Automated extraction of motivic patterns and application to the analysis of Debussy’s Syrinx

The basic principle of motivic pattern extraction consists of detecting repeated motives, i.e. identifying several short extracts or subsequences as instances, or occurrences, of a same series of description called pattern. The approach is focused here on monodic sequences: music is considered as a series of notes without superpositions. Patterns are formalised as chains of states – called pattern chains. As patterns can accept multiple alternative continuations, patterns chains can be extended by multiple branches. Hence, patterns are aggregated into one single tree, called pattern tree, and each pattern chain is as a branch of the tree. Similarly, each pattern occurrence can accept multiple alternative continuations. Hence, the set of all pattern occurrences that are initiated by one note forms a tree, called pattern occurrence tree. 1.2. Musical dimensions Patterns are detected along multiple musical dimensions, are indicated below. See (Lartillot and Toiviainen, in press), for a detailed explanation of the dimensions.