Duration is a positive number specified in division units. This is the intended duration vs. notated duration (for instance, differences in dotted notes in Baroque-era music). Differences in duration specific to an interpretation or performance should be represented using the note element's attack and release attributes.
The duration element moves the musical position when used in backup elements, forward elements, and note elements that do not contain a chord child element.
The
<duration>element.Duration is a positive number specified in division units. This is the intended duration vs. notated duration (for instance, differences in dotted notes in Baroque-era music). Differences in duration specific to an interpretation or performance should be represented using the note element's attack and release attributes.
The duration element moves the musical position when used in backup elements, forward elements, and note elements that do not contain a chord child element.
See
https://www.w3.org/2021/06/musicxml40/musicxml-reference/elements/duration/