enricobuehler
b8a33e21a2
First step of 1 Gbps+ readiness (the whole point of the GF(2^16) Leopard FEC): make 1 Gbps configurable and its dominant failure mode observable, before the real transport work (sendmmsg + paced encode|send split) lands. Investigation (6-way) verdict: we're ~halfway, and it's mostly clamps plus one real piece of work. The integer/type path, FEC (a 1 Gbps frame is only a few hundred shards in one GF(2^16) block, far under the 65535 ceiling), AES-GCM (AES-NI, ~10-25x headroom), and the M1 reassembler bounds (fully derived from the negotiated FecConfig) are ALL already 1 Gbps-ready and untouched. This commit (the configurable + observable foundation): - m3.rs: MAX_BITRATE_KBPS 500_000 -> 2_000_000 (2 Gbps headroom over the 1 Gbps+ target); MAX_PROBE_KBPS 1_000_000 -> 3_000_000 (probe can demonstrate headroom ABOVE the session cap so a client can confidently pick a 1 Gbps+ bitrate). - transport/udp.rs: TARGET_SOCKBUF 8 MB -> 32 MB (a multi-MB IDR keyframe burst no longer fills the buffer); scripts/99-punktfunk-net.conf bumped to match. - Observability: Transport::send now returns Ok(true|false) (false = WouldBlock send-buffer drop, previously a silent Ok(())). Session counts these as a new `packets_send_dropped` stat (distinct from recv-side packets_dropped) — in Stats, the C ABI PunktfunkStats (header regenerated), a PUNKTFUNK_PERF periodic wire-Mbps + drop dump in virtual_stream, and the speed-test probe completion log. This is the dominant 1 Gbps+ loss mode and was invisible. Loopback-verified: a probe now runs at 1.2 Gbps target (no longer truncated to 1 Gbps) with the drop counter live. NOT yet a sustained-1-Gbps proof — the single-send()-per-packet native path is the next, real piece of work (port the proven GameStream sendmmsg + paced send thread into the core Transport). 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: docs/roadmap.md.
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.