4 from aubio import pvoc, source
5 from numpy import array, arange, zeros, log10, vstack
6 import matplotlib.pyplot as plt
8 def get_spectrogram(filename, samplerate = 0):
9 win_s = 512 # fft window size
10 hop_s = win_s / 2 # hop size
11 fft_s = win_s / 2 + 1 # spectrum bins
13 a = source(filename, samplerate, hop_s) # source file
14 if samplerate == 0: samplerate = a.samplerate
15 pv = pvoc(win_s, hop_s) # phase vocoder
16 specgram = zeros([0, fft_s], dtype='float32') # numpy array to store spectrogram
20 samples, read = a() # read file
21 specgram = vstack((specgram,pv(samples).norm)) # store new norm vector
22 if read < a.hop_size: break
25 fig = plt.imshow(log10(specgram.T + .001), origin = 'bottom', aspect = 'auto', cmap=plt.cm.gray_r)
27 ax.axis([0, len(specgram), 0, len(specgram[0])])
28 # show axes in Hz and seconds
29 time_step = hop_s / float(samplerate)
30 total_time = len(specgram) * time_step
31 print "total time: %0.2fs" % total_time,
32 print ", samplerate: %.2fkHz" % (samplerate / 1000.)
36 def get_rounded_ticks( top_pos, step, n_ticks ):
37 top_label = top_pos * step
39 ticks_first_label = top_pos * step / n_ticks
40 # round to the closest .1
41 ticks_first_label = round ( ticks_first_label * 10. ) / 10.
42 # compute all labels from the first rounded one
43 ticks_labels = [ ticks_first_label * n for n in range(n_ticks) ] + [ top_label ]
44 # get the corresponding positions
45 ticks_positions = [ ticks_labels[n] / step for n in range(n_ticks) ] + [ top_pos ]
47 ticks_labels = [ "%.1f" % x for x in ticks_labels ]
48 # return position, label tuple to use with x/yticks
49 return ticks_positions, ticks_labels
52 x_ticks, x_labels = get_rounded_ticks ( len(specgram), time_step, n_xticks )
53 y_ticks, y_labels = get_rounded_ticks ( len(specgram[0]), (samplerate / 1000. / 2.) / len(specgram[0]), n_yticks )
54 ax.set_xticks( x_ticks )
55 ax.set_yticks ( y_ticks )
56 ax.set_xticklabels( x_labels )
57 ax.set_yticklabels ( y_labels )
58 ax.set_ylabel('Frequency (kHz)')
59 ax.set_xlabel('Time (s)')
60 ax.set_title(os.path.basename(filename))
61 for item in ([ax.title, ax.xaxis.label, ax.yaxis.label] +
62 ax.get_xticklabels() + ax.get_yticklabels()):
63 item.set_fontsize('x-small')
66 if __name__ == '__main__':
68 print "Usage: %s <filename>" % sys.argv[0]
70 for soundfile in sys.argv[1:]:
71 fig = get_spectrogram(soundfile)
74 #outimage = os.path.basename(soundfile) + '.png'
75 #print ("writing: " + outimage)
76 #plt.savefig(outimage)