Slyber SFU Server - WebRTC Media Router for Calls, Webinars, and AI Bots

Slyber SFU Server is a high-performance WebRTC Selective Forwarding Unit (SFU) server written in Go. It is designed to handle group video conferences, 1-on-1 calls, live streaming, and voice conversations with AI agents. The server is distributed as a single static binary with zero external dependencies and can be deployed via Docker.

One of the key benefits of an SFU is that it acts as an automated mail sorting center for video and audio streams. Instead of each participant's browser compressing and uploading multiple copies of their video and audio, a single video stream is sent to the server. The server then copies the pre-encoded packets and forwards them to the other participants in the room. This allows a single server node to handle up to 5,000 active rooms simultaneously.

Slyber SFU Server features include a single port (4443) for both UDP and TCP, adaptation to poor internet connections, bandwidth savings in conferences, sub-millisecond peer swapping in 1-on-1 calls, and an /ai/ws gateway for AI voice agents.

The server supports multi-stream Simulcast and the scalable VP9 SVC codec, allowing for up to 3 spatial and 3 temporal layers with automatic spatial layer clamping. It also has a built-in SubscriberBWE bandwidth controller that monitors reports from each viewer and smoothly switches viewers to lighter layers when bandwidth drops or packet loss increases. For conferences, the server reads the audio volume level from the RFC 6464 (ssrc-audio-level) packet header to automatically pause cameras of silent participants.