Try adding a motion menu to your project. Then edit the menu. Change the background ... Select the folder, not the camera, so you can search for MPG files. Select your video. Menu video loops. Then remove all but a single button. Set that button to start chapter 1. Check the setting for automatically return to menu after each chapter. Add your video to the timeline. Set chapter 1 marker to the space between the menu and your video. Save your project a create your dvd. The menu should loop your video continuously. If somebody clicks the Play button, it will play your movie, then loop back to your menu, which plays your movie as a motion background.