source: python/demos/demo_spectrogram.py @ e97d0b3

feature/autosinkfeature/cnnfeature/cnn_orgfeature/constantqfeature/crepefeature/crepe_orgfeature/pitchshiftfeature/pydocstringsfeature/timestretchfix/ffmpeg5pitchshiftsamplertimestretchyinfft+
Last change on this file since e97d0b3 was 9f8e8a9, checked in by Paul Brossier <piem@piem.org>, 12 years ago

demos/demo_spectrogram.py: add samplerate option to spectrogram

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1#! /usr/bin/env python
2
3import sys
4from aubio import pvoc, source
5from numpy import array, arange, zeros, shape, log10, vstack
6from pylab import imshow, show, cm, axis, ylabel, xlabel, xticks, yticks
7
8def 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
12
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
17
18  # analysis
19  while True:
20    samples, read = a()                              # read file
21    specgram = vstack((specgram,pv(samples).norm))   # store new norm vector
22    if read < a.hop_size: break
23
24  # plotting
25  imshow(log10(specgram.T + .001), origin = 'bottom', aspect = 'auto', cmap=cm.gray_r)
26  axis([0, len(specgram), 0, len(specgram[0])])
27  # show axes in Hz and seconds
28  time_step = hop_s / float(samplerate)
29  total_time = len(specgram) * time_step
30  print "total time: %0.2fs" % total_time,
31  print ", samplerate: %.2fkHz" % (samplerate / 1000.)
32  n_xticks = 10
33  n_yticks = 10
34
35  def get_rounded_ticks( top_pos, step, n_ticks ):
36      top_label = top_pos * step
37      # get the first label
38      ticks_first_label = top_pos * step / n_ticks
39      # round to the closest .1
40      ticks_first_label = round ( ticks_first_label * 10. ) / 10.
41      # compute all labels from the first rounded one
42      ticks_labels = [ ticks_first_label * n for n in range(n_ticks) ] + [ top_label ]
43      # get the corresponding positions
44      ticks_positions = [ ticks_labels[n] / step for n in range(n_ticks) ] + [ top_pos ]
45      # convert to string
46      ticks_labels = [  "%.1f" % x for x in ticks_labels ]
47      # return position, label tuple to use with x/yticks
48      return ticks_positions, ticks_labels
49
50  # apply to the axis
51  xticks( *get_rounded_ticks ( len(specgram), time_step, n_xticks ) )
52  yticks( *get_rounded_ticks ( len(specgram[0]), (samplerate / 2. / 1000.) / len(specgram[0]), n_yticks ) )
53  ylabel('Frequency (kHz)')
54  xlabel('Time (s)')
55
56if __name__ == '__main__':
57  if len(sys.argv) < 2:
58    print "Usage: %s <filename>" % sys.argv[0]
59  else:
60    for soundfile in sys.argv[1:]:
61      get_spectrogram(soundfile)
62      # display graph
63      show()
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