Crop a video to 5:4, a frame slightly wider than square. It is the shape of 1280x1024 monitors, 8x10 inch prints, and large-format photography.
The odd monitor ratio
1280x1024 was a common LCD resolution that did not match any broadcast standard. It is 5:4 while almost everything around it was 4:3, which is why screenshots and screen recordings from that era look subtly wrong when dropped into a 4:3 timeline.
Cropping to 5:4 is the fix when that footage has to keep its original proportions rather than be stretched to fit.
Print sizes
8x10 and 16x20 inch prints are both 5:4. Video destined for a print-derived layout, a gallery wall, or a frame built for those sizes has to match, and the 7% difference against 4:3 is visible once a border is involved.
The crop and the alternative
A 1920x1080 frame cropped to 5:4 keeps 1350x1080, which is 70% of the width. Fit with bars keeps all of it instead: the full picture lands 1920x1080 in the middle of a 1920x1536 frame with 228 px of background above and below.