f34d24941d
The port hit `sound_bank_riffs("BGM_103.slb")` returning three against a census
that says two, and refused to guess which to drop. It was our reader.
`to_xma_riffs`'s hybrid branch derives a leading packet stream's start as
`first_riff % XMA1_PACKET`. That is right only when the bank header is smaller
than one 2048-byte packet -- true of the voice banks the branch was written for
(1392/1468/1600/1728), false of a music bank, whose header is exactly five
packets. The modulus returned 0 and the whole 10 240-byte header was emitted as
sub-wave 0.
The header states its own length, so the guard needs no threshold: BE u32 0x800
at +0x18 with the bank id repeated at +0x00 and +0x20, header length in blocks at
+0x24. Disc-wide over sound.pak's 9 519 entries, 28 match at offset 0 -- every
music bank, ids 1001-1023 and 1101-1105 -- and on 28/28 the declared header ends
EXACTLY at the first RIFF. Zero have a gap, so a header and a leading packet
stream never coexist here; zero false positives among the other 9 491.
Controlled rather than argued: decoding the emitted region through the same
chain, on the same bank, in the same run gives 0.009 s of PCM where the bank's
real wave 0 gives 87.744 s against a declared 87.75. The region is also 99.1%
zero bytes. And the oracle had already said two -- the XMA probe at the main menu
saw exactly two streams, at BGM_103's two declared wave sizes.
BGM_106-109 are deliberately NOT in the 28: their entries start mid-bank, so they
have no header at offset 0 and their leading region is real audio. The
VOICE_D_453 recovery is untouched and its tests still pass, 10/10 green.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_014voBspJ6kFncNErZJuZcLw
Sylpheed
A clean-room reverse engineering and port project for Project Sylpheed: Arc of Deception (Xbox 360, 2007).
Three things live here, in one repository so that a change spanning them lands as one commit:
| The decoders | crates/sylpheed-formats — the disc's formats, read and verified disc-wide |
| The port | port/ — a Godot 4 project, plus crates/sylpheed-export which converts a disc into the open asset tree it reads |
| The corpus | docs/re/ — what has been reverse engineered, with its evidence, its retractions and its dead ends |
You need your own copy of the game. No game content is in this repository and none ever will be. The exporter reads the disc you supply.
The oracle is the real game
sylpheed-cliand the Explorer are tools for verifying our decoding. They are hypotheses under test and they have been wrong. When something must be checked against the truth, the truth is the game running in Xenia Canary, captured — not any renderer of ours.
This is stated first because getting it backwards is the most expensive mistake this project has made.
Layout
crates/
sylpheed-formats/ the decoders. Disc-wide verified; the corpus is its spec
sylpheed-cli/ headless tools -- render a screen, dump a table, probe audio
sylpheed-viewer/ the Explorer: a human's window onto the disc. STATIC data only
sylpheed-export/ disc -> the open, moddable asset tree
port/ the Godot 4 project. Reads open formats ONLY
authored/ decisions that are NOT on the disc, each with its reason
data/
base/ generated by the exporter. Gitignored, never hand-edited
mods/ drop-in overrides. Yours
docs/
re/ the corpus: findings, refutations, method traps
game/ how the game is navigated -- menus, modals, flight
port/ the port's mission, its handoff contract, modding rules
agents/ how the agent team works together
tools/ capture harnesses, probes, the share tool
exchange/ transient inter-agent files. NOT in git
docker/ the agent containers
Where to start
docs/re/INDEX.md— what is decodeddocs/re/REFUTED.md— what has been tested and dieddocs/re/METHOD.md— traps this project has already paid fordocs/game/navigation.md— how the game is navigateddocs/port/MODDING.md— why the asset tree looks the way it does
Xenia Canary is a separate repository: it is a fork tracking upstream, and it carries our instrumentation.
Conventions
Confidence is per claim, never per document: ✅ CONFIRMED · 🟡 PROBABLE ·
❔ HYPOTHESIS · ❌ REFUTED. A withdrawn result is kept with its reasoning
rather than deleted — that is why the numbers here can be trusted.