Sometimes you may need to remove fisheye effect from your videos. Correcting distortion will give almost the same results as shooting with a wide-angle non-fisheye lens.
Use ffmpeg with a built-in filter lenscorrection.
ffmpeg -i <input_file> -map_metadata 0 -c:a copy -c:v h264 -crf 22 -vf "lenscorrection=cx=0.5:cy=0.5:k1=-0.227:k2=-0.022" <output_file>
Keys are:
-i— specify input file-map_metadata 0— save all meta tags-c:a copy -c:v h264 -crf 22— set codecs for audio and video-vf "lenscorrection=cx=0.5:cy=0.5:k1=-0.227:k2=-0.022"— lens correction params
Params k1 and k2 for lenscorrection filter are individual for each camera and can be calculated from H fov, W fov and Diag fov. See a stackoverflow answer for more info.
To fix all *.mp4 files in the directory:
for filename in ./*.mp4; do
[ -e "$filename" ] || continue
ffmpeg -i $filename -map_metadata 0 -c:a copy -c:v h264 -crf 22 -vf "lenscorrection=cx=0.5:cy=0.5:k1=-0.227:k2=-0.022" $filename-fixed.mp4
done