Use custom GLSL shaders to batch process a lot of images. It's intended for use on two video files, one representing the foreground and the other representing the background, with frames extracted as png format.
ideal command to convert a video to frames is:
ffmpeg -i generic.mov -r [framerate] -f image2 [folder]%05d.png where framerate is the framerate at which the frames will be generated, and folder is "in_fg" or "in_bg"
ideal command to convert frames to a video: ffmpeg -framerate 30 -i out/%05d.png video.MOV
Requires raylib and C++17 filesystem header. Get raylib from https://github.com/raysan5/raylib/ or ur local linux distro's repositories.
I plan to make this more easy to use and powerful in the future, with more example shaders, and with a preprocessor to add the supporting GLSL functions to any input shader. Also might add a GUI using raygui.