design/latency-reduction-2026-07.md tier 2, the two code-side halves:
- T2.2: the Linux direct-NVENC backend gains the two-thread retrieve
(PUNKTFUNK_NVENC_ASYNC, the same opt-in knob as Windows): the session stays
sync-mode (async events are Windows-only) but the blocking lock_bitstream
moves to a dedicated pf-nvenc-out thread — the NVENC guide's sanctioned
submit-thread/output-thread split. poll() drains completions non-blocking,
submit() backpressures at PUNKTFUNK_NVENC_ASYNC_DEPTH (default 4) in-flight;
map/unmap and every other session call stay on the encode thread; teardown
joins the thread before destroying the session. Under a GPU-saturating game
completed frames queue instead of serializing capture on the encode wait.
- T2.3: PUNKTFUNK_GPU_PRIORITY_CLASS gains 'auto' AND IT IS THE NEW DEFAULT
(gpu-contention §5.C): HIGH immediately, then REALTIME where the documented
NVIDIA+HAGS+near-full-VRAM NVENC hang cannot bite — HAGS probed once via
D3DKMT WDDM_2_7_CAPS (off => REALTIME outright); HAGS on => a pf-gpu-prio
monitor flips REALTIME<->HIGH on LOCAL-segment VRAM headroom (downgrade
>92% of budget, restore <=85% for 3x2s polls). 'high' restores the old
static default; 'realtime' pins it (operator owns the hazard).
Validated: .21 clippy -D warnings (punktfunk-host --features nvenc) against
the QSV-merged main; .133 Windows cargo check of pf-frame + punktfunk-host.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
encode.rs + encode/* (NVENC, VAAPI, native AMF, AMF/QSV ffmpeg, direct-SDK
NVENC/CUDA, raw Vulkan-Video, PyroWave, openh264) move into crates/pf-encode
behind one Encoder trait + open_video selector (plan §W6). The crate speaks the
shared frame vocabulary (pf-frame: CapturedFrame/PixelFormat + the DXGI identity
D3d11Frame/make_device) and pf-zerocopy (CUDA context/buffers), and NEVER
pf-capture — the capture→encode edge is one-way (ZeroCopyPolicy, prior commit).
Dep moves: the heavy encoder deps (ffmpeg-next, the NVENC SDK, openh264,
pyrowave-sys) move from the host to pf-encode; the host's
nvenc/amf-qsv/vulkan-encode/pyrowave features now FORWARD to pf-encode/*. The
host keeps a mod-encode shim (pub use pf_encode) so every crate::encode::* path
(negotiator + GameStream/native/mgmt planes) is unchanged.
resolve_render_adapter_luid moves from the host's windows/win_adapter.rs into
pf-gpu (both pf-encode and pf-capture need it as a peer of GPU selection); its 5
call sites (encode amf/nvenc, capture idd_push/synthetic_nv12, vdisplay manager)
rewire to pf_gpu::resolve_render_adapter_luid and win_adapter.rs is deleted.
pf-frame's make_device gains a # Safety section (public-unsafe-fn lint, latent
since the pf-frame carve — a full-workspace -D warnings clippy catches it).
Verified: Linux clippy -D warnings (pf-encode + host nvenc,vulkan-encode,pyrowave
--all-targets) + 13/13 pf-encode + 299/299 host tests; Windows clippy -D warnings
(pf-encode nvenc,amf-qsv --all-targets + host nvenc,amf-qsv --all-targets)
Finished exit 0.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
enricobuehler