2026-07-12 review of the host encoders / client decoders / RFI plane. NVENC (both), AMF-LTR, the session glue, and the client RfiTracker came out clean; every fix lands in the Vulkan Video backend + dispatch: 1. HEVC: author each P-frame's short-term RPS to retain ALL resident DPB pictures (minus the setup slot), not just its one reference. HEVC 8.3.2 evicts unlisted pictures, and clients keep FEEDING the decoder while frozen — so with the old single-pic RPS, a conforming parser (FFmpeg = the Linux VAAPI/Vulkan and Windows D3D11VA clients) had already discarded the picture an RFI recovery anchor references whenever a fed post-loss frame preceded it: generate_missing_ref, and the "clean" anchor plus everything chained after it decodes as garbage. Pure builder (`build_h265_rps_s0`) + unit tests; AV1 needs nothing (slot-based retention). The smoke test now encodes a fed post-loss frame between loss@4 and anchor@6 so an ffmpeg decode of the dropped dump exercises exactly this (expect ONE POC-4 complaint, never POC 3) — revalidate on the AMD box; this NVIDIA dev box fails the backend earlier at HEVC header retrieval (pre-existing). 2. AV1: chain PhysicalDeviceVideoEncodeAV1FeaturesKHR (videoEncodeAV1 = TRUE, stype 1000513004) into device creation — spec-required for the ENCODE_AV1 codec op; RADV tolerated the omission, validation layers and stricter drivers do not. 3. RFI decline no longer self-arms force_kf — that bypassed the session glue's 750 ms IDR cooldown, turning a storm of hopeless RFI requests into one full IDR each. Decline like NVENC/AMF and let the caller's coalesced keyframe path own the fallback; add the missing first>last guard for parity. 4. open_video_backend now returns the label of the branch that ACTUALLY opened, so the mgmt API / web console reports "vulkan" instead of "vaapi" for the default-on Vulkan sessions (the old dispatch-mirror resolved_backend_label went stale when the backend gained its VAAPI fallback; deleted). Structure: the ~230-line inline HEVC coding block moves to record_coding_h265 (symmetric with record_coding_av1) and the duplicated pre-encode barriers dedupe into begin_encode_cmd. Follow-up plan (separate, punktfunk-planning): bring the post-loss freeze + RECOVERY_ANCHOR/POINT lift to the Android/Windows/Apple clients via a shared ReanchorGate (design/client-reanchor-freeze-parity.md). Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
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
punktfunk1.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