 Timestamp:
 Nov 4, 2018, 9:00:31 PM (20 months ago)
 Branches:
 feature/autosink, feature/constantq, feature/pitchshift, feature/pydocstrings, feature/timestretch, master
 Children:
 5f2f459
 Parents:
 254acce
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python/demos/demo_filterbank.py
r254acce reff63ab 1 1 #! /usr/bin/env python 2 2 3 from aubio import filterbank, fvec 4 from pylab import loglog, show, xlim, ylim, xlabel, ylabel, title 5 from numpy import vstack, arange 3 """Create a filterbank from a list of frequencies. 6 4 5 This demo uses `aubio.filterbank.set_triangle_bands` to build a set of 6 triangular filters from a list of frequencies. 7 8 The filterbank coefficients are then modified before being displayed.""" 9 10 import aubio 11 import numpy as np 12 import matplotlib.pyplot as plt 13 14 # sampling rate and size of the fft 15 samplerate = 48000 7 16 win_s = 2048 8 samplerate = 480009 17 18 # define a list of custom frequency 10 19 freq_list = [60, 80, 200, 400, 800, 1600, 3200, 6400, 12800, 24000] 20 # number of filters to create 11 21 n_filters = len(freq_list)  2 12 22 13 f = filterbank(n_filters, win_s) 14 freqs = fvec(freq_list) 23 # create a new filterbank 24 f = aubio.filterbank(n_filters, win_s) 25 freqs = aubio.fvec(freq_list) 15 26 f.set_triangle_bands(freqs, samplerate) 16 27 28 # get the coefficients from the filterbank 17 29 coeffs = f.get_coeffs() 18 coeffs[4] *= 5. 19 30 # apply a gain to fifth band 31 coeffs[4] *= 6. 32 # load the modified coeffs into the filterbank 20 33 f.set_coeffs(coeffs) 21 34 22 times = vstack([arange(win_s // 2 + 1) * samplerate / win_s] * n_filters) 23 title('Bank of filters built using a simple list of boundaries\nThe middle band has been amplified by 2.') 24 loglog(times.T, f.get_coeffs().T, '.') 25 xlim([50, samplerate/2]) 26 ylim([1.0e6, 2.0e2]) 27 xlabel('log frequency (Hz)') 28 ylabel('log amplitude') 29 30 show() 35 # display the band gains in a loglog plot 36 freqs = np.vstack([np.arange(win_s // 2 + 1) * samplerate / win_s] * n_filters) 37 plt.title('filterbank built from a list of frequencies\n' 38 'The 5th band has been amplified by a factor 6.') 39 plt.loglog(freqs.T, f.get_coeffs().T, '.') 40 plt.xlim([50, samplerate/2]) 41 plt.ylim([1.0e6, 2.0e2]) 42 plt.xlabel('log frequency (Hz)') 43 plt.ylabel('log amplitude') 44 plt.show()
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