Ship the punktfunk Linux client to the Steam Deck as a Flatpak — the only viable
SteamOS install path, since /usr is read-only and lacks libadwaita/SDL3 — and
publish both it and the Decky plugin through Gitea. Built and validated live on a
Steam Deck (SteamOS 3.7): bundle installs user-scope, all libs resolve, libavcodec
resolves to the codecs-extra HEVC build, devices=all for DualSense hidraw.
packaging/flatpak (new):
- io.unom.Punktfunk.yml on GNOME 50 / freedesktop-sdk 25.08. rust-stable//25.08
(rustc 1.96 — the GTK4 chain needs >=1.92; the EOL GNOME-48/24.08 rust-stable at
1.89 could not build it) + llvm20 (libclang for bindgen in ffmpeg-sys-next/sdl3-sys).
HEVC libavcodec comes from the runtime's auto codecs-extra extension point (no
app-side codec declaration). Bundled SDL3 3.4.10 (matches sdl3-sys 0.6.6+SDL-3.4.10).
finish-args: wayland/fallback-x11, --device=all (GPU/VAAPI + evdev + hidraw — flatpak
cannot bind /dev/hidrawN char devices via --filesystem), pulseaudio, network,
~/.config/punktfunk.
- metainfo.xml, desktop, square SVG icon, build-flatpak.sh (offline cargo-sources;
on-Deck org.flatpak.Builder or CI), README.
clients/decky:
- add LICENSE (MIT), fix package.json license (BSD-3-Clause -> Apache-2.0 OR MIT),
add scripts/{package.sh,deploy.sh} (the plugins dir is root-owned: stage to /tmp,
sudo install, restart plugin_loader), align the launcher fallback to the real
flatpak app id io.unom.Punktfunk, rewrite the install section.
.gitea/workflows:
- flatpak.yml: privileged Fedora container builds the bundle and publishes to the
Gitea generic registry (+ release attachment on tags).
- decky.yml: pnpm build -> store-layout zip -> registry (stable latest/ URL for
Decky "install from URL").
docs: packaging/README + packaging/flatpak/README.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
punktfunk
A ground-up low-latency desktop streaming stack, built Linux-first, with a shared Rust protocol core and native clients per platform.
punktfunk is a placeholder codename. The bet: ship a Linux virtual-display streaming
host that speaks the existing Moonlight protocol (every Moonlight/Artemis client works
day one), then break the ~1 Gbps FEC wall with a GF(2¹⁶) Leopard-RS transport as a
negotiated extension. See docs/implementation-plan.md.
Status
| Milestone | State |
|---|---|
M1 — punktfunk-core + C ABI |
✅ done & hardened (FEC, packetization, AES-GCM, session, adversarial-review fixes, punktfunk_core.h) |
| M2 — GameStream host → stock Moonlight | ✅ live end-to-end: pairing, RTSP, audio, per-client virtual output at native res, GPU zero-copy NVENC, gamepads |
M3 — punktfunk/1 native protocol |
✅ validated live: QUIC control + GF(2¹⁶) FEC/AES data plane, SPAKE2 PIN pairing, mid-stream mode renegotiation |
| M4 — client decode + present (Apple) | 🟡 macOS first light: AnnexB→VideoToolbox HEVC on glass + input/pairing over punktfunk/1 (clients/apple); iOS + presenter next |
| Web console + management API | ✅ TanStack web console (web/) over the OpenAPI mgmt API: host status, paired devices, on-demand native pairing (arm → show PIN) |
The GameStream host works with a stock Moonlight client — validated live on NVIDIA
(RTX 5070 Ti & RTX 4090, driver 595): trust-on-first-use pairing that persists, an app
catalog, RTSP/ENet/audio, and video at the client's exact resolution and refresh via a
per-session virtual output (KWin, gamescope, Mutter, Sway backends), encoded with GPU
zero-copy (dmabuf → CUDA/Vulkan → NVENC) at up to 5120×1440@240. The native
punktfunk/1 protocol adds a QUIC control plane and a GF(2¹⁶) Leopard-FEC + AES-GCM data
plane (p50 ~0.8 ms capture→reassembled at 720p120), with a SPAKE2 PIN pairing ceremony. Both
run from one process (serve --native), managed through a REST API + web console. Builds
against FFmpeg 7 or 8; deployed live on Bazzite. Full status: CLAUDE.md;
roadmap, setup guides & progress: the docs site (docs-site/ — Fumadocs;
bun run dev), with the canonical roadmap and
status there. Design notes stay in docs/.
Layout
crates/
punktfunk-core/ protocol · FEC · pacing · crypto · quic — the C ABI (lib + cdylib + staticlib)
punktfunk-host/ Linux host: vdisplay · capture · encode · inject · gamestream · m3 · mgmt · native_pairing
punktfunk-client-rs/ punktfunk/1 reference client (M3 headless; M4 adds decode+present)
clients/{apple,android}/ native client scaffolds (import punktfunk_core.h); apple = macOS first light
web/ TanStack web console (host status · paired devices · pairing) over the mgmt API
packaging/ Fedora/Bazzite RPM · bootc image · COPR (see packaging/bazzite/README.md)
include/punktfunk_core.h cbindgen-generated C header (checked in)
tools/{latency-probe,loss-harness}/ measurement (plan §10)
docs/{implementation-plan,roadmap,windows-host,dualsense-haptics}.md
Build & test
cargo build --workspace # green on Linux and macOS
cargo test --workspace # unit + loopback + proptest + C ABI harness
cargo clippy --workspace --all-targets
cargo run -p loss-harness # FEC loss-resilience sweep (no network needed)
bash crates/punktfunk-core/tests/c/run.sh # standalone C-ABI link+round-trip proof
The C header regenerates from crates/punktfunk-core/src/abi.rs on every build (cbindgen via
build.rs) into include/punktfunk_core.h.
Design invariants
- One core, linked everywhere. Protocol/FEC/crypto/pacing live in
punktfunk-coreexactly once, exposed over a stable, versioned C ABI (punktfunk_abi_version(),PunktfunkConfigcarries its ownstruct_size). - No async on the hot path. The per-frame pipeline uses native threads only;
tokio/quinnare gated behind the off-by-defaultquicfeature (control plane only). - FEC is the wall-breaker. GF(2⁸) (≤255 shards/block) for Moonlight compat; GF(2¹⁶) (≤65535 shards/block, SIMD, O(n log n)) to push past ~1 Gbps.
License
MIT OR Apache-2.0.