[FFmpeg-user] "Four up" output?

[Carl Zwanzig]

On 6/27/2020 8:53 AM, Simon Roberts wrote:
> 1) create a composite output that has all four of the inputs laid out one
> per quadrant, so all can be seen on a single display

Google "ffmpeg multiviewer", you'll find a handful of ideas, including this-
https://trac.ffmpeg.org/wiki/Create%20a%20mosaic%20out%20of%20several%20input%20videos

That should get you started.

z!