check if current buffer level is under a given threshold | |
| smpl_t | aubio_level_detection (fvec_t *ibuf, smpl_t threshold) |
| get the current buffer level | |
| void | aubio_autocorr (fvec_t *input, fvec_t *output) |
| calculate normalised autocorrelation function | |
| void | aubio_cleanup (void) |
| clean up cached memory at the end of program | |
various math functions
| enum aubio_window_type |
Window types.
inspired from
| void aubio_cleanup | ( | void | ) |
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.
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
| s0,s1,s2 | are 3 known points on the curve, |
| pf | is the floating point index [0;2] |
return alpha norm.
alpha=2 means normalise variance. alpha=1 means normalise abs value. as alpha goes large, tends to normalisation by max value.
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_moving_thres | ( | fvec_t * | vec, |
| fvec_t * | tmp, | ||
| uint_t | win_post, | ||
| uint_t | win_pre, | ||
| uint_t | win_pos | ||
| ) |
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
| void vec_shift | ( | 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]
1.7.2
