This is a variant of the Echo Test demo: everything is exactly the same in term of available controls, features, and the like, with the substantial difference that you can select which of the available devices (microphones, webcams) you want to use for the media setup.
The demo will start by automatically selecting some default devices,
pretty much as the regular Echo Test demo already does. Once done,
you'll be able to individually change the capture audio and/or video
device: this will result in the Echo Test channel being reset and
recreated, in order to use the device(s) you selected instead. Just
as with the regular Echo Test demo, the ?simulcast=true
query string will allow you to test simulcasting as well.
The demo exploits a functionality made available in the
janus.js library, meaning you should be able to
easily adapt all the other demos to follow the same approach as
well, and that you'll be able to do the same in your Janus-based
web application too.
Press the Start button above to launch the demo.