Is a two screen video-conferencing app possible?

[TIMAI2]

See here:

Video Call on AI2?

Worth a look…?

or here

Is it possible to make a video's call in mit app inventor

You cannot make a video call app using App Inventor Blocks alone. Here is a possible way using a service (that use of the service has charges) Video Call on AI2? The agora service indicates Pay-as-you-go​ …Pay only what you use, with zero upfront cost.

for some ideas

May be easier to use the activityStarter to call via whatsapp/duo/skype etc ?