The splash rows have no free-running element, so their residual is chaseable
without a phase term. It is not tonal: max 255 with 0.012-0.017% of pixels over
8/255, in opposite directions on the two screens. That is the edge-antialiasing
signature.
Tested against an edge mask from the capture, with coverage checked first because
an earlier attempt on title failed by classifying 92% of the frame as edge:
publisher_logo mask 0.67%, residual 18.30 on edges against 1.42 off;
developer_logos mask 1.44%, 12.66 against 0.82. Non-degenerate masks, 13-15x
concentration. The 1.92 whole-frame floor is glyph-edge antialiasing.
Off the edges the port matches the game at 0.82-1.42 RMSE -- the cleanest
port-versus-game statement in the corpus, and confirmation of verify-capture's
long-standing note that the port is +9 to +12 on sprite edges, measured rather
than observed in passing.
Not everything is explained: 0.82-1.42 is still 15-25x the rasterisation floor,
consistent with the binned tone table leaving about a level of error, but not
shown to be that.
Also records the contamination check after their withdrawal of the A result:
nothing in authored/, docs/port/ or port/ cites it or the '2 of 2' run count.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01N7FiFFFwbvG2uxdcEh8HyF
b492a639d1