If all you need is an audio conversion, and/or a container swap (Remux) Xmedia Recode is magical:
Copy-Video
Convert-Audio
done in moments/minutes, not hours.
If you need to change the Video Stream… Handbrake is fine, but “A Few Days Transcoding My Whole Library” is to dream the impossible dream. Change that to “A Few Months Transcoding My Whole Library” and you’ll be a little closer to what is probably the truth.
Also, any time you touch the video stream with an encoder the original quality is gone - forever. How much you can tolerate is up to you as are the settings in Handbrake you employ, but here’s a pretty solid starting point - customize as you see fit:
You could also just employ Plex’s Optimizer - if you can tolerate the way it mishandles itself - and your videos. It is pretty fast. That’s about as much of a glowing recommendation I can come up with on short notice.
Perhaps a combination of Xmedia Recode and the Plex Optimizer:
Audio Conversion/Container Swaps - Xmedia Recode for permanent changes to your file - and Plex’s Optimizer to create a ‘Compatible Version’ that you’d select at Playback time.
Note:
You have zero control over that ‘Version’. You can play it. You can’t delete the original in favor of ‘The Version’ <—and in walks some of the issues involved with Plex’s Optimizer. How much of that you can tolerate is also up to you, but as far as Options - I guess it is one.
