## Summary This work started from a real-world regression: in VRChat, the camera could not be used. After investigation, VRChat was found to use DirectShow for camera capture/preview. The issue was then narrowed down to qcap behavior differences, and fixes were implemented in source code to align with native behavior. This MR includes: 1. Smart Tee preview RGB32 negotiation fix. 2. V4L wow64 media type marshaling fix. These changes are expected to resolve this class of DirectShow camera compatibility issues. ## Root cause and approach - Application symptom: VRChat camera path failed. - API path: DirectShow camera pipeline. - Scope narrowed to qcap Smart Tee preview negotiation and wow64 media-type marshaling in V4L backend. - Implemented behavior-aligned fixes and corresponding conformance tests. ## Validation - Native Windows behavior was probed and used as baseline during test alignment. - `qcap_test.exe smartteefilter`: **488 tests, 0 failures** (i386/x86_64) - `qcap_test.exe videocapture`: **754 tests, 0 failures** (i386/x86_64) - Functional app check: `AMCap.exe` preview opens camera successfully and image display is normal. ## Expected impact This MR is expected to fix/mitigate similar cases where DirectShow-based applications fail to initialize or preview camera streams under Wine. -- https://gitlab.winehq.org/wine/wine/-/merge_requests/10269