ff04fbce52
Checking my export against the Decoder's declared XMA1 durations turned up a
defect of mine that has been shipping since P6.
`export_bgm` summed every sub-wave `media` returned and scaled by 1/n. Decoded
and timed, all three banks have the same shape:
BGM_103 sub-wave 0: 10300 B -> 0.009 s, peak -inf 1: 87.744 s 2: 87.744 s
BGM_102 sub-wave 0: 10300 B -> 0.009 s, peak -inf 1: 37.482 s 2: 37.482 s
BGM_001 sub-wave 0: 10300 B -> 0.009 s, peak -inf 1: 173.809 s 2: 173.809 s
Sub-wave 0 is DIGITALLY SILENT in all three, and 10300 B is 10240 plus a 60-byte
RIFF wrapper -- 10240 being exactly the bank header the Decoder's census
identifies. Counting it in the divisor put every real stem at 1/3 instead of 1/2:
3.52 dB on all the menu music since P6. Dropping a silent input is arithmetic,
not a decoding decision. Measured after: main_menu.ogg -7.69 -> -4.20 dBFS,
+3.49 dB against 3.52 predicted.
THIRD INSTANCE OF ONE DEFECT: a silent chunk in the voice sum, a silent channel
in the mono fold, now a silent sub-wave in the music sum. Each invisible to every
check except a level, and each time the divisor was computed from how many inputs
there are rather than how many carry signal. That is the shape, not the bug.
Closes a red row open since P6 -- "sound_bank_riffs returns three sub-waves where
Q10's census says two". The census was right, and this corroborates the Decoder's
c1f3608 by decoding rather than by counting headers. The export reports 2
sub-waves and the warning is gone.
REFUTATION ATTEMPT, conclusion survives and the reasoning does not: the Decoder
explained BGM_001 as "173.821 s declared against your decoded 167.663 s, a gap of
6.158 s -- declared is the encoded stream, decoded is where the audio stops." A
full decode yields 173.809 s of PCM, not 167.663. The 167.663 is where the music
FADES OUT, measured from the audio; the stream continues silent to its declared
end. Declared and decoded agree to 12 ms, and the trailing silence is inside the
decode rather than the difference between two methods. The cross-check is
stronger than stated -- three banks, 5-12 ms -- and the explanation should go.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01N7FiFFFwbvG2uxdcEh8HyF
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.