forked from unom/punktfunk
WP-D parity A/B. gpu_parity (ignored) decodes the conformance vector, reads every frame back through the presenter's exact contract (wait, layout round-trip, signal-back, release), crops at the copy so pitch can never leak, and compares SHA-256s in display order against goldens from ffmpeg software decode — cross-checked bit-identical between ffmpeg 8.0.1 (linux) and 8.1.1 (macOS), so the reference is the spec, not one build. PF_VKD_TEST_READBACK=1 is the one test-only hook (ORs TRANSFER_SRC into pool usage; production pools stay zero-copy-tight). Fleet verdict: 250/250 frames bit-identical to libavcodec on RADV (Mesa 26.0.3, distinct), AMD proprietary Windows (25.10.30.02, distinct) and NVIDIA Windows (610.88, coincide) — H.264 decode is exactly specified, and the native path meets the spec on every driver and both DPB arrangements.