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Fractional Numerators in Time Signatures in 3.0

Moderator: Michael Good

Fractional Numerators in Time Signatures in 3.0

Postby Evan Brooks » Sat Oct 04, 2014 2:42 am

Back in 2002, Michael Good posted that:

MusicXML can handle fractional time signatures. To use the example
of three-and-two-thirds quarter time:

<time>
<beats>3</beats>
<beat-type>4</beat-type>
<beats>2/3</beats>
<beat-type>4</beat-type>
</time>

(See: https://www.mail-archive.com/[email protected] ... 02186.html)

My understanding is that such a construct in MusicXML would be printed in the score as the sum of two fractions - 3 over 4, and then two-thirds over 4. In fact, any groups of multiple beats/beat-type pairs would be printed as the sums of all the pairs, with each pair written as its own fraction.

I think the original post was trying to represent the fraction whose numerator is 4 2/3, and whose singular denominator is 4.

Currently, if we want to represent a complex numerator, such as "2+3+2", we would use the string "2+3+2" as the actual text in the <beats> element. Since there is no ASCII character for "1/2", etc, there is no great way to represent that in the <beats> element text. It could be done by specifying Unicode in the element text instead, but I'm not sure how to do that in a standard way.

First, is my interpretation of the 2002 post incorrect? If so, how? If not, and given the benefit of 12 years since the original post, how would you recommend that fractional numbers be represented within a single numerator's text string?

A second, but related question, is what characters EXACTLY are permitted in both the numerator string (<beats> element), and the denominator string (<beat-type> element)?

If we are to handle all possible characters here, it will certainly require multiple fonts to be able to display the potential musical, text or other characters that one could legally find there. Perhaps these two elements would be good places to actually define the allowable characters in the string, so that creators of MusicXML documents have some guidance, and application writers can deal with a reasonable set of symbols to render. I know that many places in the MusicXML spec will restrict strings to a finite set of values, however I am suggesting here that the characters used in these strings be restricted to a finite set of characters, rather than putting any limit on how they are then composed.
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Re: Fractional Numerators in Time Signatures in 3.0

Postby Michael Good » Tue Oct 07, 2014 5:12 pm

Hi Evan,

I would probably recommend using <beats>3⅔</beats> or, less desirably, <beats>3 2/3</beats> in this situation. I don't believe this is supported in most current notation programs. We have not heard much demand for it in the past 12 years.

This is something that would be good to clarify in future versions of MusicXML, especially in conjunction with SMuFL support. SMuFL has entries for ¼, ½, ¾, ⅓, and ⅔ in its time signature block, but not for the other vulgar fractions in the Unicode Number Forms block.
Michael Good
VP of MusicXML Technologies
MakeMusic, Inc.
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