Sylpheed port agent 579c8096c1 port: P4 -- the intro video plays inside the boot sequence
The exporter transcodes ADV.wmv and S00A.wmv to Ogg Theora and records the exact
ffmpeg command in the manifest, per MISSION §6, so a modder who dislikes the
quality re-runs one line rather than reverse-engineering what was done.

Quality was MEASURED, not judged: SSIM against the decoded source over a 10 s
sample is 0.9863 / 0.9896 / 0.9924 at -q:v 6 / 8 / 10, and at 200 % zoom on the
reel's hardest case -- fine serif text and soft gradients over near-black, where
Theora breaks first -- q8 is indistinguishable. So MISSION §6's permitted
FFmpeg-GDExtension fallback is NOT needed and is NOT being proposed. No new
runtime dependency.

-ac 2 because the source is 6-channel WMA Pro; that downmix is a decision, so it
lives in the recorded command rather than in prose.

Encoding is cached on a .cmd sidecar holding the command and the source size --
any change to either re-encodes. export/ is still regenerated wholesale; this is
derived state validating derived state, not a hand-edit, and without it every
re-export pays ~4 minutes to produce a byte-identical file.

The player renders INTO the design SubViewport. Parenting it to the Boot node
played the movie to the window instead, and every captured frame came out black
-- which is worth more than a capture-bug note: a movie outside the 1280x720
design space is outside the coordinate system every screen is expressed in.

(A) skips a movie, because Q9 measured that (title at 57 s vs a 193 s baseline).

NOT VERIFIED, and stated as such: audible playback. This container has no audio
device and Godot falls back to the dummy driver. The Vorbis stream exists, is
2-channel and decodes; whether Godot emits it is unconfirmed.
2026-08-29 08:44:25 +00:00

Sylpheed Godot

A clean-room Godot 4 port of Project Sylpheed: Arc of Deception, starting with the menu shell: developer splash → intro video → title → main menu → submenus.

You need your own copy of the game. Nothing in this repository is game content. An offline exporter reads the disc you supply and writes an open, moddable asset tree; the Godot project reads only that tree and never touches a disc format.

  your disc  ──▶  crates/sylpheed-export  ──▶  export/   ──▶  port/  (Godot 4)
                  (Rust; decoders come from      JSON + PNG        reads ONLY
                   sylpheed-formats)             + OGG + OGV       open formats

Why the wall

Two reasons, and the second is the interesting one:

  1. Godot cannot read IPFB archives, RATC bundles, T8aD textures, XMA banks or WMV video, and it should not learn to.
  2. Modding is a goal of this port. If the runtime reads the original formats, modding means reverse engineering. If it reads JSON and PNG, modding means opening a file.

Where the knowledge comes from

The decoders live in sylpheed-formats, pinned by revision — a separate project, where the reverse engineering happens. Its docs/port/HANDOFF.md is the contract: what has been decoded, what was measured off the running game, and what is known to be undecodable. Read it before assuming a value is on the disc.

Layout

crates/sylpheed-export/ disc → open formats. Regenerates export/ wholesale
port/ the Godot 4 project
authored/ decisions that are not on the disc, each with its reason
export/ generated, gitignored, never hand-edited
tools/ verification harnesses that hold the port to the reference renderer
docs/ the mission, the format spec, the agent's loop prompt

Verifying

sylpheed-cli screen render -- built from the same sylpheed-formats revision the exporter is pinned to -- is the reference renderer. tools/verify-screen draws every exported screen both ways and reports the largest per-channel difference in the frame:

tools/verify-screen              # every screen in the manifest
tools/verify-screen main_menu    # one of them

Where the two disagree, one of them is wrong; docs/DECISIONS.md says which and why, rather than tuning the port until the number goes down.

Status

P1. The exporter writes GP_TITLE's twelve screen builds and their sprites, and the Godot project draws any of them statically at 1280x720 from that tree alone. main_menu matches the reference renderer to within 3/255 on every channel of every pixel. Next: P2, keyframe animation.

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