Hello

Gem has a vlc plug-in that allows you to get video read by VLC into Gem (see pix_video help file)

Another option in linux (maybe also raspberry pi os) would be to set up a virtual v4l2 device with https://github.com/v4l2loopback/v4l2loopback/ then read the video stream with ffmpeg which is capable of writing it to the v4l2device https://github.com/v4l2loopback/v4l2loopback/wiki/FFmpeg and Gem then consider this virtual v4l2 device as a webcam (you have to say to pix_video which /dev/videoXXX it has to consider)

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Hello,
we had good results under linux with Microsoft LifeCam Studio 1080p HD and also with the cheap Hauppauge USB-Live-2 to capture PAL/NTSC signal or the deckling blackmagic devices for HD capture, devices which are not v4l2 but can be piped with v4l2loopback on a v4l2 virtuel device (with bmdcapture tool and ffmpeg)
a long time ago, I noticed that the quality parameter of pix_video on macos was important to get the best quality
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