Real-time camera effects

Design the real-time camera-filter / AR-effects system for a social app where users apply face-tracking lenses and effects live in the camera preview at 30fps on a wide range of phones, and the same effect must render consistently when applied to a captured photo/video server-side (for users on devices too weak to run it live). Effect creators publish new lenses constantly. Design the runtime, the effect distribution, and how you reconcile on-device real-time with server-side rendering.