logfbank missing energy

[bhigy]

Hi there,

I was wondering if there is a reason why the output of fbank and logfbank functions don't return both the energy. I usually use logfbank features with energy, which obliges me to redefine logfbank while it would be very easy to return the energy as well.

Thanks,
Bertrand

[shuttle1987]

As you can see here:

python_speech_features/python_speech_features/base.py

Lines 66 to 84 in 044d307

	def logfbank(signal,samplerate=16000,winlen=0.025,winstep=0.01,
	nfilt=26,nfft=512,lowfreq=0,highfreq=None,preemph=0.97,
	winfunc=lambda x:numpy.ones((x,))):
	"""Compute log Mel-filterbank energy features from an audio signal.
	:param signal: the audio signal from which to compute features. Should be an N*1 array
	:param samplerate: the samplerate of the signal we are working with.
	:param winlen: the length of the analysis window in seconds. Default is 0.025s (25 milliseconds)
	:param winstep: the step between successive windows in seconds. Default is 0.01s (10 milliseconds)
	:param nfilt: the number of filters in the filterbank, default 26.
	:param nfft: the FFT size. Default is 512.
	:param lowfreq: lowest band edge of mel filters. In Hz, default is 0.
	:param highfreq: highest band edge of mel filters. In Hz, default is samplerate/2
	:param preemph: apply preemphasis filter with preemph as coefficient. 0 is no filter. Default is 0.97.
	:param winfunc: the analysis window to apply to each frame. By default no window is applied. You can use numpy window functions here e.g. winfunc=numpy.hamming
	:returns: A numpy array of size (NUMFRAMES by nfilt) containing features. Each row holds 1 feature vector.
	"""
	feat,energy = fbank(signal,samplerate,winlen,winstep,nfilt,nfft,lowfreq,highfreq,preemph,winfunc)
	return numpy.log(feat)

The function just calls fbank so perhaps a workaround is just to call fbank directly yourself and use numpy.log on the result ?

[bhigy]

Sure, that's actually how I solved the problem. But I think it wouldn't harm and would be more consistent to return it in both cases.