I would like to be imbed a filter in the Pi’s HDMI output such that pixels are slightly rearranged. Specifically, I’m after a retro pincushion effect (
[ ] -＞
( )). I need it to be active even in the console/boot sequence, thus X11 mods are out.
I realise this is not an easy task, and that I may end up having to modify the DRM or V4L2 driver in order to achieve this. That’s something I would be willing to do if it came to that.
Does anyone have an idea as to how I might be able to go about this? It’s for a Pi Zero and it doesn’t necessarily need to work with a GUI environment.