Files
punktfunk/crates/punktfunk-host
enricobuehler 06d594bc2a fix(host): encode-stall watchdog — heal the silent AMF/QSV freeze in place
Field reports: Windows AMD/Intel streams freeze after ~3-5 min regardless of
desktop activity. Root cause: the libavcodec AMF/QSV poll is non-blocking
(EAGAIN -> Ok(None)), and the encode loop's drain treated None as benign
without popping `inflight` — a wedged driver (QueryOutput stops producing)
meant frames kept being submitted, inflight grew unboundedly, no AU ever
reached the send thread, and nothing logged: a silent permanent freeze. The
input-side twin: once libavcodec's one-frame buffer fills, avcodec_send_frame
EAGAINs and the submit `?` killed the whole session.

Add `Encoder::reset()` (in-place encoder rebuild; implemented for AMF/QSV by
dropping the wedged libavcodec encoder so the next submit re-opens it on the
current device, forced IDR) and an encode-stall watchdog in the stream loop:
trip on a poll error, on no AU within max(2 s, 8 frame intervals) while frames
are owed, or on an owed backlog worth more than the window's frames (the
slow-leak latency-runaway form). Recovery is a bounded (5 consecutive, cleared
by any delivered AU) in-place rebuild + forced IDR — a logged ~one-second
hiccup instead of a dead stream; exhaustion or a reset-less backend still
fails the session with a clear error. Submit failures route through the same
bounded recovery. The three existing pipeline-rebuild paths (session switch,
mode switch, capture loss) now also clear the stale in-flight records that
pointed at the dropped encoder.

Backends whose poll blocks (direct NVENC sync, software) can't false-trip:
they never return Ok(None) mid-stream and drain inflight below depth each
tick. Validated: clippy -D warnings (nvenc,amf-qsv), 191 host tests, synthetic
E2E 300/300 frames, and an on-glass AMD iGPU session (1080p120 HDR hevc_amf).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
2026-07-06 14:36:29 +02:00
..

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 at api/openapi.json) drives status, paired devices, and on-demand pairing; the browser UI is in web/.

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)
  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
  • punktfunk-core — the shared protocol · FEC · crypto core
  • Clients — the apps that connect (Apple · Linux · Windows · Android · probe)
  • Packaging & docs — install & operate
  • design/ — architecture rationale and deep-dive plans