enricobuehler ab6dda2e5f feat: M0 capture→encode pipeline + M2 GameStream host (pairing, RTSP, video)
M0 (lumen-host) — verified on NVIDIA RTX 5070 Ti / Ubuntu 25.10:
headless wlroots → xdg ScreenCast portal → PipeWire → NVENC HEVC → playable file,
with each access unit round-tripped through a lumen_core host↔client Session
(FEC + packetize + reassemble), 0 mismatches.
- capture.rs: SyntheticCapturer + portal capture (ashpd 0.13 + pipewire 0.9), format-aware
- encode/linux.rs: NVENC via ffmpeg-next 7 (BGRx/RGB → rgb0, no host-side swscale)
- m0.rs: capture→encode→file + lumen-core loopback verification

M2 P1 (lumen-host gamestream/) — a stock Moonlight client pairs + launches, verified live:
- mDNS _nvstream._tcp + nvhttp /serverinfo (HTTP 47989, mutual-TLS HTTPS 47984)
- 4-phase pairing: PIN→AES-128-ECB / SHA-256 / RSA-PKCS1v15 / X.509, custom rustls
  ClientCertVerifier for the mutual-TLS pairchallenge
- /applist, /launch (rikey/rikeyid/mode), hand-rolled RTSP (OPTIONS/DESCRIBE/SETUP×3/
  ANNOUNCE/PLAY, one-request-per-TCP-connection per moonlight-common-c's read-to-EOF)
- video.rs: GameStream RTP + NV_VIDEO_PACKET wire packetizer, data-shards-only (0% FEC,
  clean-LAN), unit-tested (single/multi-block)

Docs: docs/m2-plan.md (phased plan) + docs/research/ (ground-truth protocol spec).
Bootstrap/setup updated for the verified path (libnvidia-gl, render/video groups, GPU
EGL, pipewire 0.9). Workspace clippy-clean, tests green.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
2026-06-09 07:14:59 +00:00

lumen

A ground-up low-latency desktop streaming stack, built Linux-first, with a shared Rust protocol core and native clients per platform.

lumen 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 — lumen-core + C ABI done & tested (FEC, packetization, crypto, session, lumen_core.h)
M0 — pipeline spike (wlroots→PipeWire→NVENC→file→lumen-core) done & verified on NVIDIA (RTX 5070 Ti / driver 595)
M2 — P1 host → stock Moonlight 🟡 capture+encode landed in M0; pairing/RTSP/vdisplay pending
M3 — measurement harness 🟡 tools/loss-harness runs; latency-probe scaffolded
M4 — P2 transport + Rust client 🟡 GF(2¹⁶) core done; lumen-client-rs scaffolded
M5 — Apple client scaffolded (clients/apple)

lumen-core is complete and verified: it builds and its full test suite (FEC recovery, loopback round-trip under loss, property tests, and a C ABI harness) passes on macOS/aarch64. M0 is done: lumen-host captures a headless wlroots output via the ScreenCast portal + PipeWire, encodes it with NVENC, writes a playable H.265 file, and round-trips every access unit through a lumen_core host→client session (see docs/linux-setup.md). The remaining Linux host backends (KWin/Mutter virtual displays, libei input, web/pairing) are #[cfg(target_os = "linux")] seams — defined and compiling, implementations pending (M2).

Layout

crates/
  lumen-core/        protocol · FEC · pacing · crypto — the C ABI (lib + cdylib + staticlib)
  lumen-host/        Linux host: vdisplay · capture · encode · inject · web (cfg-gated)
  lumen-client-rs/   reference client (M4): VAAPI decode + wgpu present
clients/{apple,android}/   native client scaffolds (import lumen_core.h)
include/lumen_core.h       cbindgen-generated C header (checked in)
tools/{latency-probe,loss-harness}/   measurement (plan §10)
docs/implementation-plan.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/lumen-core/tests/c/run.sh   # standalone C-ABI link+round-trip proof

The C header regenerates from crates/lumen-core/src/abi.rs on every build (cbindgen via build.rs) into include/lumen_core.h.

Design invariants

  • One core, linked everywhere. Protocol/FEC/crypto/pacing live in lumen-core exactly once, exposed over a stable, versioned C ABI (lumen_abi_version(), LumenConfig carries its own struct_size).
  • No async on the hot path. The per-frame pipeline uses native threads only; tokio/quinn are gated behind the off-by-default quic feature (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.

S
Description
next gen game streaming - built using rust, back compatible with game stream clients, and supporting virtual displays for kde/kwin, gnome and gamescope.
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