ref: 9a226ef2ea65603356ec86c0ef42dca95cea8782
dir: /python/demos/demo_onset_sinusoid.py/
#! /usr/bin/env python
from numpy import random, sin, arange, ones, zeros
from math import pi
from aubio import fvec, onset
def build_sinusoid(length, freqs, samplerate):
return sin( 2. * pi * arange(length) * freqs / samplerate)
def run_onset(p, input_vec):
f = fvec (p.hop_size)
cands = []
count = 0
for vec_slice in input_vec.reshape((-1, p.hop_size)):
f[:] = vec_slice
cands.append(o(f))
return cands
methods = ['default',
'energy',
'complex',
'phase',
'specdiff',
'kl',
'mkl',
'specflux',
'centroid',
'spread',
'skewness',
'kurtosis',
'slope',
'decrease',
'rolloff',
]
cands = {}
buf_size = 2048
hop_size = 512
samplerate = 44100
sin_length = (samplerate * 10) % 512 * 512
freqs = zeros(sin_length)
partition = sin_length / 8
pointer = 0
pointer += partition
freqs[pointer: pointer + partition] = 440
pointer += partition
pointer += partition
freqs[ pointer : pointer + partition ] = 740
pointer += partition
freqs[ pointer : pointer + partition ] = 1480
pointer += partition
pointer += partition
freqs[ pointer : pointer + partition ] = 400 + 5 * random.random(sin_length/8)
a = build_sinusoid(sin_length, freqs, samplerate)
for method in methods:
o = onset(method, buf_size, hop_size, samplerate)
cands[method] = run_onset(o, a)
print "done computing"
if 1:
from pylab import plot, show, xlabel, ylabel, legend, ylim, subplot
subplot (211)
legend(methods+['ground truth'], 'upper right')
xlabel('time (s)')
ylabel('amplitude')
ramp = arange(0, sin_length).astype('float') / samplerate
plot(ramp, a, ':')
subplot (212)
ramp = arange(0, sin_length / hop_size).astype('float') * hop_size / samplerate
for method in methods:
plot(ramp, cands[method],'.-')
legend(methods, 'upper right')
xlabel('time (s)')
ylabel('spectral descriptor value')
show()