A Python implementation of the YIN Pitch Detection Algorithm as described by Alain de Cheveigne and Igor Stravinsky in this paper:
YIN, a fundamental frequency estimator for speech and music http://audition.ens.fr/adc/pdf/2002_JASA_YIN.pdf
This implementation works with WAV files and includes some neat preprocessing functions to condition the signal and improve performance. Step 6 has not been implemented yet.