Difference is that in DirectRT they will (if all goes well) be perfectly in synch and start without a lag. MediaLab is limited to a single main video although you can also add a background video. To get to 4 (or more) you would need to use HTML ... OR a PowerPoint show might also let you do it. Try dropping your four videos on a PowerPoint slide and see if that works for you. If you want it on the same screen as your selection buttons (as opposed to that following the videos)... then you could again, use HTML as a background with the video embedded. You also try saving that PowerPoint show as an HTML file and see if that will work for you as a background. Never tried that but it might work.