During my time playing VRChat, I discovered that the webcam face tracking feature was not working. The symptoms indicated that while the device could be detected, it could not be accessed; an error message stated “webcam incompatible or in use with another app,” and the camera activity light remained off. By capturing logs and analyzing them with AI, I gradually pinpointed the issue: the system required the RGB32 video format, but it could not be provided. With the assistance of AI (providing both the conceptual approach and sample code), I implemented modifications to the Smart Tee filter’s allocator and RGB32 negotiation, and further fixed the V4L backend’s WoW64 media type marshalling. Afterward, I manually tested the relevant modifications on Windows 11 to align the behavior between the two environments. I then used the patched Wine to test the previously problematic AMCap, extracted the patch, and built a custom GE-Proton. I verified that the VRChat webcam face tracking feature now works correctly. This patch should alleviate similar failures encountered by DirectShow-based applications in Wine environments when initializing or previewing webcam streams. -- https://gitlab.winehq.org/wine/wine/-/merge_requests/10377