Umbra 0.5.1 for Linux

Umbra for Linux, as one Flatpak bundle. This release is for Linux only; the Windows host stays on Umbra 0.5.0.

Install guide: Umbra on Linux · HDR extras

What's new on Linux

• One Flatpak for x86_64 Linux. It replaces the Ubuntu 22.04/24.04 .deb packages of 0.5.0.
• A virtual display for every stream on KDE Plasma and GNOME (Wayland), created by the desktop at the size and refresh rate Eclipse asks for, as Umbra does on Windows.
• Co-op: a Linux host can be one of the two co-op PCs. Tested alongside a Windows host running Umbra 0.5.0.
• GPU frames end to end. NVIDIA encodes with NVENC. AMD encodes ordinary streams with VA-API, and co-op panes with Umbra's GPU HEVC encoder on OpenCL. On both, frames stay on the GPU.
• HDR on KDE's and GNOME's virtual displays, with the optional HDR extras below.
• Input Setup: one administrator prompt installs the input rule streamed controllers, mouse and keyboard need, with an option to start Umbra when you sign in.

Downloads

File	What it is
Umbra-0.5.1-linux-x86_64.flatpak (+ .sha256)	Umbra for Linux
Umbra-HDR-KDE-ubuntu26.04.tar.gz	Optional. Patched KWin 6.6.6 packages for Ubuntu 26.04: HDR on KDE virtual displays. Steps in its README.txt; other distributions see Known limits
Umbra-HDR-GNOME-ubuntu26.04.tar.gz	Optional. Patched Mutter 50.1 packages for Ubuntu 26.04: HDR on GNOME virtual monitors. Steps in its README.txt; other distributions see Known limits
Umbra-HDR-KDE-ubuntu26.04-source.tar.gz, Umbra-HDR-GNOME-ubuntu26.04-source.tar.gz	Source packages of the HDR extras (Ubuntu's source plus one patch each)
umbra-linux-0.5.1-project-source.tar.gz	Umbra's source at this release, with how the bundle was built
Umbra-0.5.1-linux-flatpak-sources.tar.gz	Every third-party source the Flatpak build fetched (NVIDIA's CUDA compiler components are listed, not included)
SHA256SUMS	Checksums for every file above

Install

sudo apt install flatpak
flatpak remote-add --user --if-not-exists flathub https://dl.flathub.org/repo/flathub.flatpakrepo
sha256sum -c Umbra-0.5.1-linux-x86_64.flatpak.sha256
flatpak install --user Umbra-0.5.1-linux-x86_64.flatpak

Start Umbra from the applications menu, accept Input Setup, open https://localhost:47990 to create the administrator login, and pair Eclipse with its PIN. If you used the 0.5.0 .deb, remove it first (systemctl --user disable --now sunshine, then sudo apt remove umbra) and pair Eclipse again: the Flatpak keeps its own settings.

What was tested

Desktop	Streaming	Own virtual display per stream	Co-op	HDR
KDE Plasma on Wayland (Ubuntu 26.04, KWin 6.6.6)	Yes	Yes	Yes	With the KDE HDR extra
GNOME on Wayland (Ubuntu 26.04, Mutter 50.1)	Yes	Yes	Yes	With the GNOME HDR extra; a physical HDR monitor streams HDR without it
X11 desktops (Cinnamon, Xfce, MATE …)	Yes (tested during development on Linux Mint 22.3)	No	No	No
Sway, Hyprland and other wlroots desktops, COSMIC	Not supported

• GPUs: NVIDIA RTX 2060 SUPER (driver 595) and AMD Radeon RX Vega. Intel GPUs and PCs with more than one GPU are untested.
• Other distributions running KDE Plasma or GNOME on Wayland are expected to behave like those rows but are untested. Two Linux hosts in one co-op session are untested.

Known limits

• AMD: the only AMD card available for testing is a Radeon RX Vega from 2017. Its video encoder reaches about 60 fps at 4K and 165 fps only at 1080p, and its co-op panes run at about 35 fps. The same card hit the same 4K limit on Windows (62 fps), so its age, not Umbra, is the likely limit; newer AMD cards could not be tested. It has no 10-bit encoder, so its ordinary streams are SDR (co-op HDR works through the GPU HEVC encoder).
• HDR extras are patches to KWin 6.6.6 and Mutter 50.1, tested on Ubuntu 26.04 like the Flatpak. Both apply unchanged to KDE's and GNOME's own 6.6.6 and 50.1 releases, so other distributions shipping those versions are expected to work but are untested: add the KWin patch or Mutter patch to your distribution's own package and rebuild it. The prebuilt packages here are for Ubuntu 26.04. Either way they replace the desktop's compositor packages; a distribution update of KWin or Mutter replaces them again and streams return to SDR. Reinstalling the distribution's package undoes them (each Ubuntu README.txt has the command).
• X11 has no way to create a display while it runs, so the host streams the desktop there but never offers co-op or HDR.

Umbra 0.5.0

Umbra 0.5.0 is the first packaged release of Umbra, the host side of the Eclipse + Umbra project. It is a thin fork of Apollo (itself based on Sunshine): normal hosting behaves like Apollo, and Umbra adds what Eclipse's two-PC co-op needs. Pair it with Eclipse 1.3.0.

Built from a076a7c0. The host reports version 0.5.0 and that commit.

Downloads

Platform	Asset	Notes
Windows x64 (installer)	Umbra-windows-x64.exe	Installs the host service, the SudoVDA virtual display driver, the ViGEm virtual gamepad bus, firewall rules and the GPU HEVC co-op encoder. Needs administrator rights.
Windows x64 (portable)	Umbra-windows-x64.zip	Same payload, without the installer's driver and service setup.
Ubuntu 24.04 amd64	Umbra-0.5.0-ubuntu24.04-amd64.deb	Install with sudo apt install ./Umbra-0.5.0-ubuntu24.04-amd64.deb so dependencies resolve.
Ubuntu 22.04 amd64	Umbra-0.5.0-ubuntu22.04-amd64.deb	As above. These are two separate build baselines, not one universal Linux binary.

Each asset has a matching .sha256 file, and SHA256SUMS covers everything.

Umbra replaces Apollo in place (same install folder and registry key), and installing Apollo later replaces Umbra. Closing the settings page in your browser leaves hosting running, as in Apollo. Use the tray icon's Quit or stop the service to stop it.

What Umbra adds

• Built-in Co-op Pane: a hidden app that Eclipse uses for two-PC co-op, with per-launch co-op encoder tuning applied to that session only.
• GPU HEVC co-op encoder: lets an NVIDIA PC and an AMD PC share one co-op picture. The serverinfo UmbraCaps bit 3 tells Eclipse it is installed.
• Host monitor off on request, wired-path pinning, and host logs a paired Eclipse can include in a support bundle.
• Owned-only cleanup: Exit/Stop and uninstall stop only this installation's service and processes. Shared drivers are kept unless you choose to remove them, and you choose whether to keep settings.

Fixed during release testing

• Mixed-GPU co-op was unavailable in release builds. Removing the beta-only per-client profile feature also compiled out the GPU HEVC session request and its capability bit, so hosts reported UmbraCaps 23 instead of 31. Fixed in aab15c04.
• Uninstall or upgrade could hang forever. When the system PATH ended in a backslash (Windows' stock last entry, ...\System32\OpenSSH\, does), the inherited update-path.bat passed reg add a quote that the backslash escaped. reg then waited for an answer nobody could see. Fixed in a076a7c0.

Tested

• Windows 11, three PCs (two NVIDIA, one AMD): a clean install after removing the previous host, its drivers, driver-store packages and certificate. Install finished in 13–78 s with no reboot required. The service, virtual display and virtual gamepad devices, firewall rules and listening ports all came up. A service stop/start left no stray processes or ports.
• Upgrade in place, using this build's own uninstaller, on a PATH ending in OpenSSH\. It finished in 17 s, and settings and pairings were kept. All three hosts report UmbraCaps 31.
• With Eclipse 1.3.0 on an LG G5: a live 4K HEVC single-host stream, and NVIDIA + AMD co-op with both hosts on the GPU HEVC encoder (3840×2176, 0% frame drop). Quit freed both hosts.
• Ubuntu 22.04/24.04: package contents, dependency resolution and install/upgrade/remove/purge in disposable environments. A live hardware test was done on an earlier Ubuntu 24.04 build.

Known issues

• Upgrading from Apollo or an older Umbra can still hang on PCs whose PATH ends in a backslash. The old version's uninstaller runs first and still has the PATH bug fixed above. If setup stops making progress for more than a minute, end reg.exe in Task Manager (Details tab) and setup continues. Or first uninstall the old version from Apps & features, ending reg.exe the same way if needed, then install Umbra.
• The Windows installer is unsigned. Windows SmartScreen may warn. The bundled kernel drivers (SudoVDA, ViGEm) carry their own vendors' signatures.
• Fatal: GameStream is still enabled in GeForce Experience! can appear in the log on PCs that once had an NVIDIA card. This is inherited from upstream and is triggered by a leftover NVIDIA registry value. It did not affect streaming in testing.

Source

umbra-project-source.tar.gz (this repository at the release commit, with pinned submodules) and umbra-external-source.tar.gz (third-party dependency sources) are attached. Umbra is GPL-3.0, like Apollo and Sunshine. This project is developed with AI assistance (Claude and Codex write and debug code under the maintainer's direction and hands-on testing).