reconstructing time-stretched signals for filtering purposes I would like to know if it's possible to reconstruct the original time domain signal from it's time-stretched version? Is there any algorithm out there that can do this? Python, Matlab, etc?

I want to isolate certain sound events in the signal, however, the events are really close together, that it's hard to filter. A solution that I had in mind was to stretch the signal, filter this time-stretched signal and then reconstruct back by back stretching using inverse stretching factor to get the original length.

The algorithm will of course have to keep the correct pitch at all times. Is this possible or not?
Keeping your “correct pitch” after a time stretch can become a more difficult problem than your original problem of filtering short events.  Both require a time-frequency resolution trade-off.