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I wrote that BGM_001 s declared 173.821 s disagreed with a decoded 167.663 s, and explained the gap as declared covering the encoded stream including trailing silence while decoded is where the audio stops. The port decoded it fully: the bank yields 173.809 s of PCM. There is no disagreement -- 167.663 s is where the music fades out, measured from the audio, and the stream continues silent to its declared end inside that same decode. So the declared-rate method is better than this page claimed, and is now cross-checked on three banks against independent decodes: BGM_103 87.750 vs 87.744, BGM_102 37.487 vs 37.482, BGM_001 173.821 vs 173.809 -- agreement 5 to 12 ms. The conclusion survives unchanged and is the useful half: trust it for lengths, not for musical boundaries. A declared length includes whatever silence the encode carries, so it is not a loop point. Also records in METHOD a defect shape the port hit three times in one pipeline, each invisible to every check except a level: normalising by how many inputs there are rather than how many carry signal. A silent chunk in a voice sum, a silent channel in a mono fold, and a silent sub-wave -- the 10240-byte bank header wrapped to 10300 B -- counted as a third stem in a music sum, which put every real stem at 1/3 instead of 1/2 and cost 3.52 dB on all menu music for two iterations. This corpus s census said two waves and the exporter s divisor said three; the count that disagrees with a census is the one that is wrong. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01QsEPXWVaEpyfudtR6re1Pd
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.