A beat histogram is formed using a perceptual onset detection frontend, then leaky integrators for each of 100 periodicities. On the ensuing histogram, statistics are taken.
Operate feature extraction at control rate
Output of FFT UGen
 entropy of beat histogram
 ratio of the largest to the second largest entries in the beat histogram
 diversity (Simpson's D measure) of beat histogram
 metricity (consistency of high energy histogram entries to integer multiples or divisors of strongest entry)