enricobuehler
fdda7144ed
Phases 1–4 of design/encoder-recovery-hardening.md — make the shipped RFI/ freeze-until-reanchor recovery honest and rebuild-safe across every backend. F1 — frame-index domain desync: the encode loop now owns a session-lifetime `au_seq`; `Encoder::submit_indexed(au_seq + inflight)` pins NVENC inputTimeStamp and AMF LTR slots to the WIRE frame index, so `invalidate_ref_frames` compares client frame numbers in the same domain and survives adaptive-bitrate rebuilds (an internal counter desynced on the first rebuild → RFI silently dead / an AMF force-ref onto a never-decoded frame). `FrameMsg.frame_index` → `Session::seal_frame_at`; GameStream gets the same via `VideoPacketizer:: packetize(.., Some(idx))`. F2 — Windows NVENC left the client frozen ~1s per loss: NVENC RFI was transparent (no anchor tag) while the session glue armed the 750ms IDR cooldown, so the freeze only lifted on the ~1s keyframe re-ask. NVENC now mirrors AMF — `pending_anchor` tags the first post-invalidate AU (the clean re-anchor P-frame) `recovery_anchor`, incl. the covering-range dedupe re-arm; the client lifts at ~RTT. F3 — speed-test probe filler burned video frame indexes: moved to its own index space (`Packetizer::alloc_probe_index` + `Session::submit_probe_frame`) with a second client reassembly window routed on FLAG_PROBE, gated on the new VIDEO_CAP_PROBE_SEQ Hello bit (mid-session probes declined for older clients). F4 — RFI range sanity cap: forward gaps wider than `packet::RFI_MAX_RANGE` (256) resync via keyframe instead of an out-of-range RFI, host- and client-side (client huge-gap → keyframe in `RfiRecovery::observe` + the pf-client-core pump). F5 — reset() parity: Windows NVENC (teardown + lazy re-init), Linux VAAPI (drop-inner), Linux NVENC (reopen from stored OpenArgs) now give the stall watchdog a heal lever instead of ending the session. F6 — sw.rs `pending: VecDeque` (was `Option`), killing the silent AU drop at capturer pipeline depth > 1. F7 — doc sweep on the RFI/anchor comments. Verified: punktfunk-core lib tests (macOS + Linux), full punktfunk-host suite on Linux (RTX 5070 Ti), Windows compile. Owed: the on-glass client matrix (F2 freeze A/B, AMF LTR spike across a bitrate rebuild). Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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) — thepunktfunk/1data 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
nanorslibrary 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/1negotiates this one.
- GF(2⁸) classic Reed–Solomon with the Cauchy generator matrix — byte-identical to the
- Crypto (
crypto.rs) — AES-128-GCM session encryption with per-direction nonce salts and sequence-as-AAD; SPAKE2 PIN pairing lives behind thequicfeature. - QUIC control plane (
quic.rs,client.rs, featurequic) — the Hello/Welcome/Start handshake, cert pinning/TOFU, reverse audio, and the embeddableNativeClientconnector. This is the only placetokio/quinnare allowed; the feature is off by default so the core stays runtime-free. - C ABI (
abi.rs) — the versioned surface (punktfunk_abi_version(),PunktfunkConfigcarrying its ownstruct_size) that generatesinclude/punktfunk_core.hvia 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.
Related
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