lightmime

Sync Philips Hue lights with your screen on Linux.

lightmime watches what is on your screen and colours the lights of a Hue entertainment area to match it, the way Hue Sync does on other systems. It streams over the bridge's Entertainment API, so the lights follow the picture with low latency.

• A small window and a tray icon: pair with the bridge, pick an area, start syncing and tune brightness, smoothing and saturation while it runs. See Window and tray.
• Made for Wayland: capture goes through the screen-cast portal and PipeWire, on KDE Plasma, GNOME and wlroots compositors (Hyprland included). You pick the screen once.
• Keybindings and status bars: lightmime toggle and a Waybar module through lightmime status --waybar --follow. See Hyprland and Omarchy.
• Headless if you like: lightmime run as a systemd user service.
• Home Assistant, optionally: turn on MQTT and lightmime appears as a device with a sync switch, a status sensor and sliders. See Home Assistant.
• Light on resources: one Rust binary that scales each frame down to 64×36 pixels before touching it. While syncing at 30 fps it uses about 1 % of one CPU core and 36 MB of memory (measurement).

Install

flatpak install --user https://lightmime.pataar.nl/flatpak/lightmime.flatpakref

Release binaries and building from source are under Install. Then follow the Quickstart: pair, choose an area, press Start.

This adds lightmime's Flatpak repository, so flatpak update brings new releases; the runtime comes from Flathub.

You need a Hue bridge with an entertainment area set up in the Hue app, and a desktop with PipeWire and an xdg-desktop-portal backend that offers screen casting. You don't need a Hue Sync Box or a Hue account: lightmime pairs with the bridge on your network.

From the command line

lightmime pair --host 192.168.1.20   # press the bridge's link button when asked
lightmime areas                      # list entertainment areas
lightmime use-area "TV area"         # pick one
lightmime test                       # 8-second colour sweep, no screen capture
lightmime run --start                # capture and sync until Ctrl-C
lightmime gui                        # the window and tray icon
lightmime toggle                     # start or stop the running lightmime, for a keybinding

See the CLI reference and Configuration.

Desktop integration

The Flatpak brings its launcher entry and icons. For a binary or source install, add them for the launcher entry, window icon and tray icon:

install -Dm644 contrib/io.github.pataar.lightmime.desktop ~/.local/share/applications/io.github.pataar.lightmime.desktop
cp -r assets/icons/hicolor ~/.local/share/icons/

How it works

1. Capture: ScreenCast portal → PipeWire node → GStreamer (pipewiresrc ! videoconvert ! videoscale) → 64×36 RGB frames.
2. Mapping: each entertainment channel samples the screen region matching its position in the area (x = left/right, z = bottom/top), averaged in linear light, then saturation, smoothing and brightness are applied.
3. Streaming: the area is started through the CLIP v2 API, then HueStream v2 messages go out over DTLS 1.2 (PSK, PSK-AES128-GCM-SHA256) to UDP port 2100, one datagram per frame.

More in How it works.

Build your own frontend

The engine is a separate crate, lightmime-core, with no user interface: capture, colour mapping, pairing, area listing and streaming behind a small Engine handle. The bundled window, daemon and CLI use nothing else, so a GTK, Qt or web frontend can do the same. examples/minimal.rs pairs, picks an area and syncs in about 70 lines.

Compared with Lumux and HyperHDR

	lightmime	Lumux	HyperHDR
Written in	Rust	Python (GTK4 / libadwaita)	C++
Lights	Philips Hue	Philips Hue	Hue, LIFX, WLED, LED strips over serial/SPI, and more
Screen capture on Wayland	Portal + PipeWire	Portal	Portal + PipeWire, also USB HDMI grabbers
Interface	Window, tray, CLI	Window, tray	Web interface
Runs headless	Yes, also as a systemd user service	No	Yes, but PipeWire capture needs it to run as a user app, not a system service
Home Assistant	MQTT discovery	No	MQTT
Platforms	Linux	Linux	Linux, Windows, macOS

Pick HyperHDR if you drive LED strips, use an HDMI grabber or want HDR tone mapping; it does much more. lightmime does one thing, Hue sync from a Linux desktop, with as little setup and overhead as possible. More in Compared with other tools.

Contributing

Bug reports and pull requests are welcome; see CONTRIBUTING.md. AGENTS.md describes the architecture, protocol notes and the Home Assistant contract. Logo, icons and colours are in assets/brand/.

Licence

Licensed under either of MIT or Apache-2.0, at your option. lightmime is not affiliated with Signify or Philips Hue.