Place a small webcam-video window on top of desktop sharing / picture-in-picture

Hi. My company is really interested in a web meeting platform that can place an image of the person speaking on the screen at the same time that someone is sharing screen. In sort of a picture-in-picture mode. Something like this:

example webcam in screenshare

Where the windows background comes from the screen share source and the little picture comes from a meeting attendee’s webcam feed.

Bonus: allow the meeting host to spotlight which user appears in this mini video screen
Bonus: allow the person sharing their screen to move the video around somehow in case it covers up something important.

Any chance of building something like?

So this a good start. But what if someone else (other than the screen-sharer) is speaking? We would like the option to place that speaker in the small window at will.

Basically so that more than one person could take turns presenting a single power-point presentation.