It is possible to break down the two disc images (.cdr files) into their component parts and reassemble them onto one DVD. Typically, MPEG Streamclip is recommended as part of this workflow, but I don't see any reference to .cdr formats in their manual.
Anything that plays on your Mac can be captured by SnapZ Pro (video and audio) and saved to a Quicktime file and brought into iDVD, so that's an option.
Another option appears to be Roxio Toast. Here's what it says about merging disc images (you'd be merging two similar images rather than one of each):
Merging Disc Images
Disc Image Merge is useful for software developers who need to produce
cross-platform Mac & PC discs with unique content for each platform, and
who are producing unique images on each platform. You can create your
Mac disc image using Toast, and you can create your PC disc image with
popular PC software, such as Roxio’s Easy Media Creator®.
1 At the left side of the Toast window, click Copy and choose Image File.
2 Select the Mac and PC disc images to be merged into a new disc:
■
To select the Mac disc image, click on the Select Mac Image
button
■
To select the PC disc image, click on the Select ISO Image button.
3 Click the red Record button, choose a recorder from the list, and
configure recording options, such as Number of Copies.
4 Click Record to continue.
Seems like an easy proposition (combine two into one), but it might take a little effort.
John
