Mercurial > hg > python-tutorial-skeleton
view signal_processing.py @ 3:4be70944d21b skeleton_v2
Add some basic signal processing methods we need
author | Chris Cannam |
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date | Thu, 04 Oct 2012 17:14:05 +0100 |
parents | |
children | ea2387fd1b90 |
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import numpy as np def rms(samples): """Return the root mean square of the given samples""" return np.sqrt(np.mean(np.array(samples)**2)) def autocorrelation(samples): """Return the autocorrelation of the given samples, as an array with zero lag at the start""" acf = np.correlate(samples, samples, mode='full') return acf[len(acf)/2:] def bpm_to_lag(bpm, hops_per_sec): """Return the autocorrelation lag corresponding to the duration of a beat at the given tempo in bpm""" return int((60.0 / bpm) * hops_per_sec) def lag_to_bpm(lag, hops_per_sec): """Return the tempo in bpm whose beat duration corresponds to the given autocorrelation lag""" return (60.0 * hops_per_sec) / lag