BUMP!
I'm getting "unable to parse uploaded file" for roughly 250-270MB webm and mp4 files. File upload was not broken previously. I think what's happening is webmaster made an update to [or just flat out created] a client-side script which validates the files on the client so as to reduce server load. Problem is webmaster's cute little script is in JavaShit, which means 16x the RAM, 64x the processor cycles, of a normal written-in-C routine. This script attempts to parse the oversized files, and on my Chinkpad X200 either it's not parsing fast enough (so the server rejects the post for timeout) or the script is crashing/failing in the background.
Upload of large files worked previously, but doesn't work now which leads me to the worrying conclusion that webmaster does not unit test his changes. EndChan could be sitting on similar bugs and quality of code that Infinity had, leading to the 8chan IP leaks.
Anyway, I'm going to try and cripple that routine client-side here and see if that doesn't fix it. If it does, I'll publicly release the code so people can post big files (and hopefully ones off the allow list, if it's this script doing the validation and not the server, to teach webmaster a lesson about coding and design laziness).