Use one computer's camera and microphone on another.
AV Relay has two sides. The sender shares its camera and microphone. The receiver shows them as an ordinary webcam and microphone, AV Relay Camera and AV Relay Microphone, so every app can use them: Firefox, Chrome, Discord, Zoom, OBS, … Today the sender runs on a Mac and the receiver on Ubuntu or Windows, on the same network. The initial Windows receiver uses OBS Virtual Camera and VB-CABLE.
- On demand. The sender's camera and microphone run only while an app on the receiver uses them. Close the call and the camera light goes out.
- Pair once. A 6-digit code shown on the sender, typed on the receiver. After that the two find each other on their own, even if an address changes.
- Private. Nothing leaves your network: no account, no cloud. Everything between the two computers is encrypted end to end.
- Out of the way. Both start at login and live in the menu bar or top bar. While the sender is connected, its microphone is the receiver's default input; when it goes away, your previous one comes back.
Install the sender on the computer whose camera and microphone you want to use, and the receiver on the computer where you want them.
| Your computer | Sender: shares its camera and microphone | Receiver: uses them as a webcam and microphone |
|---|---|---|
| macOS 14 or newer | Install the sender | Not yet |
| Ubuntu 24.04 | Not yet | Install the receiver |
| Windows 10/11 x64 | Not yet | Install the receiver |
Download from the latest release. Then pair the two.
You need macOS 14 or newer.
- Open
AV-Relay-<version>-macOS.dmgand drag AV Relay to Applications. (Start it from Applications: the login item remembers where the app is.) - Open it. The first time, macOS says it can't check the app for malware, because it isn't signed with an Apple Developer ID. Go to System Settings → Privacy & Security and click Open Anyway.
- AV Relay appears in the menu bar and turns Open at Login on. When macOS asks whether it may use the local network, allow it; it asks for camera and microphone permission the first time a receiver uses them.
More, including troubleshooting: docs/macos.md.
You need Ubuntu 24.04 (GNOME) and the v4l2loopback kernel module, version 0.13 or newer. With Ubuntu's HWE kernel (the default on 24.04.2 and later) that's one extra package:
sudo apt install ./av-relay_<version>_amd64.deb linux-modules-v4l2loopback-generic-hwe-24.04
Then restart (or log out and back in). AV Relay starts at every login and shows its icon in the top bar. To start it right away, open AV Relay from the app grid.
Not on the HWE kernel, or the camera says it's unavailable? See docs/linux.md. Other recent Linux desktops with PipeWire may work too, but aren't tested.
More, including troubleshooting: docs/linux.md.
Windows setup and pairing: Windows receiver guide. It uses OBS Virtual Camera and VB-CABLE. Camera capture follows app usage; microphone capture uses a manual switch. The pairing steps below describe the Ubuntu receiver.
- On the sender: click the AV Relay icon in the menu bar → Allow Pairing…. It shows a 6-digit code, its address and its port.
- On the receiver: click the AV Relay icon in the top bar → Pair with a sender…. Under Auto-discovery, pick the sender (or type its address and port under Manual), click Continue, and type the code.
That's it. The sender's pairing window then shows Paired with and the receiver's name; from now on the two connect by themselves whenever both are on. A receiver uses one sender; a sender can be paired with several receivers and serves one at a time.
In your app's settings, choose AV Relay Camera and AV Relay Microphone. The microphone is already the default input while the sender is connected; most apps remember the camera you chose.
If the sender drops off (sleep, Wi-Fi), the camera and microphone stay for 5 minutes, the camera showing a "Waiting for connection…" picture, so a short drop doesn't break your call. Turn on Keep virtual devices on to keep them for good.
Each side's menu shows whether they're connected and whether the camera and microphone are in use. Enable AV Relay at the top switches a side off without quitting it, as if it were closed, and back on. On the receiver you can also pick the camera quality (1080p or 720p), turn Start at login or Start minimized off, pair with a different sender, or forget this one.
sender (server) receiver (client)
───────────────── ───────────────────────────────
camera ─┐ ┌─► "AV Relay Camera" (webcam)
├─ H.264 / Opus ── WebRTC over your LAN ───┤
mic ────┘ encrypted, paired with a code └─► "AV Relay Microphone" (input)
When an app on the receiver opens the camera or the microphone, AV Relay asks the sender to start it; when the app lets go, the sender stops a few seconds later. Video is H.264, encoded in hardware on the Mac (up to 1080p at 30 fps); audio is Opus. The receiver plays both a little after they were captured: just long enough to cover the network's usual hiccups (0.2 s on a calm network, up to 2 s while Wi-Fi stalls keep coming back), the same for sound and picture, so they stay smooth and in step. The details are in docs/architecture.md and the wire protocol in docs/protocol.md.
A MacBook Air (M4) with macOS 27 as the sender and Ubuntu 24.04 as the receiver, over Wi-Fi.
- Sender for macOS: server/macos (Swift)
- Receiver for Linux: client/linux (Rust) and docs/linux.md
- Receiver for Windows: client/windows (Rust, native Win32 UI)
- Both follow docs/protocol.md and test against the shared vectors in tests/vectors.
- What changed in each release: CHANGELOG.md; how a release is made: docs/releasing.md.