ref: 735a7394485494e3064f653c2096576d2db4b0d2
parent: acd97d1038823180179882ebb3d3dc72da0fd3e3
author: Paul Brossier <piem@piem.org>
date: Tue Oct 15 19:22:00 EDT 2013
python/demos/demo_filterbank.py: added simple filterbank demo
--- /dev/null
+++ b/python/demos/demo_filterbank.py
@@ -1,0 +1,30 @@
+#! /usr/bin/python
+
+from aubio import filterbank, fvec
+from pylab import loglog, show, subplot, xlim, ylim, xlabel, ylabel, title
+from numpy import vstack, arange
+
+win_s = 2048
+samplerate = 48000
+
+freq_list = [60, 80, 200, 400, 800, 1600, 3200, 6400, 12800, 24000]
+n_filters = len(freq_list) - 2
+
+f = filterbank(n_filters, win_s)
+freqs = fvec(freq_list)
+f.set_triangle_bands(freqs, samplerate)
+
+coeffs = f.get_coeffs()
+coeffs[4] *= 5.
+
+f.set_coeffs(coeffs)
+
+times = vstack([arange(win_s / 2 + 1) * samplerate / win_s] * n_filters)
+title('Bank of filters built using a simple list of boundaries\nThe middle band has been amplified by 2.')+loglog(times.T, f.get_coeffs().T, '.-')
+xlim([50, samplerate/2])
+ylim([1.0e-6, 2.0e-2])
+xlabel('log frequency (Hz)')+ylabel('log amplitude')+
+show()