Abstract

Composition is viewed as a process that has its own temporal dimension. This process can sometimes be highly non-linear, sometimes is carried out in realtime during a performance. A model is proposed that unifies the creational and the performance time and that traces the history of the creation of a piece. This model is based on a transformation that enhances data structures to become persistent. Confluent persistence allows navigation to any previous version of a piece, to create version branches at any point, and to combine different versions with each other. This concept is tuned to integrate two important aspects, retroactivity and multiplicities. Three representative problems are posed: How to define dependancies on entities that change over time, how to introduce changes ex-post that affect future versions, and how to continue working on parallel versions of a piece. Solutions based on our test implementation in the Scala language are presented. Our approach opens new possibilities in the area of music analysis and can conflate disparate notions of composition such as tape composition, interactive sound installation, and live improvisation. They can be represented by the same data structure and both offline and realtime manipulations happen within the same transactional model.

Citations