This is Paulstretch , Python version by Nasca Octavian PAUL, Targu Mures, Romania http://www.paulnasca.com/ Requirements: Numpy, Scipy Original version with GUI: http://hypermammut.sourceforge.net/paulstretch/ For start, I recomand to use "paulstretch_stereo.py". The "paulstretch_mono.py" is a very simple test implementation of the Paulstretch algorithm. The "paulstretch_newmethod.py" is a extended/slower Paulstretch algorithm which has onset detection. "paulstretch_steps.png" describes the steps of Paulstretch algorithm graphically. The Paulstretch algorithm is released under Public Domain.