Sample PGS across the title instead of reading its head

The content-based forced-subtitle probe spent its whole 256 MiB budget
on the first sectors of a title. A feature's subtitles begin minutes in,
so the probe read the opening logos, hit the budget, observed no display
set at all and contributed nothing to any verdict — the vendor label was
always the only input.

The forced predicate is asymmetric: one non-forced display set disproves
forced permanently, while proving forced needs the whole track, and
genuine forced tracks are tiny where full tracks are huge. So the same
budget is now SPREAD over each extent in ~16 MiB windows placed on the
AACS unit grid, sized in proportion to the extent, ending at the extent's
end. Cost is unchanged; placement is not.

Also:

  * Per-track early exit. A track that is disproven (and whose label
    needs no correcting) stops asking for budget; an extent that owes
    evidence only for such tracks is skipped outright, and evidence
    already in the cache is never demuxed a second time.

  * Content may now DEMOTE a wrong vendor forced flag, in the probe and
    in the muxer, behind one shared guard: absence of forced_on_flag
    only means something if some other track demonstrably uses it, and
    the track must have the shape of a full dialogue track rather than
    of a forced-narrative one. On a disc where no track sets the flag,
    nothing is demotable.

  * A sampled or budget-cut extent's evidence is memoised with the
    COVERAGE behind it. It used to be filed under the extent's full key
    and replayed to playlists that would have read far more of the clip,
    turning a prefix into an absence claim about the whole extent.

This commit is contained in:

Matthew Jackson

2026-08-02 16:07:02 -07:00

parent f53abfe0d4

commit 8ffce6b621

3 changed files with 1435 additions and 202 deletions

src/disc/pgs_forced_probe.rs

+1078 -190

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