Game replay rendering
Design the automatic game-replay/highlight capture and rendering system for a competitive multiplayer game with 5M daily matches. Rather than recording raw video (huge, per-client), the game streams a compact event/state log of each match; your backend must store these logs, detect highlight-worthy moments (a clutch play, a multi-kill), and on demand RENDER selected clips to shareable video by replaying the log through a headless game engine. Storing video for every match is infeasible; rendering on demand is GPU-expensive. Balance storage, compute, and latency-to-share.
Clarify scale and constraints first. Propose a clean component breakdown, then go deep on the hard parts (data model, bottlenecks, consistency, failure modes) and name the trade-offs you are making.