Commit Graph
4 Commits
Author SHA1 Message Date
enricobuehler db15c2615d fix(vkdecode): HEVC decoded from the wrong references, and told drivers the
wrong slice offsets

Two independent defects, both in this crate. pf-bitstream is untouched — its
HEVC plans were sound all along, which the D3D11VA rung proves by rendering
correctly from the same AuPlans.

The corrupter: StdVideoDecodeH265PictureInfo's RefPicSetStCurrBefore,
StCurrAfter and LtCurr carry DPB SLOT indices. We wrote positions in the
reference list. libavcodec's Vulkan HEVC hwaccel — the implementation every
driver is validated against — writes the index into its own DPB array and
passes that same value as slotIndex, while packing pReferenceSlots densely
over the used entries; the two numberings are provably different there, and
the RPS arrays follow the slot.

The two readings coincide on a freshly anchored stream, because the references
then occupy slots 0..n in reference-list order. They first diverge at the
vendored vector's first B picture, AU 3, where refs are slots 0, 2, 1 — so we
named slots 1 and 2 where the picture wanted 2 and 1, and every later access
unit inherited the error through its own references. That is why this shipped
and why review could not see it: correct for the opening pictures, wrong from
the first reordering onward.

It also accounts for the measurements exactly. Display order maps to decode
order as display 0 from AU 0, display 3 from AU 1, display 2 from AU 2,
display 1 from AU 3 — so the three frames that matched on AMD are precisely
the three access units where positions and slots agree, and 250 - 3 = 247 is
the divergence count that was measured. From AU 6 the named slots stop being
merely wrong and become unbindable by that operation, which is where NVIDIA
stopped reporting a verdict at all.

The diagnostic: every slice offset must point at a THREE-byte start code.
libavcodec discards the stream's prefix and writes 00 00 01, so that is the
only pattern drivers are validated on, and pf-dxvadec's packer already
normalised for exactly this reason and said so in its docs. This path uploaded
the prefix verbatim. 249 of 250 HEVC slice segments in the vendored vector
carry a four-byte prefix; all 500 H.264 slices carry three.

That derives the driver's own complaint bit for bit. A decoder reaching the
slice header by a fixed skip lands on the NAL header's second byte, reads
first_slice_segment_in_pic_flag as 0, and then takes six bits of the real
slice header as the tail of a long ue(v): 0xd0 gives 115, 0xe0 gives 119. A
P-slice header and a B-slice header — which is why exactly two bogus pps_id
values ever appeared.

⚠ H.264 was NOT protected structurally, only by its encoder's convention, and
the real host does not share that convention: every one of 1514 H.264 access
units and 1133 HEVC access units captured from an NVENC host prefixes its
slices with FOUR bytes. The vendored H.264 vector is therefore not
representative of what ships, and its bit-exactness was passing on a prefix
form the field never sends. The normalisation lives in the shared ring layer
and covers both codecs for that reason.

rebased_offsets is replaced by pack_slices, which trims the leading zero byte
and computes the offsets from the trimmed lengths in one call, so the bytes and
the offsets cannot drift apart; upload and the CPU test go through the same
pack_into.

Hardware, after the fix — H.264 AND H.265 both 250/250 bit-identical to
libavcodec, all four smoke legs green:

  NVIDIA RTX 4090      610.88     Windows   coincide
  AMD Adrenalin        25.10.30.02 Windows  distinct
  NVIDIA RTX 5070 Ti   610.43.03  Linux     coincide

On glass on the 4090 against a real NVENC host, 2800x1260 HEVC through the
auto ladder: 73 one-second windows all native-vulkan, fps avg 59.3 of 60,
decode 1.1 ms, e2e 4.5 ms p50, and ZERO driver-reported status failures where
the same session before the fix logged 1489 in 181 seconds and had dragged ABR
down to a 5 Mb/s target. No refusals, demotions, PlanWarnings, concealment,
DEVICE_LOSTs or panics.

Both defects now have CPU tests that were confirmed FAILING before the fix:
one walks every access unit of both vendored vectors and asserts each declared
offset opens on a three-byte start code, its own NAL header and a
first_slice_segment_in_pic_flag consistent with the segment index; the other
resolves every RPS entry by slot and asserts that 247 access units disagree
with the positional reading, so it cannot go vacuous on a stream where the two
happen to agree.
2026-08-06 09:56:25 +02:00
enricobuehler 2a57ee36f8 feat(client): M4 — the decoder's own verdict reaches the session
This program exists because a field corruption was architecturally
undetectable through FFmpeg: no decode-status read, no corrupt-frame
flag, errors only as scraped log lines, and no recovery-point signal so
intra-refresh healing was invisible. The native decoder has all of those.
M4 is where they stop being internal.

DecodeHealth counts, per session and without allocating per frame, what
the three answers actually are: damaged (the stream arrived incomplete),
refused (the rung would not decode it at all) and driver-failed (the
hardware says it could not decode what arrived), plus the current and
worst concealment run — the figures that separate one bad AU from a
stream that never came back. They ride the stats line additively, so an
FFmpeg session and a healthy native session emit byte-identical output
to today. The status-query capability is reported too: without it a
clean report cannot be told from an unmeasured one, which is the whole
nb_queries=0 lesson.

The headline is local recovery. Until now the pump could only learn that
intra-refresh healing finished from wire flags the host sends; absent
those it froze until the 500 ms backstop forced an IDR. The parsed
recovery-point SEI now feeds the re-anchor gate directly, so a session
lifts on the picture that is actually clean. Wire semantics are
untouched for every client that never calls it.

Detection now asks for recovery instead of erroring — an integrity
warning ticking the error streak would demote the native rung on exactly
the lossy links it exists to diagnose, where an FFmpeg rung conceals
silently and keeps its job.

Review round 12 found that trade had removed the escape hatch entirely.
Concealment returning Ok(None) reset the demotion streak, and worse: the
driver-verdict ledger is only populated when a frame ships, so under
continuous concealment no verdict was ever read and the erroring arm
could not fire at all. A host framing regression of the 0.23.0
slice-wire class — which does not self-heal, and which a keyframe does
not clear — would have frozen indefinitely with no demotion and a clean
integrity line, where before it demoted to FFmpeg-Vulkan and showed a
picture. Now only an answer that proves the rung works clears the
streak: a shipped frame, or a clean no-frame. Concealment neither ticks
nor clears, so a lossy link still cannot demote a healthy rung while a
driver failure interleaved with concealment reaches the threshold again.

Two more honesty defects from the same round. A rung refusing every AU
reported no integrity line at all — the founding failure mode, wearing
the shape of a clean bill of health; refusals are now counted. And
driver-failed could be non-zero on a device that cannot produce driver
verdicts, because a degraded timeline read looked the same as one; the
attribution is now withheld inside the counter rather than at call
sites, so the self-contradictory line is unrepresentable.

Local recovery also no longer trusts any recovery-point SEI: only one
whose target advances past an outstanding wave counts as a new wave, so
an encoder re-announcing the current wave with a decreasing count — legal,
and what x264 intra-refresh does — cannot lift the freeze early onto a
partially stale picture. Frames buffered across an arm are dropped by
decode order for the same reason.

Fault injection is a first-class tool now (PUNKTFUNK_AU_FAULT, inert
unless set, env read once). Its test replays the vendored vectors
through the real planners and asserts a negative the plan assumed away:
truncation and bit flips are PROVABLY invisible to the parser — Annex-B
carries no NALU length, so a cut slice is just a shorter slice and a
flipped payload byte is syntactically perfect. Only dropped AUs are
parser-detectable; the rest need the driver verdict, which is why the
status query matters. The H.265 leg found a second: three of that
vector's faulted AUs are sub-layer non-reference pictures, so dropping
them damages nothing and silence is correct — the test asserts both
verdicts and guards that neither half goes vacuous.

Per-frame decode latency was deliberately NOT built. Polling answers
only 'complete by now', and the pump polls once per AU, so every sample
would quantise up by as much as a frame interval — 8.3 ms at 120 Hz
against decodes of 0.1-2 ms. Sampling faster needs a spin or a second
thread on a decoder that is deliberately not Sync. A blocking per-frame
wait is the field scar that once capped a stream at 51 fps. The honest
sampled stat stands.

Also fixed, pre-existing: the re-anchor gate re-armed on every damaged
AU, so sustained damage permanently zeroed the mark count — meaning the
wire's two-mark rule could never complete on exactly the lossy links it
was written for.

Field note recorded while wiring this: intra_refresh_recovery is set by
exactly one encoder backend (Linux libav-NVENC under
PUNKTFUNK_INTRA_REFRESH). AMF and QSV run a wave with no wire mark, and
AMF emits no recovery-point SEI either, so AMD/Windows intra-refresh
sessions still have no clean recovery point by either route.

Gates: fmt clean; container clippy -D warnings zero across
pf-client-core + pf-presenter + pf-vkdecode + punktfunk-core; tests
69/131/129/354/41 plus 5 fault-detection green; cargo check --workspace
clean.
2026-08-06 04:30:40 +02:00
enricobuehler e4d8573475 feat(client): the native rung now decodes HEVC as well as H.264
The last piece of M3 WP-2 — VkH265Decoder was built and hardware-gated
but nothing drove it. video_vk_native.rs holds a two-arm codec enum and
forwards to it; the ledger, release tokens, status-query settling and
timeline waits are byte-for-byte what they were, since they were always
codec-agnostic over one DecodedVkFrame contract. The forwarders are
written out per arm rather than macro'd so the unchanged H.264 arm is
visible to a reviewer.

The picture's own format now reaches the presenter, which picks bit
depth and MSB packing from it instead of assuming the H.264 envelope.
That incidentally fixes a live bug on the SHIPPING FFmpeg-Vulkan path:
it derived ten-bit-ness by comparing against the 10-bit 4:2:0 format
alone, so a 10-bit two-plane 4:4:4 surface — which its own format table
accepts, and which NVIDIA reports for HEVC RExt — got 8-bit range and
transfer maths. Reachable today with Full chroma plus 10-bit: decoded
correctly, displayed wrong.

Review round 11 caught a regression this WP would otherwise have
shipped. pf-vkdecode refuses a stream whose (chroma, depth) pair has no
picture format on the device, but the session is built lazily from the
first SPS, so the refusal arrived AFTER construction — past the point
where a native init failure falls through to FFmpeg-Vulkan. It burned
the error streak instead and demoted to VAAPI/D3D11VA, which on
NVIDIA/Linux means software. Turning on Full chroma on any non-NVIDIA
GPU was enough: a 4K HEVC session that ran on FFmpeg-Vulkan before this
branch would have landed on software decode.

Both halves are fixed. The negotiated chroma and bit depth — already at
the call site, the PyroWave arm four lines up uses them — are threaded
into the backend, which probes the same caps path ensure_state would
run, so the whole class refuses at CONSTRUCTION where the fall-through
already exists. For the legs no negotiation can carry (a level above
maxLevelIdc, an SPS that disagrees with the Welcome) the decoder latches
'never delivered a frame' and routes that first streak to FFmpeg-Vulkan
rather than down the hardware ladder. H.264 is deliberately not probed:
its envelope is fixed, so a probe would only add a profile guess on the
bit-exact path; it gets the latch as its backstop.

Two more from the round. Planner warnings are typed again rather than
Debug strings — pf-vkdecode simply lacked the h265 re-export its h264
twin already had — which restores the H.264 log rendering exactly and
unblocks M4, whose job is counting concealment by kind. And concealment
is now the integrity set only: NonZeroReorder is documented spec-legal
and fully planned, but the client treated every warning as damage, so
the opening IDR and every ABR renegotiation's IDR were released unshown
and re-anchored — a visible hitch on a healthy stream.

Also: a raw-format newtype so a neighbouring i32 field cannot be passed
to the colour maths, the presenter's depth table now pinned against
pf-vkdecode's actual output vocabulary rather than the FFmpeg lane's,
a per-format warn latch, and four stale docs.

Gates: fmt clean; container clippy -D warnings zero across
pf-client-core + pf-presenter + pf-vkdecode; tests 69/125/108/40 green;
cargo check --workspace clean.
2026-08-06 03:02:09 +02:00
enricobuehler 6d8f3b45b5 feat(pf-vkdecode): the GPU half of HEVC decode — session, pools, recording
M3 WP-2 complete. caps_h265.rs builds the profile the stream actually
needs (profile idc + chroma + bit depths, all three stated on every
Vulkan object) and resolves its picture format — Main to NV12, Main 10
to P010, RExt 4:4:4 to the two-plane 4:4:4 formats — validating it
against the format list of every role the chosen arrangement creates
images in. A Main 10 stream on an 8-bit-only device is refused BEFORE a
session exists, never narrowed: decoding 10-bit into an 8-bit surface is
the silent-wrongness class this crate exists to refuse. session_h265.rs
adds the three-array parameters ledger; decoder_h265.rs adds
VkH265Decoder, mirroring VkH264Decoder method-for-method so the client
wiring is a two-arm dispatch away.

H.264 and H.265 now SHARE the machinery instead of duplicating it:
derive_arrangement (one coincide/distinct/layered decision table),
ring::rebased_offsets (the slices-only rebase — non-VCL NALUs in the
decode range hang VCN firmware), session::bind_session_memory, and a
parameterised build_frame. A DecodeProfile enum replaces the bare
profile idc that images.rs and ring.rs used to take: both codecs' idc
types are c_uint, so handing an H.265 idc to the H.264 path COMPILED
SILENTLY and built a mismatched profile chain. That is now
unrepresentable.

The VPS leg is the ledger's real work. The vendored parser attaches a
VPS to an SPS only when it saw the NALU, and clients join live streams,
so VpsSource is Parsed-or-FromSps and is stored BY VALUE: re-activating
a VPS-less SPS is Current (no churn), but the real VPS arriving under
the same id is a content change and RECREATES onto it, because Vulkan
cannot replace a stored parameter set.

Review round 10 (adversarial) confirmed the hardware-proven H.264 path
is NOT regressed — derive_arrangement's check order and error identity
are byte-for-byte the original, build_frame's call sites still pass the
granularity-aligned extent (the 1088-row scar stays shut), and
rebased_offsets reproduces the deleted inline loop for every input while
moving the sum to u64 so overflow errors instead of wrapping. Also
verified: the refs-order contract on every path, the RESULT_STATUS caps
gate (each of reset/begin/end individually gated, no pool created when
unsupported — recording one on RADV hangs its VCN), pNext lifetimes, and
that no panic is reachable on stream input.

Its 10 findings are fixed. The two that mattered:

- A failed decode stranded a DPB slot. Once plan_to_vk_h265 had mutated
  the slot map, five later failure paths returned without restoring it,
  so planner and slot map both believed a picture was resident while no
  image held it — and every later AU referencing it failed, where H.264
  soft-degrades and keeps delivering. Fail-closed is kept (substituting
  a reference silently is the corruption-hiding this program exists to
  end) but made RECOVERABLE: a latch flushes the planner to AwaitingIdr
  and resets the bindings on the next decode, which composes with the
  client already requesting a keyframe on every decode error. The fix
  deliberately covers pre-mutation failures too — those strand the
  picture the other way round and wedge identically.
- DecodedVkFrame carried no picture format, so a Main 10 frame would
  decode correctly and be rendered with 8-bit transfer/range math. It
  now carries one, stamped from the pool so it is truthful for both
  decoders by construction. The presenter comment says depth 8 is
  because only H.264 is WIRED, not a decoder limit.

Plus: bind_session_memory freed allocations before the session that may
hold them was destroyed (an ordering regression from the extraction,
with a SAFETY comment asserting the opposite) — the bind-stage exit now
hands them back so Drop destroys first; max_level_idc is codec-tagged
rather than an H.264 type carrying H.265 code points; and the decode
family's videoCodecOperations is now checked, turning 'create an H.265
session on a device without the extension' from UB into a clean ladder
demote.

Deferred by design: no HEVC gpu_smoke/gpu_parity yet (its goldens are
already in tests/data/test-25fps-h265.nv12.sha256), and no codec
dispatch in the client — both later legs.

Gates: fmt clean; mac clippy zero warnings, pf-vkdecode 106 +
pf-bitstream 69 green; container clippy -D warnings zero for
pf-client-core + pf-presenter + pf-vkdecode, tests 69/121/106 green.

HARDWARE (.173, after the refactor — review saying the proven path is
safe is not the GPU saying it): gpu_parity '250 frames bit-identical to
libavcodec software decode' on BOTH the NVIDIA 4090 (610.88, coincide
mode) and the AMD iGPU (Adrenalin 25.10.30.02, distinct mode), gpu_smoke
green on both. Two independent drivers, both DPB modes, still bit-exact.
The smoke trace also shows the new videoCodecOperations capture reading
DECODE_H264 | DECODE_H265 | DECODE_AV1 off the real decode family.
2026-08-06 01:59:39 +02:00