I am looking for a way to allow max 20 children in a classroom to stream their live phone video feed to a projector using NDI (HX) in vMix.
Those NDI sources will appear in the NDI input overview, and I can select the desired NDI source to add it as an input for display on the projector.
I assume that with only NDI previews, there won't be any bandwidth issues.

I have been searching for a free NDI camera app, but the only one I could find is NewTek NDI HX Camera, and it's not free.
Because it concerns different children, the idea is that they can easily and quickly install and remove the necessary app without having to create an account.

I have been thinking about a way to cast to a TV, but I wouldn't know how to pre-select a specific phone to display.