Audio cuts out most of the way through an iDVD image

Question

We created a Quicktime file using Final Cut Express HD 3.5, and imported the Quicktime fill into iDVD 6 (all patches have been applied to iDVD and to Quicktime, and Quicktime has been upgraded to Pro version). The iDVD preview shows that all audio is present all the way through the end of the video(about 1 hour and 5 minutes), which means that the Quicktime file has all the audio present.
However, after creating a DVD disk image with iDVD 6, the audio cuts out completely about 55 minutes into the video. The spot where the audio cuts out is not near any chapter marker nor near any transition of any kind in the Final Cut editor session.
By the way, I am creating the image on an external Firewire drive with 112 Gbyte free, although we also tried the internal hard drive which has about 20Gbyte free.
How can I figure out how to get all the audio onto the image created by iDVD?

Answer 1

I believe I've found the cause of the problem! Within Final Cut Express, I found a system setting for output buffer size, set by default to 2Gbyte. I also found that the default 'Convert to Quicktime' setting is for Internet Fast Start. I increased the buffer size from 2Gbyte to 3Gbyte and unchecked Internet Fast Start, and I have no more audio drop out!
I think that iDVD has a bug when multiple file segments are linked together in the Quicktime file (because of the smaller FCE output buffer size). Note that the iDVD preview did not experience the problem, so that part of the iDVD app seems to handle multiple file segments correctly, whereas the part that processes the file segments while creating the DVD image seems to have the bug. Increasing the buffer size masked the iDVD bug.
So if anybody from Apple is listening, please fix your iDVD bug please!
Concerning the ZR85, I do re-use tapes quite a lot and have never experienced problems. I do clean the ZR85 heads periodically. However, I shall consider using new tapes more often.