enricobuehler
3f96e96106
Drop the "Linux-first" framing across the README and docs site in favor of first-class Linux AND Windows hosts, and surface the Windows IDD-push virtual-display path as a distinct differentiator (punktfunk's own indirect display driver the host pushes frames into — a real virtual display, no physical monitor or dummy plug, even on the secure desktop). Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
5.1 KiB
title, description
| title | description |
|---|---|
| Windows Host | Run the punktfunk streaming host on a Windows PC — a first-class, virtual-display host. |
Status: implemented and shipping — x64-only. Alongside the Linux host, punktfunk runs as a
first-class native Windows host: a signed installer registers a LocalSystem service that streams
your Windows desktop or games to any punktfunk or Moonlight client, at the client's exact resolution
via a virtual display — including HDR10 (10-bit BT.2020 PQ) when your Windows desktop is in HDR
mode. punktfunk has its own indirect display driver (IDD) that the host pushes finished frames
straight into, so you get a real on-the-fly virtual display with no physical monitor or dummy HDMI
plug — even on the secure desktop (UAC / lock screen). The Windows host is newer and less
battle-tested than the Linux host. (The Linux host is 8-bit only — HDR there is blocked upstream.)
This page is about the Windows host (streaming from a Windows PC). To stream to a Windows PC, see the Windows client.
Requirements
- Windows 10/11, x64. ARM64 is not supported — both NVENC and the virtual-display driver are x64-only.
- An NVIDIA GPU + driver. The host encodes with NVENC (
nvEncodeAPI64.dll); there is no other encoder backend on Windows. - (Optional) ViGEmBus for virtual gamepads — a manual prerequisite for now (releases).
Install
Download the signed punktfunk-host-setup-<ver>.exe from the package registry and run it — it
installs the host into C:\Program Files\punktfunk, optionally installs the bundled SudoVDA
virtual-display driver, and registers + starts the service. Full steps (including the silent install
and the CLI punktfunk-host service install path) are in
Running as a Service → Windows; packaging internals live in
packaging/windows.
The installer also sets up the web management console (status, paired devices, the PIN pairing
flow): it bundles the console plus its own bun runtime and runs it as the PunktfunkWeb service
on http://<this-PC>:3000, starting at boot. During setup you choose the console login
password (pre-filled with a secure random default and shown again on the final page); change it
later in %ProgramData%\punktfunk\web-password. Open the console from any browser on the LAN and log
in — no extra install, and the host's management API stays loopback-only behind it.
How it works
The host installs a LocalSystem SCM service that runs from Session 0 and launches a worker into
the interactive session (CreateProcessAsUserW). That lets it capture the secure desktop (UAC
prompts, the lock screen) and keep streaming across reboots with nobody logged in — the same model
Sunshine and Apollo use. Service registration, firewall rules, and the supervisor all live in
punktfunk-host service install; the installer just lays the exe down and calls it elevated.
One core, Windows backends
Most of punktfunk is platform-agnostic. punktfunk-core (protocol, FEC, crypto, session, transport,
the C ABI), the QUIC control plane, the GameStream wire logic, the management API, and the per-frame
pipeline orchestration are all shared with the Linux host. The Windows host is a set of
#[cfg(windows)] backends behind the same traits the Linux host uses:
| Subsystem | Linux backend | Windows backend |
|---|---|---|
| Capture | xdg ScreenCast portal → PipeWire (dmabuf) | Windows.Graphics.Capture (+ Desktop Duplication for the secure desktop) → D3D11 texture; FP16/10-bit when the desktop is HDR |
| Virtual display | KWin / Mutter / Sway / gamescope | SudoVDA signed IDD — create a WxH@Hz monitor per session, capture it, tear it down |
| Encode | ffmpeg-next NVENC (CUDA hwframes) |
NVENC with a D3D11 device (--features nvenc); HEVC Main10 / BT.2020 PQ for HDR |
| Input — mouse/keyboard | libei / wlr protocols | SendInput (Win32 VK + absolute mouse) |
| Input — gamepads | uinput Xbox 360 pad + rumble | ViGEm virtual pad + rumble back-channel |
| Audio capture | PipeWire sink-monitor | WASAPI loopback |
| Virtual mic | PipeWire Audio/Source |
WASAPI virtual mic |
The virtual display uses SudoVDA (the Sunshine Virtual Display Adapter) — a pre-built, signed Indirect Display Driver — so there is no kernel driver to author or WHQL-sign. The installer bundles and stages it; if it's absent, the host falls back to capturing an existing monitor (losing the per-client native-resolution output).
Limitations
- NVIDIA-only. NVENC is the only encoder backend — there is no AMD / Intel / software encode path on Windows.
- x64-only. No ARM64 build (no ARM64 NVIDIA driver, and SudoVDA is x64-only).
- Newer than the Linux host. The Linux host is the most battle-tested path; the Windows host is more recent, with the virtual-mic and gamepad backends the youngest pieces.