LyricDisplay NDI™ Companion

Headless Electron application that broadcasts LyricDisplay output pages over NDI® for use in OBS, vMix, and other NDI-capable production software.

How it works

1. The main LyricDisplay app launches this companion automatically.
2. The companion opens invisible (offscreen) browser windows that load the same output pages you see on screen.
3. Each frame is captured via Chromium's offscreen rendering and sent over NDI using the grandi native module.
4. NDI receivers on the local network (OBS, vMix, Wirecast, etc.) pick up the streams with full transparency support.

Installation

End users do not need to install this manually. The main LyricDisplay app downloads, installs, and manages the companion automatically from the NDI settings panel.

For development

cd lyricdisplay-ndi
npm install

The companion is launched automatically by the main app during development. You can also run it standalone:

npx electron . --host 127.0.0.1 --port 9137 --app-url http://localhost:5173 --no-hash

CLI options

Flag	Default	Description
--host <ip>	127.0.0.1	IPC server bind address
--port <port>	9137	IPC server port
--app-url <url>	http://127.0.0.1:4000	Base URL of the LyricDisplay backend
--no-hash	(hash routing)	Use path-based routing (for dev with Vite)

Building

npm run build

Produces a platform-specific .zip archive in dist/ via electron-builder.

Releasing

npm run release

Bumps the version, commits, tags, and pushes. GitHub Actions builds and uploads platform archives to the release.

Architecture

src/
  main.js           – Electron entry point
  cli.js            – CLI argument parser
  settings.js       – Persistent settings (electron-store)
  outputManager.js  – Offscreen BrowserWindow lifecycle and frame capture
  ndiSender.js      – grandi NDI sender wrapper
  ipc.js            – TCP JSON-line protocol server

Trademarks

NDI® is a registered trademark of Vizrt NDI AB. This project is not affiliated with or endorsed by Vizrt NDI AB. For more information about NDI, visit ndi.video.

License

This project is part of LyricDisplay and is licensed under the GNU General Public License, version 3 or later. See the main repository for full license details.