- Use any screen recorder to record the screen. Gnome has a built-in recorder that is started and stopped with ctrl+shift+alt+r.
- Use kdenlive's edgecrop and speed effects to crop and adjust speed as required. render as mp4.
- Convert MP4 to several images:
sudo ffmpeg -i save_project.mp4 -r 20 'frames/frame-%03d.jpg'
- Use gimp to determine coordinates of required crop