During a Studio session, Riverside displays the video frames of all participants in equal sizes. To make one participant's video fill the screen instead, follow the steps below.
Step by step:
Using your computer, join a Riverside Studio.
Right click (or ctrl-click) on a participant's video frame.
On the context menu, click Show All Controls.
Near the bottom of the video frame, click the Fullscreen button.
If you view your own video fullscreen, it displays the video without mirroring.
Press the esc key to exit fullscreen.