video - Is there a way to remove GoPro fisheye using ffmpeg -


it seems possible compensate fisheye distortion using ffmpeg lenscorrection filter:

ffmpeg -i in.mp4 -vf "lenscorrection=cx=0.5:cy=0.5:k1=-.25:k2=-.25" out.mp4

what values k1 , k2, particularly gopro? there way compute them?

i don't think there's generic 1 setting(s) cover gopro models & lenses. factor in people can use customised/replacement lenses.

i hoping example image featuring what have work with, never mind...
hope below useful in way

check link gopro hero 3 settings (applies other models). rough idea of best k1 , k2 values, should find nearest aspect ratio image resolution then...

divide h. fov deg v. fov deg , multiply result diag. fov deg.

example: where picture size 1920 x 1080 : makes 16:9 widescreen.

gopro 3 setting: 16 x 9 widescreen :: h fov = 69.5 || v fov = 118.2 || diag = 133.6

so 118.2 / 69.5 * 133.6 = 227.216 etc

for k1 result integer 227 (drop decimal points).

for k2 value 0.022 seems universal (all test images), can try k2=-.022.

for cx , cy keep them : cx=0.5:cy=0.5:.

example:

ffmpeg -i in.mp4 -vf "lenscorrection=cx=0.5:cy=0.5:k1=-0.227:k2=-0.022" out.mp4

result : (original image found via google images of gopro hero-2 video).


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