v4l2loopback-linux-module 0.12.5 Linux kernel module to create virtual V4L2 video devices

This Linux module creates virtual video devices. V4L2 applications will treat these as ordinary video devices but read video data generated by another application, instead of a hardware device such as a capture card.

This lets you apply nifty effects to your Jitsi video, for example, but also allows some more serious things like adding streaming capabilities to an application by hooking GStreamer into the loopback device.