First if all: Thank you very much for the great support in this forum - this has been helping me a lot with my project!
I'm almost there and created the first Bluray using customized Photoshop menus and an After Effects composition with animated menu buttons. I'd like to have the motion menu playing when the Bluray starts for about 20 sec. (whole clip is about 1:25min.) without any buttons visible and after 20sec. the animated buttons are flying in.
So at first, the button highlights were visible while the buttons weren't there yet, so I set the motion menu loop point in Encore to 20sec. This works fine except one thing: Since the menu would loop at this point, I also do have a short break up of the aufio file. Navigationwise, everything's great but is there any way to have the audio playing without breakup within the motion menu? Is it possible to add the audio to the After Effects composition or does it need to be separated? Or is there any other way to have the aufio playing without breakup?
What Encore actually does is split your motion menu clip into two parts at the loop point. It then causes the intro part to play once, and the rest to repeat. Audio and video breaks occur (depending on the player hardware) at the start of the repeating part, because the player has to preload the menu at that point, and that takes noticeable time. This also means your audio will restart at the loop point, rather than continuing to play on its existing timeline.
This is all because of a flaw (my word) in the Blu-ray spec that prevents a simple delay in the start timing of a menu. There are more complicated Blu-ray mechanisms that I believe will achieve the desired effect, but Encore and most authoring software doesn't support them.
I've seen evidence that some versions of DVDArchitect support menu video loops with a non-zero loop point, but in Encore I think you're out of luck.