The pipeline, documented.
Uploads run through ffmpeg.wasm in the browser. The ladder targets the short edge (360 / 720 / 1080), never upscales, encodes libx264 main profile with +faststart and AAC audio, then uploads each rendition alongside the original.
Rendition metadata is stored per video as { height, label, path, bytes, codec } so the player can offer a quality menu.
Retrieval: category affinity, follow graph, recency, watch de-duplication. Ranking: engagement rate per view, view velocity per hour, duration-weighted retention, boost, cold-start trial tier.
Shorts are ranked separately on loop and share proxies rather than click-through.
Live streaming is peer-to-peer WebRTC with a signalling channel over realtime broadcast. Counters (views, likes, comments) are pushed on row changes rather than polled.