Files

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enricobuehlerandClaude Fable 5 9b7fc127ef feat(core): Automatic bitrate scales to measured link capacity — probe ceiling + slow start

The ABR ceiling was the negotiated start rate, so an 'Automatic' session
was permanently boxed at the 20 Mbps default no matter the link — the
most user-visible cap left after the transport work lifted the client
receive ceiling to ~4.8 Gbps wire.

- Startup link-capacity probe: ~2 s into an Automatic session the pump
  fires one speed-test burst (2 Gbps target, 800 ms) over the existing
  ProbeRequest machinery; delivered wire throughput x0.7 (FEC + variance
  headroom) becomes the controller's climb ceiling via set_ceiling().
  Old hosts decline (all-zero reply) or never answer (a 6 s timeout
  clears the stuck probe state so LossReports resume) — the ceiling then
  stays negotiated, exactly the old behavior. PUNKTFUNK_ABR_PROBE=0
  opts out.
- Slow start: until the first congestion signal, every cooled clean
  window DOUBLES the rate toward the ceiling (20 Mbps -> 640 Mbps in
  ~10 s) instead of +6% per ~10 s (which would have taken ~10 minutes).
  Any congestion signal ends it for good; classic AIMD takes over.
- Faster, severity-aware AIMD: a SEVERE window (unrecoverable frame,
  jump-to-live flush, or >=6% loss) backs off x0.7 immediately instead
  of waiting two windows; ordinary congestion (2-6% loss, OWD rise)
  keeps the two-window fuse. Additive climbs need 6 clean windows
  (~4.5 s, was ~10 s); the change cooldown drops 3 s -> 1.5 s.
- PUNKTFUNK_VBV_FRAMES now also scales the direct-NVENC VBV (Windows +
  Linux, previously hardwired to 1 frame) — parity with AMF/VAAPI/QSV.

Each accepted step still costs an encoder rebuild + IDR on the host;
in-place rate reconfigure (NvEncReconfigureEncoder / AMF dynamic
properties / Vulkan per-frame RC) is the planned follow-up that makes
stepping free. Controller tests rewritten to the new policy (severity
classes, slow-start climb, ceiling semantics; 144 green).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

2026-07-14 19:28:11 +02:00

benches

fix(core): receive path — replay window covers the loss window, zero-alloc open

2026-07-10 14:55:06 +02:00

src

feat(core): Automatic bitrate scales to measured link capacity — probe ceiling + slow start

2026-07-14 19:28:11 +02:00

tests

perf(core): ref-based FEC encode — packetize shards reference the frame in place

2026-07-10 15:16:07 +02:00

vendor/fec-rs

rename: lumen → punktfunk, everywhere

2026-06-10 13:11:59 +00:00

build.rs

rename: lumen → punktfunk, everywhere

2026-06-10 13:11:59 +00:00

Cargo.toml

feat(transport): Windows DSCP via qWAVE flows — PUNKTFUNK_DSCP now real on the wire there

2026-07-10 15:59:23 +02:00

cbindgen.toml

fix(core,host): make the native data plane survive real Wi-Fi links

2026-07-07 07:35:08 +02:00

README.md

docs: repo-wide housekeeping — sync README & docs with the code as shipped

2026-07-10 09:13:42 +02:00

README.md

punktfunk-core

The shared protocol core — the one place where punktfunk's transport, forward error correction, and crypto live. It's linked into the host and every native client, so there's exactly one implementation of the wire format everywhere.

Written in Rust with no async on the per-frame path (native threads only). It exposes both a normal Rust API and a stable, versioned C ABI, so the Swift and Kotlin clients — and any C embedder — link the same code as the Rust ones.

What's in here

Transport & session (session.rs, transport/, packet.rs) — the punktfunk/1 data plane over raw UDP: packetization, reassembly (with attacker-bounded limits), pacing, and socket tuning.
FEC (fec/) — the wall-breaker. Two codes:
- GF(2⁸) classic Reed–Solomon with the Cauchy generator matrix — byte-identical to the nanors library Moonlight uses, so our parity is decodable by a stock Moonlight client.
- GF(2¹⁶) Leopard-RS (SIMD, O(n log n)) — up to 65535 shards/block, which removes the ~1 Gbps FEC ceiling. punktfunk/1 negotiates this one.
Crypto (crypto.rs) — AES-128-GCM session encryption with per-direction nonce salts and sequence-as-AAD; SPAKE2 PIN pairing lives behind the quic feature.
QUIC control plane (quic.rs, client.rs, feature quic) — the Hello/Welcome/Start handshake, cert pinning/TOFU, reverse audio, and the embeddable NativeClient connector. This is the only place tokio/quinn are allowed; the feature is off by default so the core stays runtime-free.
C ABI (abi.rs) — the versioned surface (punktfunk_abi_version(), PunktfunkConfig carrying its own struct_size) that generates include/punktfunk_core.h via cbindgen at build time.

Build outputs

The crate builds three ways at once (crate-type = ["lib", "cdylib", "staticlib"]):

Output	Used by
`lib` (rlib)	the host, probe, and tools link it as a normal Rust crate
`cdylib` (`.so`/`.dylib`)	the Swift / Kotlin clients via the C ABI
`staticlib` (`.a`)	the C test harness and static embedding

Test

cargo test -p punktfunk-core                 # unit + proptest + loopback
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

Design invariants (do not regress)

One core, linked everywhere — protocol/FEC/crypto live only here, behind the stable C ABI.
No async on the hot path — the per-frame pipeline is native threads only; quic (tokio/quinn) is control-plane only, feature-gated, off by default.
Security hardening stays intact — the reassembler bounds attacker-controlled fields before allocating; AES-GCM keeps per-direction nonce salts + seq-as-AAD; the ABI checks struct_size. Regression tests exist — keep them green.

punktfunk-host — the streaming host built on this core
Clients — the apps that link this core over the C ABI (or directly, in Rust)
punktfunk-planning: implementation-plan.md (internal planning repo) — why GF(2¹⁶) FEC, the latency budget, and the architecture thesis

README.md Unescape Escape

punktfunk-core

What's in here

Build outputs

Test

Design invariants (do not regress)

Related

README.md