The named next step after WP3's first increment. That increment deliberately REFUSED to arbitrate HEVC-with-sub-frame -- the fleet default, and the reported field case -- because engaging split there gives up sub-frame readback, whose whole value is that the send overlaps the encode. An encoder measuring only encode time would see split as ~2x faster, take it, and make end-to-end latency worse while reporting a win. This supplies the missing number. The real comparison is encode_1eng + send_of_last_slice against encode_2eng + send_of_whole_AU, so the challenger owes roughly spread x (slices-1)/slices. Split across the two sides that can each see half: - Host: new `Encoder::set_send_spread_us` (defaulted, forwarded by TrackedEncoder -- same trap class as set_wire_chunking, and unforwarded it would fail SILENTLY IN THE SAFE DIRECTION, which is the hardest kind to notice). The send thread is the only place a paced send is observed and the encode loop the only place the encoder can be touched, so it goes over an AtomicU32 like encoder_ceiling_kbps, EWMA-smoothed 3:1 per completed AU: one content spike must not flip a verdict that then gets cached. - Encoder: turns the raw spread into the handicap, because only it knows `slices`. SplitArbiter::with_handicap charges it to the challenger before the comparison. A unit test runs identical encode numbers with a cheap and an expensive send and asserts the verdict REVERSES -- with an expensive send the arm that looks twice as fast is a loss end to end, and the incumbent must hold. That is precisely the regression an encode-only arbiter ships. Gate now opens for HEVC+sub-frame only when a spread has actually been reported (and slices >= 2); with no hint it still refuses, so behaviour is unchanged until the host feeds it. Two mechanics this needed: - apply_split_mode became a PAIR flip (split + sub-frame), routed through resolve_split_subframe and restoring from `subframe_opened_with` so a session that never had sub-frame can never gain it. It also recomputes `subframe_chunks`, which reconfigure_bitrate does NOT -- spike S1c's finding; leave it stale and supports_chunked_poll keeps saying yes while numSlices never advances, so poll_chunk busy-polls its whole budget every AU. - The arbiter is now fed from BOTH completion points. A sub-frame session finishes through poll_chunk, so the incumbent arm of an HEVC experiment would otherwise never deliver a sample -- only the challenger, with sub-frame dropped, comes through poll. Verified .21: clippy -D warnings clean for pf-encode AND punktfunk-host with nvenc, 63 unit tests (1 new), 23/23 NVENC on-hardware green. Verified .133: Windows clippy -D warnings clean, zero dead_code. fmt clean.
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