sylph-decoder d4a08ad194 re: a nested record's +0x08 is its loop length -- the plate's period is 120, not 105
Answers the question the port agent asked: does the `PRESS A` plate's pulse
group loop from its start, or hold at alpha 0 between cycles? It holds.

A nested record is itself a RATC bundle with its own header, and that header's
`+0x08` is the loop length -- the same field ui_header_time_disc already tests
as an animation length at the top level. Its keyframes need not fill it, and
the slack is a hold at the final pose. `ptbtn00f` is 105 units of ramp inside
a 120-unit cycle, so the glow rests dark for 15 units between pulses. The five
main-menu focus records fill their 120 exactly, which is what shows the slack
belongs to this record rather than to the format.

Disc-wide over 1 781 timed nested records: 92.3% declare exactly their last
keyframe time, 7.7% declare more, and 0 declare less. That last row is the
falsifier -- a cycle cannot restart before its own last pose -- and it never
fires; the 7.7% is what keeps the reading from being an unfalsifiable
relabelling of the keyframes.

Falsification against the running game, using a pacing factor measured
INDEPENDENTLY on the main menu's focus ring (declared 120 units, measured
2.177 s, factor 1.0885): to reach the corpus's four measurements of the plate
pulse (2.12/2.19/2.34/2.31 s), a 105-unit period needs a factor of 1.211-1.337,
which EXCLUDES the ring's; a 120-unit period needs 1.060-1.170, which CONTAINS
it. Predicted 2.177 s against a measured 2.12-2.34. The two elements are in
different bundles and were measured in separate runs; the only thing tying
them together is that both declare 120.

So the port should stop shipping 105. Its 123-vs-129 ambiguity straddled the
right answer without containing it, and 129 only fitted because it was
105 + the exit_ramp_units constant it has since correctly deleted.

Reach is stated: this says where a cycle ends, not which records cycle, and
the TOP-level +0x08 is a different field left untouched -- every GP_TITLE
entry declares 300 while its elements end at 244-269.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01QsEPXWVaEpyfudtR6re1Pd
2026-08-29 19:40:23 +00:00

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-cli and 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

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.

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