Sadly, my current server is an old all-in-one, so adding a GPU will be difficult. My plan is to make due for now until I can get some proper hardware.
The current plan is - rather than bringing the hardware up to spec - I'll try bringing the spec down to the hardware, by pre-encoding everything to something like H264. (While keeping originals, since I have the space.)
Thank you for the response and the resource, though! I'll definitely check it out!