As a follow-up to T49533, I am unsatisfied with the two-part resolution:

• rETMHb658a4296885: Fix manually setting duration/offset without file.
• rESCRcc6a86d0c084: Pass length of ogg file to TimedMediaTransformOutput

The solution was for MediaWiki-extensions-Score to calculate (using TMH) and then store the length of the generated audio file, and for TimedMediaHandler to allow the value to be directly passed. As @Reedy ponders: "Wonder if this should be moved into TMH?" There was no answer specifically to that question. The parent task shows why the MIDI->audio conversion should in TMH, and not Score. This is another part of that larger issue.