SFU

An SFU (Selective Forwarding Unit) lets many people watch one device. The device sends one stream to the SFU, and the SFU forwards it to every viewer.

With MQTT or WHEP, each viewer connects to the device directly. More viewers means more connections, more upload bandwidth and more encoding work on the device. With an SFU, the device does the same work for one viewer or for many.

pi-webrtc supports two SFUs:

• LiveKit: host it yourself, or use LiveKit Cloud.
• Cloudflare Realtime: run by Cloudflare.

Both have a free test server below.

Video qualityCopy Anchor Link

The SFU forwards the stream as it is, so every viewer gets the same quality. Set the highest bitrate on the device with --max-bitrate. When the upload is slow, pi-webrtc lowers the resolution and keeps the frame rate.

LiveKitCopy Anchor Link

Free test serverCopy Anchor Link

1. Run on the deviceCopy Anchor Link

./pi-webrtc --camera=libcamera:0 \
    --fps=30 \
    --width=1920 \
    --height=1080 \
    --uid=your-display-name \
    --use-livekit \
    --livekit-url=wss://api.mazupo.com \
    --livekit-key=APIWnQTs4tmUZvA \
    --livekit-room=the-room-name

• --livekit-url: the SFU address. Use wss:// for TLS, or ws:// without TLS.
• --livekit-key: the LiveKit API key.
• --livekit-room: the room to publish to.
• --uid: the name of the device in the room.
• --livekit-secret (sponsor build): creates the LiveKit access token on the device, so you do not need a token server.

Anyone who joins the same room can watch the stream. With --enable-ipc, DataChannel messages also go to everyone in the room.

2. Join the roomCopy Anchor Link

• Code example: Play through the LiveKit SFU
• Web app: app.mazupo.com/room

Cloudflare RealtimeCopy Anchor Link

Free test serverCopy Anchor Link

1. Run on the deviceCopy Anchor Link

./pi-webrtc --camera=libcamera:0 \
    --fps=30 \
    --width=1920 \
    --height=1080 \
    --uid=your-display-name \
    --use-cloudflare \
    --api-url=https://api.mazupo.com \
    --api-key=81f899b8fab5692b0faa76c3372b7ae6

The device connects to Cloudflare Realtime through the Mazupo API. Cloudflare gives the device a new session each time it reconnects, and the API links that session to the device's uid.

• --api-url: the API address.
• --api-key: the key that lets the device use the API.
• --uid: the device name. Anyone who knows it can find the stream.

Cloudflare Realtime does not carry DataChannel or IPC messages yet. --enable-ipc still works for the other signaling that you turn on.

2. Watch the streamCopy Anchor Link

• Code example: Pull from the Cloudflare Realtime SFU
• Web app: open app.mazupo.com/cloudflare. Under Settings → Network, enter the URL and the Viewer API key. Add a device with the same uid, then select it.

Keep device control with MQTTCopy Anchor Link

SFU viewers do not get the built-in command and stream DataChannels. So snapshots, recording control, camera control and file transfer only work over MQTT. You can turn on --use-mqtt together with an SFU: the SFU carries the viewers, and MQTT keeps those commands. See DataChannels.