I'm running iDVD 7.1.2, using the Superdrive that's the USB accessory for the iMac and I've tried Verbatim and Memorex.
I don't think it even gets to the part where it goes to the media, so I'm not sure what the issue would be. The dual layer I'm trying to use is the Verbatim.
I don't know how to add chapters to iDVD, I just got it on here a few days ago, so I haven't had a ton of time to play around. But I just used the "magic dvd" function, then edited to add clips for the menu drop zone and the titles.
I've read that the 30fps might be an issue, but I couldn't find anywhere in iMovie where I can edit the output settings.
DVDs are by standards just 720x480 in resolution… about a quarter of your actual footage.
And playback a DVD 'full screen' on an iMac zooms-in again, blowing up the few pixels, about by factor 6x.
keep this in mind, when judging 'quality'.-
To get max possible quality, stay under 60min of content on SL dvd-r, 120min on DL dvd-r
Putting <60min on DL has no effect, just draining your wallet …
In iMovie, choose Export using Quicktime, in the many options, select AppleIntermediateCodec, which will export the internal timeline of your project without any un-neccessary transcoding. File is huge, don't worry, it's all about length. not size.
Drag resulting mov into iDVD. Works perfectly here…
Worked, to be precise. Haven't done a disk for years now