Unfortunately there's no directly equivalent way to v4l2loopack on Windows.
There are two options,
- You can implement your own DirectShow COM server which serve video data
for client DirectShow source filters as if it's webcam device so that client
DirectShow application can read it from. OBS supports virtual webcam on
Windows using this approach.
- Or, you need to implement Windows driver which serve video data. In this
way, both DirectShow and MediaFoundation (probably Windows kernel streaming
also) applications can also read data from the virtual webcam.
In any case, it's not simple to achieve on Windows.