forked from unom/punktfunk
2026-07-12 review of the host encoders / client decoders / RFI plane. NVENC (both), AMF-LTR, the session glue, and the client RfiTracker came out clean; every fix lands in the Vulkan Video backend + dispatch: 1. HEVC: author each P-frame's short-term RPS to retain ALL resident DPB pictures (minus the setup slot), not just its one reference. HEVC 8.3.2 evicts unlisted pictures, and clients keep FEEDING the decoder while frozen — so with the old single-pic RPS, a conforming parser (FFmpeg = the Linux VAAPI/Vulkan and Windows D3D11VA clients) had already discarded the picture an RFI recovery anchor references whenever a fed post-loss frame preceded it: generate_missing_ref, and the "clean" anchor plus everything chained after it decodes as garbage. Pure builder (`build_h265_rps_s0`) + unit tests; AV1 needs nothing (slot-based retention). The smoke test now encodes a fed post-loss frame between loss@4 and anchor@6 so an ffmpeg decode of the dropped dump exercises exactly this (expect ONE POC-4 complaint, never POC 3) — revalidate on the AMD box; this NVIDIA dev box fails the backend earlier at HEVC header retrieval (pre-existing). 2. AV1: chain PhysicalDeviceVideoEncodeAV1FeaturesKHR (videoEncodeAV1 = TRUE, stype 1000513004) into device creation — spec-required for the ENCODE_AV1 codec op; RADV tolerated the omission, validation layers and stricter drivers do not. 3. RFI decline no longer self-arms force_kf — that bypassed the session glue's 750 ms IDR cooldown, turning a storm of hopeless RFI requests into one full IDR each. Decline like NVENC/AMF and let the caller's coalesced keyframe path own the fallback; add the missing first>last guard for parity. 4. open_video_backend now returns the label of the branch that ACTUALLY opened, so the mgmt API / web console reports "vulkan" instead of "vaapi" for the default-on Vulkan sessions (the old dispatch-mirror resolved_backend_label went stale when the backend gained its VAAPI fallback; deleted). Structure: the ~230-line inline HEVC coding block moves to record_coding_h265 (symmetric with record_coding_av1) and the duplicated pre-encode barriers dedupe into begin_encode_cmd. Follow-up plan (separate, punktfunk-planning): bring the post-loss freeze + RECOVERY_ANCHOR/POINT lift to the Android/Windows/Apple clients via a shared ReanchorGate (design/client-reanchor-freeze-parity.md). Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>