User:Dispenser has collected a list of cases where video rendering fails: https://commons.wikimedia.org/w/index.php?title=User:Dispenser/sandbox&oldid=93443761
Bug 43331 also kicks in with https://commons.wikimedia.org/wiki/File:2012_State_Of_The_Union_Address_%28720p%29.ogv
"Added to Job queue 68 days, 21 hours, 38 minutes, 20 seconds ago" (!)
There appear to actually be multiple different errors, depending on whether the file is being transcoded to WebM or Ogg.
Version: master
Severity: normal