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Problem Understanding
Restate the problem in your own words.
Design YouTube / Netflix
Design a YouTube- or Netflix-class video streaming system: ingest user (or studio) uploads, encode them at multiple bitrates, store the segments durably, distribute via a multi-CDN, and play them back with sub-1-second start latency on devices ranging from 4K TVs to 3G mobile. The decisive trade-offs are the encoding ladder (cost vs. quality vs. ABR shape), the CDN cache hit ratio (cost vs. user latency), and — if live is in scope — the dramatically different ingest path that has to deliver in seconds.
- YouTube~500 hours uploaded per minute; the canonical UGC streaming case. Encode-and-CDN pipeline at hyperscale.
- NetflixStudio-quality VOD, AV1 + per-shot encoding, OpenConnect CDN inside ISP networks.
- TwitchLive-first; sub-2-sec end-to-end latency target. A different ingest + packaging path than VOD.
- Disney+ / HuluStudio-grade VOD on a third-party CDN — the same encoding ladder, slightly different DRM and rights story.
Your task: read the problem above, then write what the system is, who uses it, the rough scale, and the headline UX expectation — in your own words. Submit for AI review when you're ready.
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