How to reconstruct audio signal from the spectrogram (output of assemble_coeffs)

[binarygo]

Hello

Thanks a lot for the nice package! I am looking for a "lossless way" to convert audio signal to spectrogram (in mel scale) and back to audio signal again. This seems to be a great solution.

However, after calling the assemble_coeffs() to construct spectrogram from CQT slices. How do I transform the spectrogram back to CQT slices (and thus backward() to audio signal again)? The overlap-add operation in the assemble_coeffs() seems to be irreversible.

Sorry for the dumb question, but it will be great if you could help on this. Thanks!

[jeremydeanw]

Hey Binarygo, did you ever figure out how to do this?

[grrrr]

Hi all, not sure whether i understand it right. Have you had a look at examples/transform_stream.py ?
It seems it does what you want to achieve - only the frequency scale needs to be modified.

[jeremydeanw]

Hi, dont mean to jack the thread. But to convert an audio file to a spectrogram, am I doing "python spectrogram.py myaudio.wav --output image.npz" ? And for the reconstruction I am to use transform_stream.py? Also how do I get an image out of the npz once it's created?