Broadcast Control
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Two PCs and the SM Bridge

Run the game on one PC and the broadcast on another.

One PC or two

On one PC, the app reads the game directly. With two, the game runs on one PC and the app on another, and the SM Bridge carries the data that only exists on the game PC.

One PC setup Le Mans Ultimate's web server feeds LMU Broadcast Control over REST on port 6397 and WebSocket on 6398. The app serves overlays to OBS browser sources at localhost:5111. The Stream Deck plugin talks to the same local server. Your PC Le Mans Ultimate web server REST 6397 · WS 6398 LMU Broadcast Control timing · replays · cameras localhost:5111 OBS browser sources Stream Deck plugin localhost:5111
Two PC setup with the SM Bridge On the game PC, Le Mans Ultimate's web server is reached over the network on REST port 6397 and WebSocket port 6398. The SM Bridge, also on the game PC, reads shared memory and streams it over TCP port 5200 with a token. On the broadcast PC, LMU Broadcast Control takes both feeds and serves overlays to OBS on port 5111. Game PC Broadcast PC Le Mans Ultimate web server shared memory SM Bridge streams shared memory REST 6397 · WS 6398 TCP 5200 · token LMU Broadcast Control :5111 OBS browser sources

Connecting to the game PC

  1. On the game PC, make sure ports 6397 (REST) and 6398 (WebSocket) can be reached from your network.
  2. On the broadcast PC, enter the game PC's IP address and port in a PC card on the Home screen.
  3. Click Connect. The chip at the top of the PC card turns green and reads Connected.
  4. Open the windows you need from that PC's card.

On the PC that runs the game itself, you can enter localhost, the Windows machine name or its LAN IP (for example 192.168.1.10). All three count as local, so the app reads shared memory directly instead of through the SM Bridge. That lets you use the same settings on both PCs.

What the SM Bridge adds

Some data only exists in shared memory on the game PC. The SM Bridge runs there and streams it to the app over your network. It adds:

  • per-corner tyre compounds, shown as a 2×2 grid when a car runs different tyres left and right (front and rear compounds work without it);
  • a smooth track map, with 150ms position updates instead of one second;
  • yellow flags per sector (S1, S2, S3);
  • shared-memory collision detection;
  • the game's own penalty type and reason (SM Bridge 0.0.6 or later).

Contacts don't need it: they come from the game's own incident list (Le Mans Ultimate 1.4.1 or later), which a second PC reads without the bridge.

The bridge is only for two-PC setups. On a single PC the app reads shared memory directly.

Setting up the SM Bridge

  1. In the app's install directory, the SM Bridge folder holds the bridge's installer (LMU.SM.Bridge-<version>-setup.exe); it's also on the release page. Copy it to the game PC and run it. It installs to %LOCALAPPDATA%\LMU SM Bridge\ and adds a Start Menu group.
  2. Start the bridge from the Start Menu. With the default settings it accepts connections from your network straight away. It doesn't need the game running; it connects when the game starts.
  3. Accept the Windows prompts the first time. The bridge registers itself and adds its own firewall rule for its port, and won't ask again. If you decline, it only accepts connections from its own PC and tells you how to fix it.
  4. On the broadcast PC, enter the game PC's IP address and the bridge port (5200 by default) in the PC2 card, then connect.

Settings

To change a setting, edit %LOCALAPPDATA%\LMU SM Bridge\settings.json in any text editor and restart the bridge.

Setting What it does
port The port it listens on, 5200 by default. Use the same port in the PC2 card
token Optional shared secret. Without one, any PC on your network can connect. Set one on shared or event networks, treat it like a password, and enter the same token in the PC2 card
allowRemote true (the default) accepts connections from your network; false only from the game PC itself, for testing

Keep the bridge on your local network; never expose it to the internet.

Firewall

The bridge adds its own inbound firewall rule on first run, and moves it if you change the port. Windows lists the bridge as "System", so an app rule does nothing: if you add a rule yourself, make it a port rule. In PowerShell as administrator, with your port:

New-NetFirewallRule -DisplayName "LMU SM Bridge" -Direction Inbound -Action Allow -Protocol TCP -LocalPort 5200

Also make sure the network profile is set to Private.

The SM Bridge doesn't count towards a paid plan's device limit.

Ports

Port Used for Where
6397 Game web server, REST Game PC
6398 Game web server, WebSocket Game PC
5200 SM Bridge (default) Game PC
5111 Overlay and Stream Deck plugin Broadcast PC, while Overlay Controls is open

If the app log shows Bridge ... returned HTTP 400, the bridge only accepts connections from its own PC: set "allowRemote": true and restart it.

If the bridge stops at start with "Access is denied", Windows has reserved its port. Check with netsh int ipv4 show excludedportrange protocol=tcp, pick a port outside those ranges (for example 5300), restart the bridge and use the new port in the PC2 card.

The bridge writes a log for every run to %LOCALAPPDATA%\LMU SM Bridge\logs\. Send it with a bug report.