Selectively disable receiving video track for participant that not in viewport

For a big conference (e.g., 50 or more), a maximum of 25 thumbnails will be displayed at a time, so it would be good if we can disable video track for participants that are not in the viewport. This would reduce both CPU and bandwidth usage.

Detecting video tracks that are not in viewport is easy, however, I do not have idea how to pause/resume the video stream.

Any idea how to implement that function? or where to look at? Thank you.

@damencho Do you have any suggestions on where to start?