Four findings, all real.
**`SlotMap`'s own docs had become false.** "feed it every `DpbUpdate` in decode order
(via `Self::apply` or `plan_to_vk`, which applies internally)" — `plan_to_vk` no longer
applies internally, which is the entire point of the change, and `release`'s docs named
it as one of the two things that may free a slot. A reader following those docs would
build the next caller wrong in exactly the way this commit's parent fixed. Both now say
which conversions defer, which one does not, and why H.265 is the one that does not.
**The deferred release warned on a legitimate event.** `release_deferred` warned per id
when a deferred release found no slot — but a renegotiation replaces the whole
`Session`, and with it the slot map, INSIDE `plan`, while the planner's own drain
reports every drained picture in that same access unit's `removed`. Every one of those
ids then misses, and nothing is wrong. `debug!`, with the legitimate cause named so the
illegitimate one stays diagnosable.
**HEVC's exemption was asserted only in its consequence.** `the_current_picture_is_
named_by_curr_pic_and_never_aliases_a_reference` checked that no reference shares the
decode target's slot — which on the vendored vector holds whether or not the reasoning
behind it does. That is precisely how the H.264 leg passed for two milestones. The test
now also asserts the PLANNER property the exemption rests on (`removed ∩ dpb_refs = ∅`,
falsified by moving `dpb_snapshot()` above `decode_rps`), and records that the low-delay
measurement was 0 of 300 against H.264's 297 of 300 from the same host and the same run.
It also records what is still missing: no low-delay HEVC stream is vendored, so HEVC's
freedom is a re-derivable argument plus one measurement, not a standing hardware leg.
**Two stale cross-references.** Both AV1 conversions told the reader the H.264/H.265
zero was "measured on reordering vectors and not a proof" — the open question this
commit's parent closed. They now say what the answer was.
enricobuehler
fd6241a24f