[HELP] how to crop 720×480 to 1920×1080 without stretch?

[ssdde]

to keep original ratio, if i set 1920, it will set height to 1280 automaticly,




if i uncheck "Auto ajust", set 1920×1080 manually, the encoded picture is stretched, so how to crop 720×480 to 1920×1080 without stretch?

and what's the mod value for in the Auto ajust?

i using Vapoursynth , nnedi3 16×6 spline64, thanks.