ref: dea34a1fa660219ac8f27471ec65da0bb16c8b72
dir: /interfaces/python/demo_spectrogram.py/
#! /usr/bin/python
import sys
from aubio import pvoc, source
from numpy import array, arange, zeros, shape, log10, vstack
from pylab import imshow, show, cm, axis, ylabel, xlabel, xticks, yticks
def get_spectrogram(filename):
samplerate = 44100
win_s = 512 # fft window size
hop_s = win_s / 2 # hop size
fft_s = win_s / 2 + 1 # spectrum bins
a = source(filename, samplerate, hop_s) # source file
pv = pvoc(win_s, hop_s) # phase vocoder
specgram = zeros([0, fft_s], dtype='float32') # numpy array to store spectrogram
# analysis
while True:
samples, read = a() # read file
specgram = vstack((specgram,pv(samples).norm)) # store new norm vector
if read < a.hop_size: break
# plotting
imshow(log10(specgram.T), origin = 'bottom', aspect = 'auto', cmap=cm.gray_r)
axis([0, len(specgram), 0, len(specgram[0])])
ylabel('Frequency (Hz)')
xlabel('Time (s)')
# show axes in Hz and seconds
time_step = hop_s / float(samplerate)
total_time = len(specgram) * time_step
ticks = 10
xticks( arange(ticks) / float(ticks) * len(specgram),
[x * total_time / float(ticks) for x in range(ticks) ] )
yticks( arange(ticks) / float(ticks) * len(specgram[0]),
[x * samplerate / 2. / float(ticks) for x in range(ticks) ] )
if __name__ == '__main__':
if len(sys.argv) < 2:
print "Usage: %s <filename>" % sys.argv[0]
else:
for soundfile in sys.argv[1:]:
get_spectrogram(soundfile)
# display graph
show()