1920x1080

[Daffy]

Correct, you should render a small segment to see if that solves it.

[Bixel]

i play my Vice City at 1920x1080 but its streched and tommy looks like fat fuck

[A maid]

[Rainbow]

Problem is fully gone indeed. But Uploading a .mkv to youtube wont work for some reason. It is a accepted file container on YT but for some reason it cant be processed  Someone knows a solution?

Read something about converting it to a .MP4.. but how will this affect my quality and other stuff like that? and if not, how can I do this in a good way?