Live Classes

A self-hosted, low-latency, encrypted live-streaming platform for teaching. Instructors broadcast from a browser or from OBS; students watch on any device with adaptive quality; every class is recorded and replayable.

Built to replace a hosted video platform's per-minute delivery bill with plain nginx bandwidth. Transcoding happens once per class; the thousandth viewer costs the same as the first.

pnpm setup && pnpm up && pnpm db:seed
open http://localhost:8080          # instructor@example.com / changeme-please

What it does

• One-click live streaming — the instructor presses Go Live in the browser (WebRTC/WHIP); students just open a link. OBS and hardware encoders work too, over RTMP or SRT with a stream key.
• Adaptive quality — a GOP-aligned 1080p/720p/480p/360p ladder built by a single ffmpeg process, so switching rungs never stalls. The ladder never upscales a lower-resolution source.
• Low latency — ~3 seconds glass-to-glass on the HLS path, or sub-second over WebRTC for classes that opt into ULTRA mode.
• Encrypted delivery — AES-128 encrypted segments; keys are served only to authenticated viewers holding a live playback session. See docs/security.md, which is specific about what that does and does not protect.
• Access control — public, private link, password, enrolled students, or organization-wide. All five resolved by one function, one test matrix.
• Automatic recording — the replay reuses the live segments, so recording costs essentially nothing and is ready seconds after the class ends.
• Live chat and Q&A — upvoted questions, pinning, moderation, slow mode, fanned out over Redis so it works with any number of API instances.
• Teacher dashboard — schedule classes, manage the roster, watch viewer count and the quality distribution live, browse recordings.
• Web-first — nothing to install for students, works on phones, and iOS Safari's native HLS player is supported without a custom loader.

Layout

apps/api          Fastify: auth, access control, key delivery, chat, hooks
apps/transcoder   ffmpeg supervisor + recording/VOD worker
apps/web          Next.js: player, studio, dashboard, replay library
packages/db       Prisma schema, envelope encryption, seed
packages/shared   zod contracts, WS protocol, ladder, canonical media paths
infra/            compose, mediamtx.yml, nginx, Dockerfiles
scripts/          smoke publisher and end-to-end verifier

Verifying it works

node scripts/smoke-stream.mjs --seconds 120   # publish a synthetic lecture
node scripts/smoke-verify.mjs                 # assert the whole chain
pnpm test && pnpm typecheck

The test pattern carries a burned-in clock, so you can read glass-to-glass latency by putting the browser next to the terminal.

Docs

• Architecture — how it fits together and why
• Deploying and operating — single-box guide, tuning, sizing
• Security model — including what is not protected

Not included

Billing, multi-region edge federation, native mobile apps, DVR scrubbing during a live class, simulcast to YouTube/Facebook, and deep retention analytics. The schema and edge layer leave room for each.