The Windows console's "Streamed screen" picker SAVED and then did nothing. `capture_monitor` is
platform-neutral, so the PUT persisted; every consumer of it is Linux-gated, so a virtual display
was still created on connect. The operator got a control that acknowledged the click and changed
nothing — the worst of the three possible behaviours.
The root cause is not a missing gate, it is a missing BACKEND. Per-monitor capture is Linux/portal
only: `vdisplay::open`'s mirror arm is `#[cfg(target_os = "linux")]` because `pf-capture` has no
Windows entry point that can capture an arbitrary head. Its sole Windows entry point is
`open_idd_push`, a frame channel pushed by our OWN IddCx virtual display; DXGI Desktop Duplication
was deliberately REMOVED (`windows/dxgi.rs` keeps the GPU-preference hook only to stop DXGI
reparenting the virtual display off the pinned adapter, and says so). So there is nothing for a pin
to aim at, and exposing the picker got ahead of that.
Decision of record (user, this session): mark it unsupported now rather than build the Windows
backend here. A Windows mirror backend is a real feature gap and a project of its own — it needs a
duplication capturer plus everything the IDD-push path carries today (cursor sidechannel, 444,
10-bit, PyroWave, HDR) re-plumbed through it — not a follow-on to an enumeration commit.
Three places, so the answer is consistent wherever it is asked:
* `MonitorsResponse.pin_supported` — a CAPABILITY, reported by the build that would have to honor
the pin rather than sniffed from the OS client-side. When a Windows mirror backend lands this
flips and the console needs no change. `pinned` stays `None` off-Linux deliberately, and now says
why: it is what the console highlights as "sessions stream this", and highlighting a head nothing
will capture is the same lie in a different place.
* `enforced` drops `capture_monitor` off Linux. That list is exactly the "which controls are live vs.
coming soon" contract, and claiming this one unconditionally is what let the picker ship enabled.
* The PUT drops a non-Linux `capture_monitor` instead of storing it, and logs that it did. COERCED,
not rejected with a 400: this PUT is WHOLE-OBJECT, so a host that already stored a pin would have
every later settings save rejected over a field the operator cannot see — taking the other axes
down with it. This way such a policy self-heals on the next write.
Console: the picker renders read-only with an explanation, reusing the `envLocked` shape rather than
inventing a second one (`locked = envLocked || !pinSupported`). Managed heads were ALREADY excluded
from selection here (`mon.enabled && !mon.managed`), which is the "grey out, never filter blindly"
rule working as intended — the heads stay listed and explicable. `pin_supported` defaults to TRUE
when absent so an older host, which only ever shipped this picker where it worked, is not
retroactively locked out.
⚠️ `api/openapi.json` is hand-patched — punktfunk-host does not build on macOS, so the spec could not
be regenerated from the binary. The shape was verified by running the real generator over it: orval
emits `pin_supported: boolean` (required, no `?`) on `MonitorsResponse`.
Verified: `bun run codegen` (orval + paraglide + i18n parity: 434 messages, en + de), `bun run build`,
`bun run lint` (tsc --noEmit) all clean. Rust verified separately on .173 — see the next commit's
note if that lands, since neither xcheck target covers punktfunk-host.
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