Grammar Induction for Musical Melodies

Universiy of Southern California, Spring 2007

in ISE575/EE675/CSCI575/PSYCH675

by Reid Swanson (2007)

Output

Here are a few example parses from Bach's Well Tempered Clavier Fugue 1 (BWV 846) that are output by my system. The parser was trained on all 48 Bach Fugues and was run on the first (lowest) voice of the piece. The numbers correspond to the relative pitch values, where 0 is the first pitch in the segment. All other pitches are offset from 0. Full pitch steps are in increments of 2, while half steps (sharps and flats) are in increments of 1. A first glance at the output might suggest that there are more terminal nodes in my tree than in the score. This is a consequence of the kern data file format in which null tokens and rests are transcribed even though a formal notation is not present in the score. 100 and 200 are special markers in my output notation that represent these tokens. 100 means that a note was played in another voice but not in the current one. 200 means that a rest was inserted instead of an actual note. Unfortunately the terminals don't always line up with the corresponding notes but I have done my best to at least line up the first and last note in the phrase. Additionally if you roll your mouse over the images I have highlighted various clusters at a granularity that looked meaningful to me.