The SYSTEM host now sources the normal-desktop video from a user-session WGC
helper instead of capturing in-process (WGC won't activate as SYSTEM). New
`capture/wgc_relay.rs`: `HelperRelay::spawn` launches `m3-host wgc-helper` in the
interactive user session via CreateProcessAsUserW (WTSQueryUserToken →
DuplicateTokenEx(TokenPrimary) → lpDesktop="winsta0\\default", CREATE_NO_WINDOW)
with three anonymous pipes — stdout (framed Annex-B AUs → parsed back to
RelayAu), stdin (control: force-keyframe), stderr (helper logs → host tracing).
The host holds the SudoVDA keepalive (sole isolation/topology owner); the helper
captures by GDI name only.
m3.rs: `virtual_stream` dispatches to the new `virtual_stream_relay` when
`should_use_helper()` (running as SYSTEM, or PUNKTFUNK_FORCE_HELPER; disable with
PUNKTFUNK_NO_HELPER). The relay loop feeds the existing send thread — same
FEC/seal/paced-send path. Reconfigure rebuilds the output + re-spawns the helper;
keyframe requests forward over the control pipe; helper pts_ns (same-machine
monotonic clock) is used directly as capture_ns. Disconnect ends the stream
(step 6 adds the relaunch watchdog).
wgc_helper.rs: reads the stdin control byte to request an IDR; --bit-depth flag
threaded through so SDR 10-bit (Main10) negotiation reaches the helper's encoder.
cfg-gated windows-only; Linux/macOS build unaffected. Step 5 (DesktopWatcher mux
to host DDA on the Winlogon secure desktop) is next.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
enricobuehler
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