demo_filterbank*.py: improved

diff --git a/interfaces/python/demo_filterbank.py b/interfaces/python/demo_filterbank.py
deleted file mode 100755 (executable)
index 1b90ad3..0000000
--- a/interfaces/python/demo_filterbank.py
+++ /dev/null
@@ -1,16 +0,0 @@
-#! /usr/bin/python
-
-try:
-  from aubio import filterbank, fvec
-except ImportError:
-  import localaubio
-  from aubio import filterbank, fvec
-
-f = filterbank(9, 1024)
-freq_list = [60, 80, 200, 400, 800, 1600, 3200, 6400, 12800, 15000, 24000]
-freqs = fvec(freq_list)
-f.set_triangle_bands(freqs, 48000)
-
-from pylab import loglog, show
-loglog(f.get_coeffs().T, '+-')
-show()

diff --git a/interfaces/python/demo_filterbank_slaney.py b/interfaces/python/demo_filterbank_slaney.py
new file mode 100755 (executable)
index 0000000..6ed7fd5
--- /dev/null
+++ b/interfaces/python/demo_filterbank_slaney.py
@@ -0,0 +1,23 @@
+#! /usr/bin/python
+
+from aubio import filterbank
+from numpy import array, arange, vstack
+
+win_s = 8192
+samplerate = 16000
+
+f = filterbank(40, win_s)
+f.set_mel_coeffs_slaney(samplerate)
+
+from pylab import loglog, title, show, xlim, ylim, xlabel, ylabel
+xlim([0,samplerate / 2])
+print f.get_coeffs().shape
+times = vstack([arange(win_s / 2 + 1) * samplerate / win_s] * 40)
+print times.shape
+loglog(times.T, f.get_coeffs().T, '.-')
+title('Mel frequency bands coefficients')
+xlim([100, 7500])
+ylim([1.0e-3, 2.0e-2])
+xlabel('frequency (Hz)')
+ylabel('amplitude')
+show()

diff --git a/interfaces/python/demo_filterbank_triangle_bands.py b/interfaces/python/demo_filterbank_triangle_bands.py
new file mode 100755 (executable)
index 0000000..2e10996
--- /dev/null
+++ b/interfaces/python/demo_filterbank_triangle_bands.py
@@ -0,0 +1,47 @@
+#! /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)
+
+subplot(211)
+title('Examples of filterbank built with set_triangle_bands and set_coeffs')
+times = vstack([arange(win_s / 2 + 1) * samplerate / win_s] * n_filters)
+loglog(times.T, f.get_coeffs().T, '.-')
+xlim([50, samplerate/2])
+ylim([1.0e-6, 2.0e-2])
+ylabel('amplitude')
+
+## build a new filterbank
+
+freq_list = [60, 80, 200, 400, 800, 1200, 1600, 3200, 6400, 10000, 15000, 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)
+
+subplot(212)
+times = vstack([arange(win_s / 2 + 1) * samplerate / win_s] * n_filters)
+loglog(times.T, f.get_coeffs().T, '.-')
+xlim([50, samplerate/2])
+ylim([1.0e-6, 2.0e-2])
+xlabel('frequency (Hz)')
+ylabel('amplitude')
+
+show()