Measures can contain more notes
than the time signature says. Some applications use this approach
for ‘frenched’ scores, i.e., for staves that are present but hidden
and not printed.
While doing so is valid MusicXML, having measures with lengths that
differ from their designated time signatures is semantically invalid.
A better approach is to actually use time signatures, setting their
‘print-object’ property to ‘no’.
Here, the first and third measure contain five quarters instead of
four.MusicXML Part1G2D411quarterE411quarterF411quarterG411quarterA411quarterA411quarterA411quarterA411quarterA411quarterD411quarterE411quarterF411quarterG411quarterA411quarterA411quarterA411quarterA411quarterA411quarter