Do you mean a DVD-a disc, high def audio or multi-channel audio, or just a high capacity disc with lots of aiff files?
Video DVDs use lossy compression (e.g. AC3) for 5.1 audio. DVD-Audio can include an audio stream with lossy compression as well, but the primary advantage of DVD-A is that the audio stream can be compressed with a lossless compression algorithm for better quality. It's possible to have 24 bit audio in stereo at 192kHz, or in 5.1 at 96kHz on a DVD-A disk.
Unfortunately, the software needed to produce proper DVD-A's is extremely expensive and doesn't usually run on Mac OS X. Three examples are discWelder, Sonic DVD-Audio creator, and Dolby Media Producer (runs on Mac OS X).
That software can burn limited DVD-A's, but since it can't apply MLP compression to the audio, it's not possible to use 5.1 with higher sample rates. Also, without compression, playing time will not be as long.Not exactly correct. There is a free DVD-A authoring program (by xACT creator) called DVD-Audiofile. You should be able to download it here:
http://satellite.epix.net/~scb/index.php?path=dvd-audiofile/
This will create a disc image of a DVD-A that you can then burn with Toast, Disc Utility, etc. It was designed for the live audio recording folks who trade in FLAC files, and seems to work best if your audio is already in FLAC.
That software can burn limited DVD-A's, but since it can't apply MLP compression to the audio, it's not possible to use 5.1 with higher sample rates. Also, without compression, playing time will not be as long.