System designHardsd-g244

Subject TranscodingLevel Senior–Staff~50 minCommon in Distributed systems interviewsIndustries Technology

Question

Design the transcoding pipeline behind a UGC video platform ingesting 500 hours of new video per minute. Each upload must be fanned out into ~8 renditions (multiple resolutions + codecs) plus a thumbnail set, and the median upload must be playable within 60s while a 4-hour 4K upload may take much longer. Cost-sensitive: you run a fleet of mixed GPU and CPU workers and want >70% utilization. Design the job graph, scheduling, and how you keep p50 latency low without starving long jobs.

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.

Learn the concepts

Narrate your design

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Run or narrate your approach, then ask the coach.