The MusicXML format supports six levels of beaming, up to 256th notes. Unlike the number-level attribute, the beam-level attribute identifies concurrent beams in a beam group. It does not distinguish overlapping beams such as grace notes within regular notes, or beams used in different voices.
<xs:simpleType name="beam-level"><xs:annotation><xs:documentation>The MusicXML format supports six levels of beaming, up to 256th notes. Unlike the number-level attribute, the beam-level attribute identifies concurrent beams in a beam group. It does not distinguish overlapping beams such as grace notes within regular notes, or beams used in different voices.</xs:documentation></xs:annotation><xs:restriction base="xs:positiveInteger"><xs:minInclusive value="1"/><xs:maxInclusive value="6"/></xs:restriction></xs:simpleType>