This is a fork of FFmpeg that just adds a video filter to overlay a flootay script onto a video.
In order to enable the flootay filter, make sure you first install the flootay library somewhere so that the FFmpeg configure script can find the pkg-config file. Then enable the dependencies when you configure ffmpeg with a command like this:
./configure --enable-flootay --enable-cairo
Once FFmpeg is built you can use the filter like this:
ffmpeg -i my-input-video.mp4 \
-vf flootay=filename=overlay.flt \
my-output-video.mp4
There is some documentation about the flootay language in the flootay repo.