This paper presents an overview on a future IEEE standard aimed at providing an overall description of music. This format, known as IEEE PARI 599, is based on the XML meta-language. Its purpose is taking into account the heterogeneous multimedia representations of music, such as audio tracks, video clips and graphical instances of score. The key characteristics of the format are the possibility to enjoy such heterogeneous contents in a synchronized way and the possibility to switch from a particular representation to another in real-time. After a short description of the particular XML language we have adopted, a case study will be presented: an application installed at the exhibition "Celeste Aida" held at Teatro alia Scala in November 2006 - January 2007.