Video calls, like Zoom
Peer to peer for two, an SFU for a meeting, signaling and what happens on a bad network.
What is on this board
Parts
- Host Desktop app
- Guest Mobile app
- Signaling WebSocket / realtime server
- TURN Reverse proxy
- SFU Service · WebRTC
- Rooms Key-value store · Redis
- Recording Media processor
- Recordings Object storage · S3
- Sign-in Identity provider
- An SFU, not a mixer Decision record
How they connect
- Host → Signaling: join room
- Guest → Signaling: join room
- Signaling → Rooms: members
- Signaling → Sign-in: who is this?
- Host → SFU: my video
- SFU → Guest: video
- Guest → TURN: behind a firewall
- TURN → SFU: relay
- SFU → Recording: record
- Recording → Recordings: save
Notes and decisions
- Signaling: Who is in the room, how to reach them
- TURN: A relay when a firewall blocks direct traffic
- SFU: Forwards streams, never mixes them
- An SFU, not a mixer: Each person sends one stream in several qualities, and each receiver gets what fits their network. Far cheaper than mixing video on the server.
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