Various overlap-add (OLA), synchronized overlap-add (SOLA), waveform similarity overlap-add (WSOLA), and phase vocoder algorithms
Purely educational and should not be used for anything ...
Requires librosa, numpy, and IPython, optionally matplotlib for displaying spectrograms

Jupyter Notebook organization:

• OLA
  • direct pitch shift
    • OLA
    • SOLA
  • time scale, playback rate change
    • OLA
    • SOLA
    • WSOLA
• Phase vocoder
  • ignore transients
    • direct pitch shift
    • scale hop length
    • time scale, playback rate change
  • add transients back in
    • direct pitch shift
    • scale hop length
    • time scale, playback rate change