We're in progress of deploying a small change to the video scalers[1], which should improve availability of newly uploaded video and audio files.
The queue will now be split in two, one which covers low-resolution conversions for relatively short files, and one which covers long files and high-resolution conversions. When there's a flood of large uploads, other new files should still go through the high-priority queue while the large uploads and HD conversions may back up on the low-priority queue.
The queue-runner side is updated now (done during the 'puppet SWAT' deployment window), with the MediaWiki side ready to roll around 19:00 UTC (11am Pacific time, regular SWAT deployment window).
[1] https://gerrit.wikimedia.org/r/#/c/336846/
-- brion