From Software on the Side:
The burn process in iDVD3 is shortened considerably if MPEG2 encoding is completed in the background before starting the burn. The problem is: What happens if you have a bunch of projects you want to encode before starting to burn any of them? The manual method requires you to keep track of the encoding status and then, when it's done, to save the current project and open the next. It requires you to oversee the whole process, which means you cannot encode them overnight when the computer is otherwise unoccupied, unless you're willing to get up every hour or so to switch projects. ayeDVD Batcher allows you to "set it and forget it". Just define the projects you want to encode and start the encoding process. The projects will be processed sequentially, with each project being opened and staying open for as long as it takes to encode it.