Hi, it seems to be working for me, the basics are to 1) Set up your MP4 videos in the plugin parameters -> Videos -> MP4, 2) Play a movie with the same name via the Play Movie event command.
Note that the editor only displays .webm movie files. Plugins cannot modify the editor, so to get around this RPG Maker limitation you will need to create a blank .webm file of the same name to be able to select the file in the editor, however as long as you have the plugin parameters set up to load an mp4 for that video file it will show the mp4 video.