Mainstage's preferred audio file format is Apple's Core Audio File. One of the nice things about that format is that it can contain song/section markers which can be hooked up to Mainstage controls to allow for jumping to specific sections within a recording. I can use Logic to put my own section markers in, but I'm just repeating what BIAB already knows: what's the intro? Where are the chorus's. Where does the tag ending start, etc. Once I have the tune the way I like it in BIAB and want to export the audio for use in Mainstage, there's no reason that BIAB can't generate that info for me.

Thanks for the great product and keep up the good work :-)

- Mike.