Unlocking iMovie '09 & '11
Well, it's been awhile since I posted any more information about using GarageBand for DVD chapter markers. Since that time I have come across two very common problems that people have encountered in the process:
1. Large movies sent from GarageBand to iDVD lose their audio track.
2. DVD quality can be poor.
Here are two very useful pieces of information for those have been experiencing these problems.
1. Apparently, the audio dropping during the move from GarageBand to iDVD is a known issue. Sid shared in the comments on the original post that deselecting "Auto Normalize" in the Advanced pane of the Preferences.
I haven't experienced the problem, so I can't confirm that it works, but this is certainly worth a try.
2. There has been a lot of discussion about the best way to squeeze the highest quality DVDs from your audio. The problem is that iMovie requires you to render your movie before you can send it to iDVD, where it just gets rendered again into MPEG 2 format for DVD players.
I have it on good authority from a very knowledgeable expert at Apple that the best quality will come by exporting from iMovie using the Apple Intermediate Codec. You can access this as an export option by choosing "Export Using QuickTime" in the Share menu.
Once there, select "Movie to QuickTime Movie" in the Export dropdown menu. Then click "Options." You will see this window.
Click the "Settings" button to access and choose the Apple Intermediate Codec.
You will also want to export the right size of file. You can do this by clicking "Size" in the Options window. For people in the US, NTSC at 720 x 480 is a good size for widescreen content. If is is 4:3 content, choose NTSC 640 x 480.
Once you are done, export it to your Movies folder in your home folder. You can then add chapter markers in GarageBand, which you read about here:
How to add chapter markers
Or you can send the file straight to iDVD. Just open an iDVD project and drop in your movie file.