STFT and ISTFT in Python

Question

Is there any form of short-time Fourier transform with corresponding inverse transform built into SciPy or NumPy or whatever?

There's the pyplot specgram function in matplotlib, which calls ax.specgram(), which calls mlab.specgram(), which calls _spectral_helper():

#The checks for if y is x are so that we can use the same function to
#implement the core of psd(), csd(), and spectrogram() without doing
#extra calculations.  We return the unaveraged Pxy, freqs, and t.

but

This is a helper function that implements the commonality between the 204 #psd, csd, and spectrogram. It is NOT meant to be used outside of mlab

I'm not sure if this can be used to do an STFT and ISTFT, though. Is there anything else, or should I translate something like this?

Answer 1

I would definitely recommend using _spectral_helper() or copying the parts that you want from _spectral_helper() to form your own functions. To do the ISTFT I think that you just need to replace

fy = np.fft.fft(thisY, n=pad_to)

with

fy = np.fft.ifft(thisY, n=pad_to)

Answer 2

I also found this on GitHub, but it seems to operate on pipelines instead of normal arrays:

http://github.com/ronw/frontend/blob/master/basic.py#LID281

Answer 3

Found another STFT, but no corresponding inverse function:

http://code.google.com/p/pytfd/source/browse/trunk/pytfd/stft.py