System designHardsd-g487

Subject Adaptive bitrateLevel Senior–Staff~45 minCommon in Code quality & review interviewsIndustries Technology, Software development

Question

Design the per-title (and per-shot) encoding-optimization service that decides the ABR ladder for each title rather than using one fixed resolution/bitrate ladder for the whole catalog. A flat ladder over-spends bits on simple content (a talking-head cartoon) and under-delivers on complex content (a fast-action sports clip). The service must analyze each title's complexity, choose the rungs (resolution+bitrate pairs) that sit on the quality-vs-bitrate convex hull, and do it cheaply enough to run on every one of millions of titles.

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.