feat: M2 P1.5 (FEC) — nanors-exact Reed-Solomon recovery for the video stream

Moonlight now reconstructs lost video shards from our parity (verified live:
under induced packet loss the picture recovers cleanly instead of failing with
"network connection too bad"; 0% added loss in normal operation).

The decisive finding: Moonlight's nanors uses a CAUCHY generator matrix
(M[j][i] = inv[(m+i)^j], GF(2^8) poly 0x1d), while reed-solomon-erasure is
Vandermonde — so its parity was NOT Moonlight-decodable, despite the old
gf8.rs comment claiming equivalence.

lumen-core:
- Swap the GF(2^8) backend from reed-solomon-erasure to a vendored fec-rs
  (vendor/fec-rs, BSD-2), which builds the byte-identical Cauchy matrix. Pure
  Rust, no FFI — keeps the "one core" hot path. This makes both lumen's own
  protocol and the GameStream parity nanors-compatible.
- Lock it with a regression test against real nanors vectors
  (k=4,m=2 [10,20,30,40] -> parity [136,0]) + an independent matrix-derived
  cross-check + an erase/recover round-trip. Existing FEC/loopback tests stay
  green, so lumen's own protocol is unaffected.

lumen-host video.rs:
- Generate m = ceil(k*pct/100) parity shards per FEC block via Gf8Coder; stamp
  fecInfo with the recomputed wire pct (100*m/k) so the client derives the same
  count; cap per-block data to 255*100/(100+pct) so k+m <= 255.
- CRITICAL byte-exactness: RS runs over the whole `blocksize` shard (Moonlight
  decodes packetSize+16 bytes from the datagram start and PACKET_RECOVERY_FAILUREs
  on a bad reconstructed `flags` byte). So the NV header fields RS must reproduce
  (streamPacketIndex/frameIndex/flags/multiFec*) are written into data shards
  BEFORE encode, and only the transport fields (RTP header/seq/timestamp +
  fecInfo) are stamped AFTER — leaving the flags byte RS-covered. Matches
  Sunshine stream.cpp. Unit-tested incl. flags recovery.
- fec_percentage wired from stream.rs (Sunshine default 20, LUMEN_FEC_PCT
  override; 0 = data-only). LUMEN_VIDEO_DROP injects loss to test recovery.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
This commit is contained in:
2026-06-09 11:34:27 +00:00
parent 278a6330de
commit 72f8c05aa3
14 changed files with 2921 additions and 212 deletions
Generated
+66 -133
View File
@@ -37,17 +37,6 @@ dependencies = [
"subtle",
]
[[package]]
name = "ahash"
version = "0.7.8"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "891477e0c6a8957309ee5c45a6368af3ae14bb510732d2684ffa19af310920f9"
dependencies = [
"getrandom 0.2.17",
"once_cell",
"version_check",
]
[[package]]
name = "aho-corasick"
version = "1.1.4"
@@ -357,7 +346,7 @@ version = "0.70.1"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "f49d8fed880d473ea71efb9bf597651e77201bdd4893efe54c9e5d65ae04ce6f"
dependencies = [
"bitflags 2.13.0",
"bitflags",
"cexpr",
"clang-sys",
"itertools",
@@ -376,7 +365,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "993776b509cfb49c750f11b8f07a46fa23e0a1386ffc01fb1e7d343efc387895"
dependencies = [
"annotate-snippets",
"bitflags 2.13.0",
"bitflags",
"cexpr",
"clang-sys",
"itertools",
@@ -403,12 +392,6 @@ version = "0.8.0"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "5e764a1d40d510daf35e07be9eb06e75770908c27d411ee6c92109c9840eaaf7"
[[package]]
name = "bitflags"
version = "1.3.2"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "bef38d45163c2f1dde094a7dfd33ccf595c92905c8f8f4fdc18d06fb1037718a"
[[package]]
name = "bitflags"
version = "2.13.0"
@@ -650,6 +633,25 @@ dependencies = [
"libc",
]
[[package]]
name = "crossbeam-deque"
version = "0.8.6"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "9dd111b7b7f7d55b72c0a6ae361660ee5853c9af73f70c3c2ef6858b950e2e51"
dependencies = [
"crossbeam-epoch",
"crossbeam-utils",
]
[[package]]
name = "crossbeam-epoch"
version = "0.9.18"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "5b82ac4a3c2ca9c3460964f020e1402edd5753411d7737aa39c3714ad1b5420e"
dependencies = [
"crossbeam-utils",
]
[[package]]
name = "crossbeam-utils"
version = "0.8.21"
@@ -838,13 +840,20 @@ version = "2.4.1"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "9f1f227452a390804cdb637b74a86990f2a7d7ba4b7d5693aac9b4dd6defd8d6"
[[package]]
name = "fec-rs"
version = "0.1.0"
dependencies = [
"rayon",
]
[[package]]
name = "ffmpeg-next"
version = "7.1.0"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "da02698288e0275e442a47fc12ca26d50daf0d48b15398ba5906f20ac2e2a9f9"
dependencies = [
"bitflags 2.13.0",
"bitflags",
"ffmpeg-sys-next",
"libc",
]
@@ -1078,15 +1087,6 @@ dependencies = [
"tracing",
]
[[package]]
name = "hashbrown"
version = "0.12.3"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "8a9ee70c43aaf417c914396645a0fa852624801b24ebb7ae78fe8272889ac888"
dependencies = [
"ahash",
]
[[package]]
name = "hashbrown"
version = "0.15.5"
@@ -1239,15 +1239,6 @@ dependencies = [
"generic-array",
]
[[package]]
name = "instant"
version = "0.1.13"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "e0242819d153cba4b4b05a5a8f2a7e9bbf97b6055b2a002b395c96b5ff3c0222"
dependencies = [
"cfg-if",
]
[[package]]
name = "is_terminal_polyfill"
version = "1.70.2"
@@ -1381,7 +1372,7 @@ version = "0.9.2"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "b6b8cfa2a7656627b4c92c6b9ef929433acd673d5ab3708cda1b18478ac00df4"
dependencies = [
"bitflags 2.13.0",
"bitflags",
"cc",
"convert_case",
"cookie-factory",
@@ -1431,15 +1422,6 @@ dependencies = [
"lumen-core",
]
[[package]]
name = "lru"
version = "0.7.8"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "e999beba7b6e8345721bd280141ed958096a2e4abdf74f67ff4ce49b4b54e47a"
dependencies = [
"hashbrown 0.12.3",
]
[[package]]
name = "lru-slab"
version = "0.1.2"
@@ -1462,10 +1444,10 @@ dependencies = [
"aes-gcm",
"bytes",
"cbindgen",
"fec-rs",
"proptest",
"quinn",
"rand 0.9.4",
"reed-solomon-erasure",
"reed-solomon-simd",
"thiserror 2.0.18",
"tokio",
@@ -1593,7 +1575,7 @@ version = "0.30.1"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "74523f3a35e05aba87a1d978330aef40f67b0304ac79c1c00b294c9830543db6"
dependencies = [
"bitflags 2.13.0",
"bitflags",
"cfg-if",
"cfg_aliases",
"libc",
@@ -1757,17 +1739,6 @@ version = "2.2.1"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "f38d5652c16fde515bb1ecef450ab0f6a219d619a7274976324d5e377f7dceba"
[[package]]
name = "parking_lot"
version = "0.11.2"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "7d17b78036a60663b797adeaee46f5c9dfebb86948d1255007a1d6be0271ff99"
dependencies = [
"instant",
"lock_api",
"parking_lot_core 0.8.6",
]
[[package]]
name = "parking_lot"
version = "0.12.5"
@@ -1775,21 +1746,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "93857453250e3077bd71ff98b6a65ea6621a19bb0f559a85248955ac12c45a1a"
dependencies = [
"lock_api",
"parking_lot_core 0.9.12",
]
[[package]]
name = "parking_lot_core"
version = "0.8.6"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "60a2cfe6f0ad2bfc16aefa463b497d5c7a5ecd44a23efa72aa342d90177356dc"
dependencies = [
"cfg-if",
"instant",
"libc",
"redox_syscall 0.2.16",
"smallvec",
"winapi",
"parking_lot_core",
]
[[package]]
@@ -1800,7 +1757,7 @@ checksum = "2621685985a2ebf1c516881c026032ac7deafcda1a2c9b7850dc81e3dfcb64c1"
dependencies = [
"cfg-if",
"libc",
"redox_syscall 0.5.18",
"redox_syscall",
"smallvec",
"windows-link",
]
@@ -1843,7 +1800,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "9688b89abf11d756499f7c6190711d6dbe5a3acdb30c8fbf001d6596d06a8d44"
dependencies = [
"anyhow",
"bitflags 2.13.0",
"bitflags",
"libc",
"libspa",
"libspa-sys",
@@ -1954,7 +1911,7 @@ checksum = "4b45fcc2344c680f5025fe57779faef368840d0bd1f42f216291f0dc4ace4744"
dependencies = [
"bit-set",
"bit-vec",
"bitflags 2.13.0",
"bitflags",
"num-traits",
"rand 0.9.4",
"rand_chacha 0.9.0",
@@ -2126,6 +2083,26 @@ dependencies = [
"rand_core 0.9.5",
]
[[package]]
name = "rayon"
version = "1.12.0"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "fb39b166781f92d482534ef4b4b1b2568f42613b53e5b6c160e24cfbfa30926d"
dependencies = [
"either",
"rayon-core",
]
[[package]]
name = "rayon-core"
version = "1.13.0"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "22e18b0f0062d30d4230b2e85ff77fdfe4326feb054b9783a3460d8435c8ab91"
dependencies = [
"crossbeam-deque",
"crossbeam-utils",
]
[[package]]
name = "rcgen"
version = "0.13.2"
@@ -2145,35 +2122,13 @@ version = "0.1.1"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "08ad765b21a08b1a8e5cdce052719188a23772bcbefb3c439f0baaf62c56ceac"
[[package]]
name = "redox_syscall"
version = "0.2.16"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "fb5a58c1855b4b6819d59012155603f0b22ad30cad752600aadfcb695265519a"
dependencies = [
"bitflags 1.3.2",
]
[[package]]
name = "redox_syscall"
version = "0.5.18"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "ed2bf2547551a7053d6fdfafda3f938979645c44812fbfcda098faae3f1a362d"
dependencies = [
"bitflags 2.13.0",
]
[[package]]
name = "reed-solomon-erasure"
version = "6.0.0"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "7263373d500d4d4f505d43a2a662d475a894aa94503a1ee28e9188b5f3960d4f"
dependencies = [
"libm",
"lru",
"parking_lot 0.11.2",
"smallvec",
"spin",
"bitflags",
]
[[package]]
@@ -2278,7 +2233,7 @@ version = "1.1.4"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "b6fe4565b9518b83ef4f91bb47ce29620ca828bd32cb7e408f0062e9930ba190"
dependencies = [
"bitflags 2.13.0",
"bitflags",
"errno",
"libc",
"linux-raw-sys",
@@ -2434,7 +2389,7 @@ version = "3.7.0"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "b7f4bc775c73d9a02cde8bf7b2ec4c9d12743edf609006c7facc23998404cd1d"
dependencies = [
"bitflags 2.13.0",
"bitflags",
"core-foundation",
"core-foundation-sys",
"libc",
@@ -2829,7 +2784,7 @@ dependencies = [
"bytes",
"libc",
"mio",
"parking_lot 0.12.5",
"parking_lot",
"pin-project-lite",
"signal-hook-registry",
"socket2",
@@ -3257,7 +3212,7 @@ version = "0.244.0"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "47b807c72e1bac69382b3a6fb3dbe8ea4c0ed87ff5629b8685ae6b9a611028fe"
dependencies = [
"bitflags 2.13.0",
"bitflags",
"hashbrown 0.15.5",
"indexmap",
"semver",
@@ -3282,7 +3237,7 @@ version = "0.31.14"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "645c7c96bb74690c3189b5c9cb4ca1627062bb23693a4fad9d8c3de958260144"
dependencies = [
"bitflags 2.13.0",
"bitflags",
"rustix",
"wayland-backend",
"wayland-scanner",
@@ -3294,7 +3249,7 @@ version = "0.32.12"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "563a85523cade2429938e790815fd7319062103b9f4a2dc806e9b53b95982d8f"
dependencies = [
"bitflags 2.13.0",
"bitflags",
"wayland-backend",
"wayland-client",
"wayland-scanner",
@@ -3306,7 +3261,7 @@ version = "0.3.12"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "6e9567599ef23e09b8dad6e429e5738d4509dfc46b3b21f32841a304d16b29c8"
dependencies = [
"bitflags 2.13.0",
"bitflags",
"wayland-backend",
"wayland-client",
"wayland-protocols",
@@ -3319,7 +3274,7 @@ version = "0.3.12"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "eb04e52f7836d7c7976c78ca0250d61e33873c34156a2a1fc9474828ec268234"
dependencies = [
"bitflags 2.13.0",
"bitflags",
"wayland-backend",
"wayland-client",
"wayland-protocols",
@@ -3365,22 +3320,6 @@ dependencies = [
"rustls-pki-types",
]
[[package]]
name = "winapi"
version = "0.3.9"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "5c839a674fcd7a98952e593242ea400abe93992746761e38641405d28b00f419"
dependencies = [
"winapi-i686-pc-windows-gnu",
"winapi-x86_64-pc-windows-gnu",
]
[[package]]
name = "winapi-i686-pc-windows-gnu"
version = "0.4.0"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "ac3b87c63620426dd9b991e5ce0329eff545bccbbb34f3be09ff6fb6ab51b7b6"
[[package]]
name = "winapi-util"
version = "0.1.11"
@@ -3390,12 +3329,6 @@ dependencies = [
"windows-sys 0.61.2",
]
[[package]]
name = "winapi-x86_64-pc-windows-gnu"
version = "0.4.0"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "712e227841d057c1ee1cd2fb22fa7e5a5461ae8e48fa2ca79ec42cfc1931183f"
[[package]]
name = "windows-link"
version = "0.2.1"
@@ -3703,7 +3636,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "9d66ea20e9553b30172b5e831994e35fbde2d165325bec84fc43dbf6f4eb9cb2"
dependencies = [
"anyhow",
"bitflags 2.13.0",
"bitflags",
"indexmap",
"log",
"serde",