Convert movie into animated gif.

Video to Images

Make sure not to make the resolution or duration extreme. Convert the movie into 3 digits indexed images.

One command

ffmpeg -i godot-shader.mov -r 15 godot-shader.gif

Making images to preprocess

ffmpeg -i video-720.mov -r 15 image-%3d.png

Weed out the duplicates

Remove unneeded images from the video manually.