Question about MusicXML Export <duration> tag

Hi,

I was playing around with exporting MusicXML files in Musescore as I am building a node module to convert MusicXML to JSON - https://github.com/jgab3103/musicXML2MusicJSON

I noticed the tags don't seem to a standard that undepins them. So when I exported a bach piece the duration tag equates a quarter note to 4, the chopin piece equated the quarter note was 256 and mahler piece equated to quarter note to 480. Example of what I mean is below.

Can anyone point me to docs as to how MuseScore calculates duration tag when it exports to MusicXML?

Hope this is the right place to ask this! first time I have posted to the forum....

example....
Mahler symph exported from Musescore to MusicXML

D
5

960
1
half
natural
down

Chopin nocturne exported from Musescore to MusicXML

F
5

240
1
eighth
down
1
continue

Bach invention exported from Musescore to MusicXML

C
5

4
1
eighth
down
1
end

Jamie

biodigitaljazz.org
stelupa.com