ofxAddons
Allows to send any kind of image output from OF to any application that can open a v4l2 camera
Forks
Forks pushed to more recently than arturoc/ofxGstV4L2Sink itself, plus any admin-confirmed fork with commits of its own — worth checking if you're hitting issues with the original.
README
Allows to send output from an OF application to any other application that supports v4l2 devices like video conference applications Uses v4l2sink gst element to create a virtual device which can be used as a camera in any application that supports v4l2 To use it just call setup to create the device + update to send the pixels for each frame