sylph-decoder b82f75979e re: the dual-mono explanation for the extra stream bytes does not generalise
The port chose a voice presentation on the argument that ADV chunk 1 is
mono-in-stereo and chunk 2 is dual-mono, so chunk 2 s extra bytes encode a
duplicated channel rather than fidelity -- which would explain its higher
declared PsuedoBytesPerSec without appealing to encode quality.

Their ADV channel measurement stands. The generalisation does not. If stream 3
were systematically the same take with its channel duplicated, its size ratio to
stream 2 would be tight across the 28 three-stream cues. Measured:

  min 0.0778 (S00A, the silent one)
  median 1.2565
  max 2.9163 (S06A)
  sd 0.5057
  within 15 percent of 1.0: 12 of 28

A 37x spread is not a duplicated channel, and the declared rates scatter with
them -- S06A is 5661 against 16513 B/s. Whatever distinguishes the three streams
varies per cue rather than being a fixed channel-configuration triple.

This does not touch the port s decision, which is to take the loudest
presentation: that is a per-asset content measurement, not a structural rule, so
a scattering ratio cannot undermine it. It touches the explanation, which should
not harden into a fact about the format.

Two curiosities recorded: S12B s three streams are byte-size identical at 14396
each, and BIRD_224 is 3-stream while being a non-movie cue, so the shape is not
exclusive to cutscenes.

Also narrows the settle-time page s own generalisation. The port measured its
boot the way this corpus measured the game and found the sequencer NOT late --
its 0.6 s discrepancy was arrival-to-arrival timestamps compared against visible
spans, the plate-delay trap in a second place. So what is supported is that
rest.t is the wrong landmark for the TITLE, not that everything paced off it is
late. And the offered re-take of the one-run menu figures is recorded as
declined, with the reason, rather than left looking unfinished.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01QsEPXWVaEpyfudtR6re1Pd
2026-08-29 15:37:46 +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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