Onset detection

onset_detect([y, sr, onset_envelope, …])	Basic onset detector.
onset_backtrack(events, energy)	Backtrack detected onset events to the nearest preceding local minimum of an energy function.
onset_strength([y, sr, S, lag, max_size, …])	Compute a spectral flux onset strength envelope.
onset_strength_multi([y, sr, S, lag, …])	Compute a spectral flux onset strength envelope across multiple channels.