Nested repeats in Music Xml

[Mogens Lundholm]

Reading about music symbols I have not seen anything about more than one repeat. But may "repeats" be nested (or recursive) in Music XML?

Regards
Mogens

[Mogens Lundholm]

My user name came out wrong - tried to write MogensLundholm but musicxml appeared

[TorstenC]

I never saw a ”sheet of music” with nested repeats. Is that usual? Do musicians understand that?

[Michael Good]

I have not seen repertoire examples with nested repeat signs, but you can get similar effects with multiple segno and coda signs. The repeat attributes in the sound element (coda/tocoda, segno/dalsegno) can handle arbitrarily complex segno / coda structures. They could also be used to indicate playback for nested repeat signs too if you wished, as they indicate general backwards and forwards jumps in the music playback.

[Michael Cuthbert]

Steve Reich pieces often have nested repeats. music21 supports reading them in and figuring out if they are coherent and can expand them. They output visually perfectly through musicxml into Finale, but Finale does not play them back properly (understandable).

[Mogens Lundholm]

Could this be an algorithm for nested repeats.
1. Save the measure number of the first note
2. For all notes from start to end do
if "begin repeat" then stack position
if "end repeat" then pop the value and set position, if stack is not empty. If empty
stack then go to same relative position in measure of the first note.
Unfortunately there are melodies with no "start repeat" - but this algorithm should handle
this as the "start repeat" is in first measure.
Could this work? Is it needed?

[Michael Good]

Since nested repeats are an outlier case, I think I'd rather handle this through the existing dalsegno mechanism. MusicXML could clarify that it can be used with nested repeats. Another alternatives would be an explicit "roadmap" function for handling repeats in playback. Alternatively we could add an attribute specific to a backward repeat that can override where the repeat should jump to.

I've added this to our list of possible MusicXML features to consider for the future.

[Mogens Lundholm]

Hello

I wonder how repeats and verses should be interpreted. This may also be some kind of
"nested repeats". I think that if more verses exist (by numbering text), then the song should
be repeated. If also a repeat exists, then of cause the song will be played 2 times the number of verses (with voltas times 2,3,..),
but does Music Xml say anything (I have searched the DTD without success)

Example: Two verses and a repeat will make the song notes played four times.

What does Music Xml think?

Kind regards
Mogens

[Michael Good]

Repeat playback is controlled by different elements: the <repeat> element, the <ending> element, and many attributes of the <sound> element (dacapo, coda, tocoda, segno, dalsegno, forward-repeat, fine, divisions, and times-only).

Best practice is that repeat playback is explicitly encoded with these elements, not left up to inference from the presence of lyrics. This won't always happen though since many people have used notation programs just to make things look right, not to play correctly. If playback is not setup correctly in a program like Finale or Sibelius, playback is not going to export correctly to the MusicXML file either.