The part-list identifies the different musical parts in this document. Each part has an ID that is used later within the musical data. Since parts may be encoded separately and combined later, identification elements are present at both the score and score-part levels. There must be at least one score-part, combined as desired with part-group elements that indicate braces and brackets. Parts are ordered from top to bottom in a score based on the order in which they appear in the part-list.
The
<part-list>element.The part-list identifies the different musical parts in this document. Each part has an ID that is used later within the musical data. Since parts may be encoded separately and combined later, identification elements are present at both the score and score-part levels. There must be at least one score-part, combined as desired with part-group elements that indicate braces and brackets. Parts are ordered from top to bottom in a score based on the order in which they appear in the part-list.
See
https://www.w3.org/2021/06/musicxml40/musicxml-reference/elements/part-list/