I've looked at MusicXML as an intermediary format to convert to from MIDI but found it to be overly complex and ended up just using the MIDI data in JSON form directly. This worked well except of course for the fact that MIDI is quite lossy (rests aren't in there, slurs are implicit, there are no 'beat' markers and so on).<p>Music formats are tricky, some are more suitable for performance, some more for archival storage or composition. It's enough to drive you bonkers at times, especially if you want exact representation and slowly you realize you are just not going to get it perfect no matter how hard you try.
Gah. Data translation, between almost matching schemas (ontologies), has been 1/2 of my professional career. Probably.<p>I don't know if this applies: S-notation for turntablism (DJing) represents pitch. But I couldn't quickly find any XML schemas for S-notation.