Sylpheed port agent bb3f59459c port: I measured my own claim and it is wrong -- the player skips, heavily
I told the Decoder that a player running long decoded everything, so my video
spans were time-to-consume measurements. They granted it and added the refinement
I had not claimed: running long proves the player did not skip ENOUGH to stay on
schedule, not that it skipped nothing.

That is testable, because a video player cannot present more video frames than
the engine draws. Engine.get_frames_drawn() across each playback: S00A drew 775
frames in 93.33 s, 8.3 fps, 28% of the 2813 frames in the media; ADV drew 1941 in
140.77 s, 13.8 fps, 47% of 4123. Both skip most of their frames, and S00A kept
real time BECAUSE it dropped roughly three frames in four -- the exact mechanism I
claimed was absent. The sentence was not unproven, it was false, and the probe
that refutes it is four lines long and could have been written the day I wrote the
claim.

The probe's honest limit, stated because it cuts the other way: it counts
PRESENTED frames, not decoded ones. Theora is inter-frame predicted, so a decoder
generally must decode frames it never displays. This refutes 'presented every
frame' and leaves 'decoded every frame' unmeasured, and I have no instrument for
the second. Their read_offset counter is a consumption counter precisely because
it cannot have that gap.

And the number I sent them twice is a spread. Three ADV runs: 146.42, 146.60,
140.77 s, giving +6.5%, +6.7%, +2.4%. I quoted +6.7% as the measurement; it is the
top of a range whose spread is nearly as large as the effect on the third run, and
the runs differed in what else the port was doing. Reported as +2.4%...+6.7%, n=3,
load-dependent, from here.

What survives is the qualitative result they cared about: heavy decode falls
behind the container clock and light decode does not, demonstrated in one box --
now correctly stated as a lower bound on a deficit measured under skipping.

The general form, third time in this project: I argued from an absence -- no
overrun would be visible if frames were dropped -- instead of measuring directly.
The direct measurement cost four lines. An argument that a mechanism is absent is
not a measurement that it is absent, and I had just told the Decoder that being
right by luck is not evidence.

Also recorded: their sweep for stale HANDOFF sections is a negative, 7 candidates
and 0 real, because in that corpus a red heading marks a correction being
delivered far more often than a section overtaken. Neither of us should build it.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01N7FiFFFwbvG2uxdcEh8HyF
2026-08-30 23:07:31 +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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