forked from unom/punktfunk
enricobuehler
31087697a9
The Windows fallback rung, and auto's first choice on Intel, now has a native implementation driven by pf-bitstream's plans instead of libavcodec. New crate pf-dxvadec holds everything that can be a pure function — the DXVA structure layouts, both codec conversions, bitstream packing, config selection — deliberately CROSS-PLATFORM, because a cfg(windows) module is verified by a remote cargo check and nothing else, and this milestone's riskiest code is exactly the part no local test can see. Only the FFI lives in video_d3d11_native.rs. windows-rs does not generate dxva.h at the pinned rev, so the DXVA structures are hand-declared: compile-time assertions on every struct size AND every field offset, packed bitfield words as plain integers with named builders and the bit positions written beside the C declaration, and a const zeroed() per struct so construction needs no unsafe at all. The crate's only unsafe is a sealed byte view over those PODs. Review round 13 checked all seven layouts field by field in declaration order — sizes, widths, array lengths, the PicEntry index/flag packing, and every named bit's position and width. The decode pool reproduces libavcodec's rather than inventing one: ONE texture with ArraySize = pool size, BIND_DECODER and nothing else, MiscFlags 0, aligned 16 for H.264 and 128 for HEVC. That is deliberate. This rung's predecessor records that a hand-built pool which validated on NVIDIA was rejected by Intel at the first SubmitDecoderBuffers — and Intel is the vendor this rung exists for. The VideoProcessorBlt into shareable RGBA is untouched: importing a multiplanar NV12 D3D11 texture into Vulkan device-losts on NVIDIA, so that hand-off is load-bearing field-proven code. It was extracted into a shared HandoffRing so both rungs fill one implementation; the review diffed the blit statement by statement, including the keyed-mutex pairing. Review round 13's four defects are fixed. The blocking one: the HEVC quantisation matrix was submitted unconditionally, and the vendored parser leaves it ALL ZEROS unless the stream codes one — unlike FFmpeg, which seeds the spec defaults. On a stream saying 'use the default matrices' the driver is obliged to apply what it is handed, so every residual would dequantise to zero and the picture would drift to flat prediction. It is now gated on scaling_list_enabled_flag exactly as libav gates it, with the Table 7-5/7-6 defaults supplied when enabled but uncoded. Second: NumMBsInBuffer was 0 where libav's H.264 path sets mb_width * mb_height. This module's whole method is verbatim reproduction on precisely the call that once failed for Intel, so an omitted descriptor field is the same class of bug as the pool. Third, and the one to watch on hardware: RefFrameList carried the frame's reference set rather than the pictures marked used for reference. Vulkan defines pReferenceSlots as the slots this operation uses, so a subset is correct there; DXVA defines RefFrameList as a statement about the DPB. The list DERIVATION survives a subset — which is exactly why a smoke test would have passed — but a long-term reference held across frames that none of them name would vanish and reappear, and a driver keeping per-reference state is entitled to discard it in between. That is the Ally X symptom shape. pf-bitstream now exposes a per-AU DPB snapshot for both codecs and the converters build the array from it, frame references first, marked tail appended. 121 of the 250 vendored AUs carry a marked picture the frame never names, so this is exercised, not theoretical. Fourth: the session identity omitted bit depth and chroma, while the Windows host flips an HDR desktop to PQ in-band with a new SPS — a depth change at unchanged size would have decoded 10-bit samples into an NV12 pool. Identity now derives from the SPS per AU and rebuilds. Wired PIN-ONLY (PUNKTFUNK_DECODER=native-d3d11va), absent from every auto arm. Nothing has decoded a frame yet, and M2's discipline was that auto admission comes only after hardware parity. A runtime streak demotes to the FFmpeg D3D11VA rung first, then software. Also scaffolded: a byte-diff harness against libavcodec's own DXVA picture parameters, with the FFmpeg patch and capture recipe in its docs. Nothing here is checked against libav's actual bytes the way M3 was checked against its pixels, and that is the cheap way to buy the confidence before hardware. Gates: fmt clean; container clippy -D warnings zero across pf-client-core + pf-presenter + pf-vkdecode + pf-dxvadec + punktfunk-core; tests 73/131/63/129/354 green; cargo check --workspace clean; Windows cargo check and clippy -D warnings clean on .173.