def _get_itd(self, max_lag):
max_lag = Sound.in_samples(max_lag, self.samplerate)
xcorr = numpy.correlate(self.data[:, 0], self.data[:, 1], 'full')
lags = numpy.arange(-max_lag, max_lag + 1)
xcorr = xcorr[self.n_samples - 1 - max_lag:self.n_samples + max_lag]
idx = numpy.argmax(xcorr)
return lags[idx]
def itd(self, duration=600e-6):
'''
Returns a binaural sound object with one channel delayed with respect to the other channel by duration (*600 microseconds*), which can be the number of samples or a length of time in seconds.
Negative dB values delay the right channel (virtual sound source moves to the left). itd requires a sound with two channels.
>>> sig = Binaural.whitenoise()
>>> _ = sig.itd(1)
>>> _ = sig.itd(-0.001)
'''
duration = Sound.in_samples(duration, self.samplerate)
new = copy.deepcopy(self) # so that we can return a new signal
if duration == 0:
return new # nothing needs to be shifted
if duration < 0: # negative itds by convention shift to the left (i.e. delay right channel)
channel = 1 # right
else:
channel = 0 # left
new.delay(duration=abs(duration), chan=channel)
return new