The Linux native plane has been 8-bit for a reason that stopped being true: `capturer_supports_hdr()` returned a flat `false` because Mutter's virtual monitors are SDR-only upstream. That is still right for Mutter, KWin and wlroots — and wrong for gamescope, whose node can now offer 10-bit BT.2020 PQ (packaging/gamescope). Open the three gates that held it off, together: * the capture-side gate becomes SOURCE-AWARE (`capturer_supports_hdr_for`): Windows keeps its platform answer, gamescope asks whether the resolved binary offers the formats, everything else stays false. It must be truthful rather than optimistic — the Welcome is irrevocable, and PQ frames on an 8-bit encoder are a deliberate hard error — so every term is a static fact resolved before anything is spawned, including "do we spawn gamescope at all" (an attach inherits someone else's flags and can promise nothing); * `want_hdr` reaches the capturer: `open_virtual_output` grew the parameter it never had, and the host arm stopped dropping `want.hdr` on the floor; * the spawn gains `--hdr-enabled --hdr-debug-force-support` on all three sub-modes (bare args, the `GAMESCOPE_BIN` wrapper, the SteamOS PATH shim), from one shared `hdr_args` — the force flag is what makes it work headless, and forgetting it looks exactly like a negotiation failure. Two things that would have gone wrong quietly: * the keep-alive reuse key gains `hdr`. gamescope cannot turn HDR on live, so a kept SDR display handed to an HDR session would give the game no HDR surfaces while the stream negotiated PQ over an SDR composite — wrong, and not obviously broken. Same for the managed session-plus/SteamOS reuse check. * the HDR-negotiation-failure latch becomes PER SOURCE. It was one process-wide flag, so a monitor that left HDR mode would have disabled gamescope HDR until the host restarted, and vice versa — two facts with nothing in common but the word HDR. GameStream follows the same shape: `host_hdr_capable` gains the gamescope arm, and the RTSP gate's live BT.2100 monitor probe is scoped to the portal source — a headless box has no monitor to be in HDR mode, so running it there would hard-refuse every gamescope HDR session. Off by default for one release (`PUNKTFUNK_GAMESCOPE_HDR=1`), and `punktfunk-host hdr-probe` now answers for both Linux HDR sources.
punktfunk-host
The streaming host — the program you run on the machine whose desktop or games you want to stream. For each client that connects, it spins up a virtual display sized to that device, captures it on the GPU, encodes with hardware NVENC/VAAPI/AMF/QSV, and sends it out over a low-latency transport — no physical monitor, no letterboxing, no rearranging your real screens.
It speaks two protocols from one process:
- GameStream — so any Moonlight / Artemis client works day one.
punktfunk/1— punktfunk's own faster protocol (QUIC control plane, GF(2¹⁶) FEC + AES-GCM data plane) that the native clients use.
Runs on Linux (the primary, most battle-tested path) and Windows (x64). The shared protocol,
FEC, and crypto live in punktfunk-core; this crate is everything
platform-facing around it.
What it does
- Per-client virtual displays at the exact WxH@Hz. Linux uses per-compositor backends — KWin, gamescope, Mutter, and Sway/wlroots; Windows uses its own all-Rust IddCx virtual display, even on the secure desktop (UAC / lock screen).
- GPU zero-copy capture → encode. dmabuf → CUDA/Vulkan → NVENC on Linux; on Windows the host pushes frames straight into its own IDD (sealed IDD-push, no screen-scraping) → GPU encode. Encoders auto-select by GPU vendor: NVENC (NVIDIA), VAAPI (Linux AMD/Intel), AMF/QSV (Windows AMD/Intel), or software H.264 as a floor. HDR/10-bit and HEVC 4:4:4 supported.
- Input injection. Mouse/keyboard (libei / gamescope EIS / wlr / Windows SendInput) and virtual gamepads — Xbox 360/One, DualSense, DualShock 4 — with rumble and HID feedback back-channels.
- Audio both ways. Opus audio host→client, plus a virtual microphone the client can talk into.
- Trust & discovery. A persistent host identity, SPAKE2 PIN pairing (default) or TOFU, and mDNS auto-advertisement so clients find the host without typing an IP.
- Management API + web console. A REST API (
mgmt.rs, OpenAPI atapi/openapi.json) drives status, paired devices, and on-demand pairing; the browser UI is inweb/.
Run it
punktfunk-host serve runs inside your desktop session. Bare serve is the secure native-only
default (punktfunk/1 + the management API); add --gamestream on a trusted LAN to also accept
stock Moonlight clients.
# Linux, from the repo root (see the repo README "Running on this box" for the headless recipe):
cargo run -rp punktfunk-host -- serve # native-only (secure default)
cargo run -rp punktfunk-host -- serve --gamestream # + Moonlight compatibility
Then pair from the web console (https://<host-ip>:47992) or the client app.
Most people should install a package rather than run from source — see
packaging/ (apt · rpm/COPR/bootc · Arch/sysext · Windows installer) and
the per-platform guides at docs.punktfunk.unom.io/docs/install.
Subcommands
| Command | Purpose |
|---|---|
serve |
The host (native punktfunk/1 + mgmt API; --gamestream adds Moonlight). |
punktfunk1-host |
Standalone native-protocol listener for testing/measurement (--source virtual, --max-sessions). |
openapi |
Print the management-API OpenAPI spec (regenerates api/openapi.json). |
library |
Inspect the multi-store game library. |
service · driver · web |
Windows: SCM service, driver install, bundled web console. |
*-test / *-selftest / *-probe |
Diagnostics (input, zero-copy, HDR, compositor, gamepads). |
--help lists them all.
Layout
src/
main.rs CLI + subcommand dispatch
config.rs · session_plan.rs · session_tuning.rs · pipeline.rs session setup + the frame pipeline
vdisplay/ per-compositor virtual outputs (kwin · gamescope · mutter · wlroots)
capture/ · capture.rs screen/dmabuf capture (+ Windows IDD-push)
encode/ · encode.rs per-GPU encoders (nvenc · vaapi · ffmpeg_win (AMF/QSV) · sw)
linux/zerocopy/ dmabuf → CUDA → NVENC bridges (EGL/GL tiled, Vulkan LINEAR)
inject/ · inject.rs input backends (libei · wlr · uinput gamepads · UHID DualSense/DS4)
audio/ · audio.rs Opus out + virtual mic (PipeWire / WASAPI)
gamestream/ Moonlight compat: nvhttp · pairing · rtsp · control · stream · gamepad · apps
native.rs the native punktfunk/1 host (QUIC control + native-thread UDP data plane)
mgmt.rs · native_pairing.rs · stats_recorder.rs management API, pairing, perf capture
hdr.rs · library.rs HDR metadata; multi-store game library
linux/ · windows/ platform-confined backends
Related
punktfunk-core— the shared protocol · FEC · crypto core- Clients — the apps that connect (Apple · Linux · Windows · Android · probe)
- Packaging & docs — install & operate
- punktfunk-planning (internal planning repo) — architecture rationale and deep-dive plans