| 1 | #! /usr/bin/env python |
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| 2 | |
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| 3 | from aubio import filterbank, fvec |
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| 4 | from pylab import loglog, show, subplot, xlim, ylim, xlabel, ylabel, title |
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| 5 | from numpy import vstack, arange |
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| 6 | |
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| 7 | win_s = 2048 |
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| 8 | samplerate = 48000 |
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| 9 | |
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| 10 | freq_list = [60, 80, 200, 400, 800, 1600, 3200, 6400, 12800, 24000] |
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| 11 | n_filters = len(freq_list) - 2 |
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| 12 | |
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| 13 | f = filterbank(n_filters, win_s) |
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| 14 | freqs = fvec(freq_list) |
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| 15 | f.set_triangle_bands(freqs, samplerate) |
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| 16 | |
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| 17 | subplot(211) |
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| 18 | title('Examples of filterbank built with set_triangle_bands and set_coeffs') |
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| 19 | times = vstack([arange(win_s / 2 + 1) * samplerate / win_s] * n_filters) |
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| 20 | loglog(times.T, f.get_coeffs().T, '.-') |
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| 21 | xlim([50, samplerate/2]) |
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| 22 | ylim([1.0e-6, 2.0e-2]) |
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| 23 | ylabel('Amplitude') |
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| 24 | |
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| 25 | ## build a new filterbank |
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| 26 | |
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| 27 | freq_list = [60, 80, 200, 400, 800, 1200, 1600, 3200, 6400, 10000, 15000, 24000] |
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| 28 | n_filters = len(freq_list) - 2 |
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| 29 | |
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| 30 | f = filterbank(n_filters, win_s) |
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| 31 | freqs = fvec(freq_list) |
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| 32 | f.set_triangle_bands(freqs, samplerate) |
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| 33 | |
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| 34 | coeffs = f.get_coeffs() |
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| 35 | coeffs[4] *= 5. |
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| 36 | |
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| 37 | f.set_coeffs(coeffs) |
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| 38 | |
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| 39 | subplot(212) |
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| 40 | times = vstack([arange(win_s / 2 + 1) * samplerate / win_s] * n_filters) |
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| 41 | loglog(times.T, f.get_coeffs().T, '.-') |
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| 42 | xlim([50, samplerate/2]) |
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| 43 | ylim([1.0e-6, 2.0e-2]) |
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| 44 | xlabel('Frequency (Hz)') |
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| 45 | ylabel('Amplitude') |
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| 46 | |
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| 47 | show() |
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