a9755170ee
The placement region is `frames` records of `{u32 time; 36-byte pose}` after an
8-byte header, so the time word PRECEDES the pose it belongs to. Our parser's
40-byte window opened at the pose, four bytes into the record, and then read the
word at its `+36` as that pose's time -- which is the NEXT pose's. Every pose
field was right; only the time association slipped by one.
Two things the corpus has carried for weeks are that off-by-one and nothing
else: "a group's data stops 4 bytes short of its final block's time slot", and
"the last keyframe carries no time". The group is not short (8 + frames*40 is
exact) and no time is missing -- the first pose's time is the lead-in word at
`header + 8` that `parse_placements` skipped without asking what it was.
Disc-wide, 33 archives, 13 991 groups, each test with a control:
A lead-in prepended to the shifted times is non-decreasing 13991/13991
B a non-zero lead-in is strictly below the next time 5058/5058
control (another group's lead-in, same bundle) 70.9%
C multi-segment alpha ramp at a constant rate, corrected 857/1540
the same, under the old reading 0/1042
C is the one that cannot be argued with: interpolation between keyframes is
linear, and under the old reading not one multi-keyframe ramp on the disc comes
out at a constant rate.
Adoption is free on every static composite, which is what the corpus previously
declined it over. `SYLPHEED_KF_TIME_SHIFT=1` moved GP_TITLE build 7 by 13.1% of
its pixels because it left pose 0 untimed; with the lead-in restored, all 12
GP_TITLE builds render byte-identically, and across 217 builds in six archives
only two elements pick a different rest pose -- both times between two poses
that are equally invisible.
`SYLPHEED_KF_TIME_SHIFT` is gone; `SYLPHEED_KF_TIME_LEGACY=1` restores the old
reading for A/B work.
ui_header_time_disc needed one line: 546 bundles whose every group is a single
static pose now report max_time = 0 where they previously reported no time at
all. Excluding them, the result it guards strengthened -- the bound holds over
2 859 bundles instead of 2 313, still with zero violations.
Not established: the executable's own parser. Reach is written down.
docs/re/ui-keyframe-record-layout.md
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Nsxw1A9JseUw99Yw1ZRQzY
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.