Symbolic Music Representation in the MUSITECH Project Tillman Weyde Research Department of Music and Media Technology University of Osnabrück Germany tweyde@uos.de Abstract The inclusion of Symbolic Music Representation into the MPEG standard and the definition and selection of an appropriate technology are currently worked on in the MPEG Ad-Hoc-Group on Symbolic Music Representation. In this context, the work of the MUSITECH project may be of interest. In MUSITECH an integrated representation of mu- sical information, including score, performance, audio, metadata, and music collections has been developed. The development has shown that a decomposition of musical knowledge is necessary to maximize expressiveness, usefulness, and flexibility of such a representation. Based on this representation, an infrastructure for interactive applications in music consist- ing of a framework, a component model, and standard components are being developed. Some results are presented in this paper. 1 Introduction Symbolic music representation as it has been discussed in the MPEG-AHG is an important part of musical information. It complements audio and metadata, enabling applications with added value. To maximize the usefulness of a representation, the necessary structures have to be explored with respect to effectiveness, semantic clarity, completeness (for a defined scope), and extensibility. In the MUSITECH project, an object model of musical information has been devel- oped, which concentrates on symbolic information on performance, scores and musical structure. It has been implemented in Java and supports storage in XML files and in databases. Based on the object model an application framework and component model have been implemented, used, and examined for several aspects of symbolic music representation. 2 Object Model The basic idea of the MUSITECH object model is to decompose musical information and iso- late largely independent layers. Based on these informational building blocks, complex musical structures can be reconstructed with great flexibility for different purposes. The independence of the layers enables the integrated representation of a wide variety of musical information, like audio, performance information, metric, harmonic and structural interpretations, comments and external links. Layers of Information The musical information in MUSITECH is represented on several layers covering different aspects of music. The layers are defined by degrees of abstraction (audio, performance, notation), by aggregation (piece, collection), and by the kinds of structures represented (meter, harmony). The least abstract form of representation is audio data, which are represented as clips with a specified onset time and duration. The actual audio data can be retrieved from files or streaming sources. 1