RIFE only works for 32-px aligned frame size, so we have two options (for example for 1920*1080 frame):
1. add 8px height black line, interpolate, cut away 8px line
2. cut 24px line --> interpolate 1920*1056 frame
SVP now does (1) for frame height <= 2560 and (2) for >2560.
If you want always do (1) then for now you can edit SVP 4\script\generate.js, line 458, change it to:
var pad_up = pad;