Wave-2 PW5 stage 3. Depth is STILL 1; this is the shape change alone.
`encode_frame` recorded CSC+encode, queue-submitted, waited the fence and packetized, all inside
`Encoder::submit`. Every other backend in this crate puts the wait on the POLL side. That
difference is the whole reason the host loop's cadence folds around this encoder: with the wait
inline, `submit` returns only after the GPU is done, so the arrival-anchored floor absorbs the
encode only while it stays under 0.9x the frame interval.
Split into `submit_frame` (ingest -> CSC -> pyrowave encode -> queue-submit -> return) and
`wait_and_packetize` (fence wait -> packetize -> AU), with an `InFlight` deque between them capped
by `max_inflight`, which is 1. **One is the only value the resources can support today** — `cmd`,
`fence`, `csc_set` and the y/uv images are one each, so a second concurrent frame would record into
a PENDING command buffer and storage-write images pyrowave is still sampling. `submit` therefore
drains to `max_inflight - 1` before recording, which states that invariant in one place instead of
leaving it implicit in "the encode is synchronous".
The subtle part is the command-buffer state machine, and it is unchanged: the record-and-submit
closure still resets `cmd` on every PRE-submit failure (RECORDING/INVALID/EXECUTABLE, never
PENDING), and the fence wait still does NOT reset on failure, because a timeout leaves the buffer
PENDING where a reset violates VUID-vkResetCommandBuffer-commandBuffer-00045. What changed is that
a failed wait now also leaves the entry IN FLIGHT — which is precisely what tells `reset()` there
is live GPU work to re-wait before the pyrowave encoder object may be destroyed. `gpu_pending` is
gone; `!inflight.is_empty()` is the same fact, and cannot drift from it.
The split opened two windows that did not exist when everything ran inline, both closed here:
`reconfigure_bitrate` and `set_wire_chunking` can now land BETWEEN a submit and its poll, so the
packetize boundary and the bitstream cap are snapshotted into `InFlight` at submit time. Reading
the live fields would have let a mid-flight bitrate drop turn a perfectly good frame into
"unexpected packet count", and a mid-flight chunking change into an AU with the wrong
`chunk_aligned` flag.
`flush()` is no longer a no-op — it drains the in-flight frame, so the trait's poll-until-None
contract still returns every AU (the `spike` subcommand and the hardware smoke tests are the real
users).
The perf instrument still measures submit->AU, stamped at submit and taken when the AU becomes
readable, so `92326312`'s numbers stay directly comparable; the log line now carries `depth` and
says plainly that above depth 1 the number legitimately grows by about one loop period.
VERIFIED ON GLASS (.21, RTX 5070 Ti, GPU idle at 180 MHz of 3090 — so these are slow-clock runs,
which is the worst case on this card, not the best): all 6 `#[ignore]`d GPU tests pass — the
4:2:0, 4:4:4 and 24-bpp PSNR smokes, the mode-mismatch refusal, the fd-leak check and the golden
dump.
Byte-identity, honestly: the AU bytes are NOT reproducible, and were not before this commit
either. Three runs of the SAME unmodified binary produced three different `au-dense.bin` hashes
(ab7ecaf6 / 8735700e / 933b3d40) — the vendored 4:2:0 encoder emits run-varying bytes that the
decoder ignores. So the meaningful gate is DECODE identity, and that holds exactly: every decoded
plane (`ref-dense-{y,cb,cr}`, `ref-chunked-{y,cb,cr}`, `ref-dense444-{y,cb,cr}`) is bit-identical
between the pre-split base and this commit, across four runs. 4:4:4 AUs are additionally
bit-stable and match the checked-in Apple fixture exactly.
Gates green at CI parity.
enricobuehler
95962f55d0