Reviewing videos frame-by-frame (aka frame stepping) in a CORE LIVE session is dependent on the tools you're using to stream your video.

Neither OBS nor Flowcaster offer video controls to view a video by frame, however, you can stream your editing applications through them to ensure frame stepping accuracy.

To stream your editing applications where you can frame step, go to How to Stream an Editing Application to 5th Kind LIVE and Live Rooms.