Notational representation vs. musical performance

MusicXML is a music notation file format, that is, it deals especially with the layout of music notation and the correct graphical representation, that is, how a piece of music should look.

However, MusicXML music data also contains elements that define how a piece of music should sound. For example, these are used when creating a MIDI file from MusicXML. This means that MusicXML has things in common with MIDI.

MIDI is a music interchange format for performance applications like Cubase or other sequencers. The MIDI file format is designed for playback. The main focus of the MIDI file format lies in the performance, not in the notation.