ContainerKind {Ts,Ps} + ClipLayout.container thread the post-decrypt structural check per clip; decryptability() dispatches it (TS: unit_is_clean_ts, PS: unit_is_clean_ps). New decrypt_unit_checked(unit,key,accept) decouples the container-agnostic AACS crypto from the format-specific acceptance (decrypt_unit delegates with the TS check). unit_is_clean_ps is the MPEG-2 PS pack-start check, documented UNVALIDATED for HD-DVD (.evo unit/seed/pack alignment must be confirmed on real media). clip_layouts assigns Ts today; .evo->Ps is the one-line HD-DVD hook.
reverify_iso now takes an is_finished predicate and SKIPS any unit with a non-Finished backing sector: we can't verify what wasn't read (a non-Finished sector is zero-filled because the drive read failed there), and must never waste a key lookup on a block the read already knows is bad. observe() (sweep) was already safe (only fed Good bytes).