Files
Sylpheed/docs/re/data/decoder-eras-all-16-builds.txt
sylph-decoder 82ce9dbaaa re: the decoder eras DO change pixels -- 7 of 16 bundles, and title_jp is one
The reach test I deferred twice. sylpheed-port tested three screens across the
stale and fixed ui_layout.rs eras, found 0 differing pixels, and concluded the
eras explain nothing. Built both eras from source and rendered EVERY composable
GP_TITLE bundle through each.

7 of 16 differ. Entries 0-6, 8 and 9 are byte-identical -- which includes title
(4), main_menu (5) and extras (6), so the port's result reproduces for the
screens they picked. Entry 7 (title_jp) differs by 74 507 px, RMSE 12.409; the
two loading bundles by 49 771 px, RMSE 10.078; the four splashes by 23-33k px at
RMSE 0.94-1.78.

So "the eras explain nothing" is true for three screens and false for the
archive. It is specifically false for title_jp, which is one of the two rows
their check-all now allows BY NAME with the reason "rest-pose sparkles". Their
measurement of that screen was 0 and mine is 74 507; recorded with exact flags as
a disagreement for them to check, not adjudicated. Noted that their branch's
ui_layout.rs is the stale one (20 ins / 488 del against the pin), so a binary
built from their workspace HEAD is the stale era.

Two controls, both run first. The binaries genuinely embody the eras: build 5's
pteff00.prm reads `rest t=70 [12 70 80 -]` stale against `rest t=12 [0 12 70 80]`
fixed. And the renderer is deterministic: same binary, same flags, twice, 0
differing pixels on entries 7 and 12 -- without which every number is noise.

Mechanism on entry 7 is a single element, ptlogo_eff3.t32, rest (108,72) ->
(98,42). That is the element MISSION.md and ui-resting-pose.md already name as
THE plateau-less rest() discriminator, so the era difference on the JP title is
our existing open question surfacing rather than a new one.

And a trap: entries 10-15 differ by up to 49 771 px with NO rest position change.
The rest selection moves to a keyframe at the same (x,y) with a different scale
and alpha. My first extraction compared only the rest (x,y) column and would have
reported a difference with no cause. A pose is position and scale and alpha.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Wuu56cE8vJGTBtn1ppsk8v
2026-08-30 14:42:29 +00:00

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