Apply blur to a region of the video
video filters
// shell
$ ffmpeg -i input.mp4 -vf "split[original][copy];[copy]crop=200:200:100:100,boxblur=10[blurred];[original][blurred]overlay=100:100" output.mp4$ ffmpeg -i input.mp4 -vf "split[original][copy];[copy]crop=200:200:100:100,boxblur=10[blurred];[original][blurred]overlay=100:100" output.mp4