The Parsons Code for Melodic Contours

Each pair of consecutive notes is coded as "U" ("up") if the second note is higher than the first note, "R" ("repeat") if the pitches are equal, and "D" ("down") otherwise. Rhythm is completely ignored. Thus, the first theme from Beethoven's 8th symphony that is shown above would be coded DUUDDDURDRUUUU. Note that the first note of any tune is used only as a reference point and does not show up explicitly in the Parsons code. You can enter an asterisk (*) in the Parsons code field for the first note.

In his "Directory of Classical Themes" (Spencer Brown, 1975), D. Parsons showed that this simple encoding of tunes, which ignores most of the information in the musical signal, can still provide enough information for distinguishing between a large number of tunes.