Code Room
System designHardsd-g505
Subject Video streamingLevel Senior–Staff~45 minCommon in Distributed systems interviewsIndustries Computer games, Technology

Question

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.

What a strong answer looks like

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.

Narrate your design
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Run or narrate your approach, then ask the coach.