Remove DXGI Desktop Duplication (DuplCapturer), Windows.Graphics.Capture
(WgcCapturer), the two-process SYSTEM+helper relay (virtual_stream_relay /
HelperRelay / DesktopWatcher / composed_flip), and the five source files that
implemented them. IDD direct-push is now the sole Windows capture path; the
session topology is always SingleProcess.
Deleted files: wgc.rs, wgc_relay.rs, desktop_watch.rs, composed_flip.rs,
windows/wgc_helper.rs (+ wgc-helper subcommand in main.rs).
dxgi.rs is kept but carved to shared GPU primitives only (make_device,
HdrP010Converter, VideoConverter, install_gpu_pref_hook, WinCaptureTarget,
pack_luid) — ~2237 lines of DDA-only code removed; imports cleaned.
capture.rs: IDD-push open failure fails the session cleanly (no fallback).
Adds capturer_supports_444() — returns false on Windows (IDD-push 4:4:4 is a
follow-up), replacing the stale single_process gate in 4:4:4 negotiation.
session_plan.rs: CaptureBackend{Dda,Wgc} and SessionTopology::TwoProcessRelay
removed. config.rs: no_helper/force_helper/no_wgc/capture_backend/secure_dda
removed. merged_env_block relocated from wgc_relay to windows/interactive.rs.
Linux cargo check clean.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
enricobuehler
b9c8d5ab43