Here are ways to view and edit the background movie:
To view the background movie, drag the diamond-shaped motion playhead along the scrubber bar (shown below), stopping wherever you like.
(If you don’t see the motion playhead in iDVD, choose View > Show Motion Playhead.)
If you don’t want to use the intro and outro in your DVD menu, deselect the checkboxes at the left and right end of the scrubber bar.
The scrubber bar shows the intro and outro as shaded areas at the beginning and end.
You can also control the intro and outro from the Menu Info window. With your pointer over the menu (and with no buttons or text objects selected), press Command-I to open that window. Select or deselect the Intro and Outro checkboxes in the Background section of the window.
To turn off menu motion completely, open the Menu Info window and move the Loop Duration slider all the way to the left, so the duration is zero seconds.
If you simply want to shorten the loop duration, move the slider to the left until it shows the number of seconds you want the loop to last. The entire loop will play in the timeframe you set.