Ecamm Live's Virtual Camera feature is a great way to send the output of Ecamm Live to other apps on your Mac. The other app will list it as a webcam called Ecamm Live Virtual Camera. Here are some steps to try if it's not showing up.
Ensure that Virtual Cam Is Installed and Turned On
Turn on Virtual Camera in Ecamm Live's Output menu. If it's not installed yet, it will prompt you to install.
Quit and Reopen Video Apps
If you've just installed Virtual Cam for the first time, you'll need to quit the app that you want to use it with and re-open it.
Restart The Mac
If Virtual Cam is still not showing up, and you've just installed it, restart the Mac. Then, open Ecamm Live, ensure Virtual Cam is turned on, and then open your other app.
Ensure That Apps Are Up To Date
Ensure that you have the latest version of the app that you're using with Virtual Cam. Some older version of Zoom and Chrome do not work with Virtual Cam, but the latest version is compatible.
Some Apps Just Don't Work With Virtual Cam (Sorry!)
Certain apps do not load third-party plugins, so they will not be compatible with virtual camera software of any kind. This includes many Apple apps such as Safari and FaceTime. As an alternative to Safari, use Chrome or Firefox.