As far I know, not directly with Xojo. To access webcam, I’m using opencv binding I wrote for Xojo (https://github.com/ldci/OpenCV-Xojo) which is running perfectly with OSX and Windows. Xojo for Linux is more problematic:)
i’m right in the middle of doing this on windows, I used the MBS plugin and had it running in about an hour.
the directshow classes are windows only though, so i don’t know bout Linux.