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G8's Android half, and the last of the three clients. Same failure as the other two: a controller with a gyro, in a session whose virtual pad has no motion plane, does nothing when tilted — silently, with no way from the couch to tell that apart from a broken sensor. The fix is the Controller type setting, so the notice names it. Android read neither the requested nor the resolved backend, so this needed a plumb. What it did NOT need was a third copy of the rule. `nativePadMotionReaches` takes the kind a pad declared and answers off `pad_motion_reaches` in punktfunk-core, where the argument and the tests already live. The rule is subtler than it looks — the host builds each pad from its OWN declaration and folds what it cannot build, so neither the declaration nor the session echo answers it alone — and every way of getting it wrong is silent. A Kotlin transcription would have been a third thing to keep in step with the host, which is exactly how the SDL half got it wrong the first time. Asked once per pad, at claim, in `openExternal` — where the pad's kind is already being declared to the host — and the answer held for the pad's lifetime on the `ExternalPad`. Not per sample: this runs at a DualSense's full report rate. `hasGyro` gates only the NOTICE, and defaults to false. `DsCapture` passes true — every pad it captures is a Sony one whose IMU is a headline feature, forwarded on the rich plane. `Sc2Capture` keeps the default, because the Steam Controller 2's motion rides inside the opaque passthrough report that `hidReport` carries, which nothing here may second-guess: warning about motion for a pad that never calls `motion()` would be a notice about a feature the player never lost. The suppression itself is on `motion()` regardless, where it costs a dead pad nothing and stops a live one paying to send samples the host will decode and discard. The notice sits at the BOTTOM of the stream overlay, unlike the mic-chord confirmation at the top. The two can coincide — a pad is claimed at roughly the moment someone might be muting — and one landing on the other would cost the user both. It holds 6 s rather than the mic chord's 1.6: that one confirms something the user just did, this one explains something they did not, in a sentence they have to read. Nulled at teardown beside `onExitArmed`/`onMicChord`, for the same reason those are — a slot closing during release must not poke Compose state on the way out. Not covered by tests, and this is a limit of the module rather than a choice: `GamepadRouter` needs Android plus a live JNI handle, there is no Robolectric here, and the predicate it defers to is pure Rust that already has its table. So the parts that carry the reasoning are argued in comments, as `DsCapture`'s claim/teardown ordering already is. What IS mechanically verified is the piece that a compiler cannot catch and a device would fail on: the JNI symbol `Java_io_unom_punktfunk_kit_NativeBridge_nativePadMotionReaches` is present and global in the built arm64-v8a `.so`, so the `external fun` resolves rather than throwing `UnsatisfiedLinkError` at the first pad. Gate: `:kit:compileDebugKotlin`, `:kit:testDebugUnitTest` (62 cases, 0 failed, read out of the JUnit XML rather than inferred from a green build — unchanged from this branch's previous count), `:app:compileDebugKotlin` and `:app:testDebugUnitTest` (67 cases, 0 failed), with `:kit:cargoNdkRelease` rebuilding the JNI crate clean across all three ABIs, plus `cargo fmt --check` on it. On-glass verification is owed on the rig the earlier legs used, and is worth doing as one pass with the two already owed there.
Low-latency desktop and game streaming with first-class Linux and Windows hosts.
Run the host on a Linux machine or a Windows PC, connect from a Mac, PC, phone, tablet, or TV, and stream your desktop or games — each device at its own native resolution and refresh rate, over your local network.
📖 Documentation: docs.punktfunk.unom.io — start with How It Works or the Quick Start.
💬 Community: Discord — chat, support, and Android beta access · r/Punktfunk.
🔒 Security: found a vulnerability? Report it privately to security@punktfunk.com — see SECURITY.md. Please don't open a public issue.
Punktfunk pairs a virtual-display streaming host with native clients on every platform. It speaks
the existing GameStream protocol, so any Moonlight client works
day one — and adds its own faster punktfunk/1 protocol that breaks the ~1 Gbps FEC wall with a
GF(2¹⁶) Leopard-RS transport. A single shared Rust core (punktfunk-core) holds the
protocol, FEC, and crypto, linked into the host and every native client — directly as a Rust crate
on Linux and Windows, and over a stable C ABI from the Apple and Android apps.
What makes it different
- Your device's exact mode. For each client that connects, the host spins up a virtual display sized to that device — 1080p60 to a laptop, 1440p120 to a desktop, 4K to a TV, all at once. No letterboxing, no scaling, no rearranging your real monitors.
- Displays you configure, not just create. Keep a game's display (and the game) alive across disconnects so a reconnect drops straight back in; make the stream your sole desktop or extend alongside your monitors; let several devices become monitors of one desktop; keep each client's scaling. One-click presets in the console — a dedicated couch box, a shared desktop, a multi-monitor workstation. See Virtual displays.
- A real virtual display on Windows, too. On Linux the host uses per-compositor virtual outputs; on Windows you get the same on-the-fly virtual display — at the client's exact mode, no physical monitor or dummy HDMI plug, even on the secure desktop (UAC / lock screen). It also has its own indirect display driver (IDD) the host pushes finished frames straight into, rather than scraping a screen — tight, push-based integration that's unusual for a Windows streaming host.
- Low latency, GPU end to end. Frames go straight from the compositor to the NVENC encoder with zero CPU copies (dmabuf → CUDA/Vulkan → NVENC), over a transport tuned for responsiveness rather than throughput. Stable 240 fps at 5120×1440; sub-millisecond capture-to-reassembly on-box, ~1.3 ms cross-machine on a LAN. (On Linux AMD/Intel, Vulkan Video for HEVC and AV1 with VAAPI for H.264 and as the fallback; a GPU-less software H.264 encoder exists as a last resort.)
- A library that fills itself. Steam and non-Steam titles show up as a grid on every client, and
plugins add their own sources — ROM Manager (your ROM collection, matched to installed emulators),
Playnite, VirtualHere. Install them from the console's Plugins page or with
punktfunk-host plugins add. See Plugins. - Works with what you already have. Any Moonlight/Artemis client connects over GameStream — and
native apps for macOS, Linux, Windows, and Android use the lower-latency
punktfunk/1protocol. - Secure by default. Hosts require a one-time SPAKE2 PIN pairing; after that, devices reconnect on a pinned identity. No accounts, no cloud. Hosts auto-advertise over mDNS, so clients find them on the network without typing an IP.
Status
| Component | State |
|---|---|
Core — punktfunk-core + C ABI (protocol · FEC · crypto · QUIC) |
✅ Complete & hardened |
| GameStream host → stock Moonlight | ✅ Live end-to-end: pairing, RTSP, audio, per-client virtual output at native resolution, GPU zero-copy NVENC, gamepads |
Native protocol — punktfunk/1 |
✅ Validated live: QUIC control + GF(2¹⁶) FEC/AES-GCM data plane, PIN pairing, mDNS discovery, mid-stream mode renegotiation |
| Windows host (Windows 11 22H2+, x64) | ✅ Beta — shipping as a signed installer: its own all-Rust IddCx virtual display (secure-desktop capable) with a sealed IDD-push capture path — finished frames pushed straight into its own driver, not screen-scraped (no DDA/WGC) · GPU encode (NVENC on NVIDIA, AMF/QSV on AMD/Intel, software H.264 without a GPU) · WASAPI audio · bundled virtual-gamepad drivers (no ViGEmBus) · HDR incl. Vulkan-game HDR. NVIDIA live-validated; AMD/Intel CI-green |
macOS / iOS / tvOS client (clients/apple) |
✅ Streaming live: VideoToolbox decode (HEVC, and AV1 on hardware that decodes it), controllers incl. DualSense, discovery, pairing, speed test |
Linux client (clients/linux + clients/session) |
✅ Streaming live: relm4/GTK4 launcher shell that spawns a Vulkan session binary — Vulkan Video / VAAPI / software decode, PipeWire audio, SDL3 controllers, Skia console UI; ships as Flatpak/apt/rpm/Arch |
Android client (clients/android, phone + TV) |
✅ Streaming live: AMediaCodec decode + HDR10, AAudio audio, controllers, discovery, pairing |
Windows client (clients/windows, WinUI 3) |
✅ Streaming live: WinUI 3 shell + Vulkan session presenter, hardware decode on all GPU vendors via Vulkan Video → D3D11VA → software (NVIDIA + Intel validated on glass), WASAPI audio, SDL3 controllers, discovery, pairing; ships as signed MSIX (x64 + ARM64). Hardware decode and HDR10 present validated on glass on NVIDIA and Intel, including HDR pass-through on the Intel D3D11VA path |
Web console + management API (web/) |
✅ TanStack console over the OpenAPI mgmt API: host status, paired devices, on-demand PIN pairing, game library, virtual-display presets, plugin store, GPU selection, performance capture graphs, live host logs, host updates |
Every native client also ships a tiered stats overlay (Compact / Normal / Detailed) with a
shared vocabulary across platforms, and the session client carries a full gamepad-driven console
shell (pf-console-ui): host list, PIN pairing, settings, and an on-screen keyboard.
The GameStream host works with a stock Moonlight client — validated live on NVIDIA hardware
(RTX 5070 Ti, RTX 4090): PIN pairing that persists across restarts, an app catalog, RTSP/ENet/audio,
and video at the client's exact resolution and refresh via a per-session virtual output (KWin,
gamescope, Mutter, and Sway/wlroots backends), encoded with GPU zero-copy (dmabuf → CUDA/Vulkan →
NVENC) up to 5120×1440@240. The native punktfunk/1 protocol adds a QUIC control plane and a
GF(2¹⁶) Leopard-FEC + AES-GCM data plane (p50 ~0.8 ms capture→received at 720p120), with
mid-stream mode renegotiation and a wall-clock skew handshake so latency stays valid across machines.
Both run from one process: bare punktfunk-host serve is the secure native-only default
(punktfunk/1 + the management API/web console), and serve --gamestream additionally enables the
GameStream/Moonlight-compat planes (opt-in, trusted-LAN only — GameStream has inherent on-path
weaknesses). The host is managed through a REST API and web console. The host builds against
FFmpeg 7 or 8; the clients link no FFmpeg at all — they decode natively (Vulkan Video, DXVA,
VAAPI, VideoToolbox, MediaCodec, openh264 + rav1d).
What works where: the support matrix · where it's heading: the roadmap.
Install the host
Pick your platform and install from its package registry — the per-platform guide covers adding the repo, first run, and the web console. The Linux host is the primary, most battle-tested path; on SteamOS the host is built on-device by a script instead, and a Windows host ships as a signed installer (all-vendor: NVIDIA, AMD, Intel).
| Platform | Install | Guide |
|---|---|---|
| Ubuntu / Debian (apt) | sudo apt install punktfunk-host (after adding the repo) |
Ubuntu / Debian · packaging/debian |
| Bazzite / Fedora Atomic (systemd-sysext) | curl -fsSLO https://git.unom.io/unom/punktfunk/raw/branch/main/packaging/bazzite/punktfunk-sysext.sh && sudo bash punktfunk-sysext.sh install (no layering, no reboot; rpm-ostree + bootc also supported) |
Bazzite |
| Fedora (dnf) | sudo dnf install punktfunk (after adding the repo; the console comes with it) |
Fedora · packaging/rpm |
| Arch / CachyOS (pacman) | sudo pacman -Syu punktfunk-host (binary repo — always a full -Syu) |
Arch Linux · packaging/arch |
| SteamOS / Steam Deck (on-device build) | bash ~/punktfunk/scripts/steamdeck/install.sh (after cloning this repo to ~/punktfunk) |
SteamOS (Host) |
| Windows (11 22H2+, x64) | winget install unom.PunktfunkHost (after winget source add -n punktfunk https://winget.punktfunk.unom.io -t Microsoft.Rest) · or the signed setup.exe from the package registry |
Windows Host · packaging/winget |
punktfunk-host is the streaming host; punktfunk-web is the browser console (pairing + status).
Linux: every package ships systemd user units, so you don't launch the host by hand. The
host unit won't start until ~/.config/punktfunk/host.env exists, so copy the template your package
installed first:
mkdir -p ~/.config/punktfunk
# /usr/share/punktfunk/ on Fedora/Arch/Bazzite, /usr/share/punktfunk-host/ on Debian/Ubuntu
# (on Bazzite take host.env.bazzite instead)
cp /usr/share/punktfunk/host.env.example ~/.config/punktfunk/host.env
systemctl --user enable --now punktfunk-host # the streaming host
systemctl --user enable --now punktfunk-web # the web console (Arch: install punktfunk-web first)
The shipped host unit runs serve --gamestream — the native punktfunk/1 plane plus the
GameStream/Moonlight-compat planes, which belong on a trusted LAN only; for a native-only host drop
the flag with a systemctl --user edit punktfunk-host drop-in (which needs an empty ExecStart=
line before the replacement — the install guide has the snippet). Then open
https://<host-ip>:47992 and pair.
How the virtual display and input are wired up depends on your desktop — see KDE · GNOME · Steam / gamescope · Sway.
Windows: the installer registers and starts the host as a LocalSystem service, so there is
nothing to run by hand — open the web console and pair. Use
punktfunk-host service start|stop|restart|status if you need to control it. Upgrades happen in
place — the console's Updates card, winget upgrade unom.PunktfunkHost, or the newer
setup.exe over the old install; uninstall from Add/Remove Programs.
Full instructions: docs.punktfunk.unom.io/docs/install.
The console's Host page also shows when a newer host is out, along with the exact command for how this box was installed (or a one-click Update now on Windows) — see Updating the host. To remove it again, or to go back to an earlier version, see Uninstalling and Release Channels.
Connect a client
| Streaming to… | Use |
|---|---|
| Mac, iPhone, iPad, Apple TV | The Apple app (clients/apple) — also on TestFlight |
| Linux desktop / laptop | punktfunk-client (Flatpak / apt / rpm / Arch) |
| Steam Deck | The Decky plugin in Gaming Mode — it launches the client for you (Steam Deck); in Desktop Mode, the Flatpak directly |
| Android phone or TV | The Android app (clients/android) |
| Windows | Native punktfunk-client (signed MSIX) or Moonlight |
| Scripts, automation, another launcher | punktfunk — the headless CLI shipped in the Linux client packages (punktfunk pair, punktfunk hosts list --json, punktfunk launch <host>) |
| Anything else (browser, old phone, smart TV) | Moonlight over GameStream |
Each client discovers hosts on the network automatically and does a one-time PIN pairing. Per-device install steps: /docs/install-client.
Build & test (from source)
For development, or as an install fallback where no package is available:
cargo build --workspace # core, host, tray, shared client crates, Linux shell + session client, the `punktfunk` CLI, probe (Linux & macOS)
cargo test --workspace # unit + loopback + proptest + C ABI harness
cargo clippy --workspace --all-targets -- -D warnings
cargo fmt --all --check
cargo run -p loss-harness # FEC loss-resilience sweep (no network needed)
bash crates/punktfunk-core/tests/c/run.sh # standalone C-ABI link + round-trip proof
The C header regenerates from crates/punktfunk-core/src/abi.rs on every build (cbindgen via
build.rs) into include/punktfunk_core.h. The Apple, Android, and Windows clients have their own
toolchains (Xcode/swift build, Gradle, and cargo on the MSVC target) — see each client's README
and the docs site.
Layout
crates/
punktfunk-core/ protocol · FEC · pacing · crypto · QUIC control plane — the C ABI (lib + cdylib + staticlib)
punktfunk-host/ the host (Linux + Windows): virtual displays · capture · encode · input · GameStream · punktfunk/1 · mgmt
pf-client-core/ shared client plumbing (Linux + Windows): session pump · native decode ladder · audio · SDL3 gamepads · trust · discovery
pf-presenter/ Vulkan session presenter: SDL3 window · ash swapchain · frame present · input capture
pf-console-ui/ Skia console UI for the session client: gamepad shell · stats OSD · pairing · on-screen keyboard
pf-bitstream/ H.264 / H.265 / AV1 bitstream parsing + per-AU decode plans — the one parser every native rung submits from
pf-vkdecode/ native Vulkan Video decode (H.264 / H.265 / AV1) on the presenter's own device
pf-dxvadec/ native DXVA buffer layouts + AuPlan → picparams conversion (the Windows D3D11VA rung)
pf-vaadec/ native libva buffer layouts + AuPlan → picparams conversion (the Linux VAAPI rung)
pf-driver-proto/ host ↔ pf-vdisplay driver contract: control IOCTLs + IDD-push frame transport (no_std)
punktfunk-tray/ host tray icon (Windows notification area / Linux StatusNotifierItem)
clients/
apple/ macOS / iOS / tvOS app (Swift · VideoToolbox · Metal · GameController)
linux/ Linux launcher shell (Rust · relm4 / GTK4 / libadwaita) — spawns the session client to stream
session/ punktfunk-session, the Vulkan streaming session (Rust · SDL3 · ash · Skia console UI) — also runs standalone (gamescope, Decky)
windows/ Windows desktop app (Rust · WinUI 3 · D3D11 · WASAPI · SDL3)
android/ Android phone + TV app (Kotlin · Rust JNI core · AMediaCodec · AAudio)
cli/ punktfunk, the headless client CLI — pair · hosts · wake · library · launch · punktfunk:// links
probe/ headless reference / measurement client for punktfunk/1
decky/ Steam Deck Decky plugin
web/ web console (TanStack) over the management API — status · devices · pairing · library · displays · plugins · GPUs · performance · logs · updates
api/openapi.json management-API OpenAPI spec (regenerated via `punktfunk-host openapi`, checked in)
sdk/ `@punktfunk/host` — TypeScript management-API client + event stream (Effect)
plugin-kit/ `@punktfunk/plugin-kit` — the plugin authoring kit (bun / TypeScript)
packaging/ apt · rpm / COPR · Arch · Flatpak · Bazzite sysext + bootc · Windows installer + drivers · winget · Nix · gamescope
docs-site/ public documentation site (Fumadocs) — https://docs.punktfunk.unom.io
include/punktfunk_core.h cbindgen-generated C header (checked in)
tools/ latency-probe · loss-harness (measurement)
ci/ CI container images (rust-ci · fedora-rpm)
Design invariants
- One core, linked everywhere. Protocol, FEC, and crypto live in
punktfunk-coreexactly once, exposed over a stable, versioned C ABI (punktfunk_abi_version(),PunktfunkConfigcarries its ownstruct_size). Every native client links the same core. - No async on the hot path. The per-frame pipeline uses native threads only;
tokio/quinnare gated behind the off-by-defaultquicfeature (control plane only). - Native client resolution, no scaling. Each session gets a virtual output at exactly the
client's WxH@Hz; each compositor keeps its own backend behind a shared
VirtualDisplaytrait. - FEC is the wall-breaker. GF(2⁸) (≤255 shards/block) for Moonlight compatibility; GF(2¹⁶)
(≤65535 shards/block, SIMD, O(n log n)) for
punktfunk/1to push past ~1 Gbps.
License
Licensed under either of
- Apache License, Version 2.0 (LICENSE-APACHE or https://www.apache.org/licenses/LICENSE-2.0)
- MIT license (LICENSE-MIT or https://opensource.org/licenses/MIT)
at your option — SPDX-License-Identifier: MIT OR Apache-2.0.
Contribution
Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions. See CONTRIBUTING.md.
Third-party components
Punktfunk's own source is MIT/Apache-2.0. Shipped binaries additionally link third-party components
under their own (permissive) licenses — see THIRD-PARTY-NOTICES.txt
(regenerate with scripts/gen-third-party-notices.sh). The Windows host build also
bundles FFmpeg under the LGPL v2.1+ (dynamically linked, replaceable DLLs; the license text and
notice ship in the installed licenses/ folder). The clients bundle no FFmpeg — they link
none.
Trademarks
Punktfunk is an independent project and is not affiliated with, endorsed by, or sponsored by NVIDIA, Microsoft, Sony, Valve, or the Moonlight project. "GameStream", "Moonlight", "Xbox", "DualSense", "DualShock", and "PlayStation" are trademarks of their respective owners and are used here only to describe interoperability.