Unfortunately I can’t control format of content. We have quite a lot that will only ever be available at DVD resolution.
My TV supports 4:3 aspect and will add horizontal letterboxing as appropriate to maintain aspect ratio.
My choice is pass-thru native resolution and let the TV deal with/upscale with excellent results or leave amlogic do it with noticeably reduced quality.
All works great for the most part 
except for this bug 