CORRECTION FIRST: I refuted the Decoder's by-size identification on the ground
that both sweep sprites are 399x180. Wrong -- I compared source PNGs and never
read the leaf scales, which are [100,600] and [100,800], so the DRAWN quads
differ by a third. That is exactly the 3.15 vs 3.62 NDC they were separating by.
Size distinguishes them fine. The hold was right, the check found a real defect,
but my stated reason did not survive.
Which sharpens the real lead: because size DOES separate them, 'pteff03a does not
appear in this capture at all' is well-evidenced. The port draws it -- confirmed
at t=120/180/240 -- on screen from t~108 to t~521, right-to-left at 800% scale,
inside the window the capture covers.
A second glow arriving at t~108 is a good candidate for 'the glow starts too
early'. One capture, one probe, identified by size: a lead, not a finding.
Also recorded a failed approach: isolating the sweeps by differencing --time
frames does not work, because during a build-in everything else is moving too.
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