Export as Quicktime Movie. If iDVD is on the same machine, then UNCHECK “Make Self Contained”. This will make a Quicktime reference movie of your timeline…there will be no additional compression or degradation from what you see in FCP. The file will be fairly small…well under a GB for a 34 minute film…
Drag that file into iDVD. iDVD handles the MPEG2 compression. Thats it. Dont do any Quicktime conversions to other codecs, such as Sorenson…this will completely destroy your image quality.
Most DVD players can handle DVD+R and DVD-R, but there are no guarantees. Different models have different capability. From what I have read, DVD-R is slightly more likely to be compatible.