Having your DVD start with a short Intro Movie is a very professional look. The transition from the Intro movie to the Main Menu; unfortunately can be a little clunky. To avoid the transition all together, we can produce a movie that becomes our main menu background, and then loop the menu display to the point of the background movie that is the Main Menu.
The issue here is that now every time that a Menu or Track are routed
back to the Main Menu, the Intro Movie will play again. A great
solution here is to duplicate the Intro/Main Menu and route everything
to that menu. The duplicate will have a start point that is the same as
the loop point of the Intro/Main Menu. The viewer will only see the
Intro/Main Menu once, and depending on the where the best place to loop
the audio is, you may have the Intro/Main Menu jump to the duplicate
after it plays through. The reason is that an overlay will not appear
until the loop point, and you may have different points where you want
the overlay to come on, and the loop point. In addition to routing the Menus and Tracks to the duplicate, be sure to route the Menu and Title buttons of the overall Disc.