Understand algorithm for AudioLocalMeasurements, & ModifiedKullbackLeibler?

GROUPS:
 Matthew Sottile 1 Vote I recently was doing some experiments with AudioLocalMeasurements for some music analysis tasks, and in the process of trying to explain what I did to someone I realized that I didn't know what the ModifiedKullbackLeibler measurement is computing. Specifically, what is modified versus regular KL divergence, and what is done to the frequency spectra of the windows being compared? Without understanding what the algorithm is actually reporting, it's hard to make any interpretation of the results that it computes.
 Carlo Giacometti 1 Vote The implementation is from Brossier, P. M. (2006). Automatic annotation of musical audio for interactive applications (Doctoral dissertation), which itself is a variation of the one presented in Hainsworth, S. W., & Macleod, M. D. (2003, September). Onset Detection in Musical Audio Signals. In ICMC.The formula is:  d[k] = Log[1 + X[k]/(X[k - 1] + epsilon)]  where X[k] is the kth frame of the magnitude spectrogram. The result is then standardized (using Standardize[res,Mean,Max]).