[raymond_goo]

Is it also possible to undo a stack video ?

[iso1631]

Assuming a 3840x2160 2x2 input

Top left: ffmpeg -i input.mov -vf "crop=1920:1080:0:0" out-tl.mp4

Top right: ffmpeg -i input.mov -vf "crop=1920:1080:1920:0" out-tr.mp4

Bottom left: ffmpeg -i input.mov -vf "crop=1920:1080:0:1080" out-bl.mp4

Bottom right: ffmpeg -i input.mov -vf "crop=1920:1080:1920:1080" out-br.mp4

Details at

https://www.ffmpeg.org/ffmpeg-filters.html#crop

[ponderingfish]

Cropping is the only way I can think of, because, it merges the 4 videos (or how many ever in the stack) into a new video frame.

[evan_]

Like, crop the video? Yes