I've been trying to render a video in 21:9 aspect ratio, specifically 2560 x 1080. I modified a Sony AVC/MVC template I was using to render in 1080p to render in 21:9, but every time I try to render, I get "An invalid argument was specified". I also tried using MainConcept AVC/AAC and got "The reason for the error could not be determined".
I'm using Movie Studio Platinum 13.0 - Steam Powered.