[FFmpeg-user] Crop 4K Video into Four 1080p Videos?

[Gyan]

On Mon, Jun 26, 2017 at 11:58 PM, Clay D. Montgomery <clay at montgomery1.com>
wrote:

> Hello,
>
>     I'm wondering if it is possible to use ffmpeg to slice 4K video into a
> set of four 1080p videos and do it without scaling.
>

You need to use the crop filter. For four distinct outputs,

    ffmpeg -i input -vf crop=1920:1080:0:0 output1 -vf
crop=1920:1080:1920:0 output2 -vf crop=1920:1080:0:1080 output3 -vf
crop=1920:1080:1920:1080 output4

(I've ignored audio. The above command will transcode it. Add -c:a copy
before each output to avoid that)