Media

Ingesting, transcoding, and delivering video and other heavy media at scale: parallel encode pipelines, adaptive bitrate ladders, and the CDN economics that decide what delivery costs.

Explainers

• Design a Video Platform — Someone uploads a 4K clip; seconds later millions can stream it on a train, a laptop, a TV — and the bill to deliver it dwarfs the bill to store it. Built from zero: a commit-first envelope on the CDN egress bill (5M users × 5 plays × 300 MB is 7.5 PB a day, and the number should scare you), why one server melts, the two-lane upload with pre-signed URLs writing straight to storage and GOP-aligned resumable segments, the heart — transcoding as a DAG of tasks where every segment × resolution encodes in parallel and a dead worker costs one segment not one video, adaptive bitrate over a per-title ladder with the player choosing rung by rung, CDN economics and the long tail (cache the hot set, serve the cold tail from origin, lazily transcode what nobody watches) — then the failure sweep whose sharpest box is a poison video that turns your own idempotent retry into a fleet-killer.