‘Crop to Fill’ is still done in an abysmal manner. Take a 1920x800, 16:9 source (and movie I had once cropped myself). Now, the proper way to get rid of the letterbox, is to FIRST crop, as follows (in VapourSynth syntax):
vid = core.std.CropRel (clip=vid, left=248, right=248, top=0, bottom=0)
(248 = 140 x 1.77) Then, and only then, do you ‘stretch’ (upscale) to 2160p. What TVAI apparently does, however, is first upscale the frame x1.35 (to reach 1080p, from 800p), and then you wind up effectively upscaling a 2592x1080 image to 4k (that is then cropped to the sides later).
The result is a dismal drop in fps (like to 2.5fps on my RTX 4090), a slowdown consistent with the totally unnecessary pre-upscaling.
