Annotation of digital music notation documents: surveying needs for a generalised implementation

The ability to annotate music notation documents offers a powerful affordance to musicologists using digital libraries, and in the organisation and discovery of annotated sources within a music digital library. In this paper we first assess the current state of the art for annotating digital scores, then report on a survey conducted into existing uses and future needs elicited from the music library community. Analysing the survey results, we distinguish between extensions which might provide generalised annotation services for music notation software, versus application-specific interfaces and visualisations using such annotation services. Drawing upon the Web Annotation Data Model, we frame this distinction in terms of annotation targets and bodies, whereby specialist or customised bodies might utilise common shared mechanisms to address targets. We demonstrate the value of the latter by, for the first time, implementing support for annotation targets in the popular and widely used Verovio open source music engraving software, adding visual indications for enumerations and ranges encoded using the MEI <annot> element, and which can be manipulated in the resultant SVG image. We conclude that common mechanisms for specifying and implementing annotation targets are not only possible, but a practical and useful foundation for music digital library tools and infrastructure.