found via reddit

https://gitlab.com/Canta/ffmpeg_shadertoy_filter

I wonder if it works with Cingg? (it looks simple enough on command line), but i have no idea how it will interact with say opengl output..) Can't test on my limited environment, sorry (there is xwayland-based  experimental project [0] with packages for termux, but i am a but short on flash space  right now for trying it..) 

[0] - https://github.com/suhan-paradkar/termux-wayland/wiki/Launching-GUI-applications