The MusicXML element <duration>
While it at first seems that the MusicXML documentation clearly defines the MusicXML element <duration>, the larger context of its use is not so well defined. As a result, different implementers of MusicXML have adopted different interpretations of this element, and have developed different overall protocols from that. The result is that the interchange of scores between different notation programs via MusicXML does not, in this area, go well.
Attached in Issue 5 of my Technical Paper "MusicXML—the duration element" (it was previously styled "Technical Report"), in which I discuss an extensive analysis of this mysterious topic I have conducted. It is lengthy and detailed, for which I make no apology. The topic itself is very complex and confusing, and I did not cause that.
I would be glad to answer any questions on this paper, or this matter.