M2 WP-B. VkVideoSessionKHR lifecycle with drain-before-destroy on
parameters recreation, DPB pools in both coincide and distinct modes
(caps-derived, usage/flags validated against the driver's format
properties), an aligned bitstream ring, vkCmdDecodeVideoKHR recording
with one-shot RESET re-armed on failed submits, timeline-semaphore
completion, and the per-op RESULT_STATUS query ring — the signal
FFmpeg's hwaccel never reads and the reason this program exists.
Frame lifetime is two-phase by construction: release_frame pins a
delivered frame's slot against reuse, closing the coincide-mode
overwrite the adversarial review round proved (a full DPB handed a
just-returned frame's image back as the same call's decode target).
Nine review findings fixed pre-commit; a counterfactual test pins the
collision. Generation-stamped frames, memory-type misses as errors,
granularity-aligned extents, level gate.
AuPlan now carries its activated SPS/PPS (Rc) so backends never
re-parse. GPU smoke test (ignored) decodes 48 AUs past DPB-full with
releases — the fleet runs it in WP-D.
Gates: fmt clean, clippy -D warnings zero, 45+27+53 tests green on
macOS and the linux/amd64 container.