Renaming audio/video files leaves orphaned transcode table entries -- for instance commons has several failed/queued transcodes for "CutterPlotting.ogg" which was renamed to "CutterPlotting.ogv". A bunch of these entries are visible on https://commons.wikimedia.org/wiki/Special:TimedMediaHandler as "queued" even though they can never succeed.
Currently requeueTranscodes.php can't fix these entries because it always fetches first from the image table, and there's no image table entry for the old name.