CreateProcessAsUserW gives the spawned helper the *user's* environment block, so
the host's PUNKTFUNK_ENCODER=nvenc (and ZEROCOPY/PERF/…) were dropped and the
helper fell back to the software (H.264-only) encoder — the client negotiated
H265 → "WGC helper exited". `merged_env_block` now parses the user block, strips
any PUNKTFUNK_* it carried, overlays this (host) process's PUNKTFUNK_* vars, and
passes the merged UTF-16 block.
Validated live on the RTX 4090 (host as SYSTEM): the helper spawns via
CreateProcessAsUserW, runs WGC with no hang (HDR FP16 BT.2020 PQ), opens NVENC
(D3D11 Main10), and relays AUs over the pipe — client-rs decoded 411 HEVC
Main-10 frames over the LAN. Step 4 (spawn + relay) complete.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
enricobuehler
8d6cbb81fe