That depends. If you want it to be a true "video" DVD, as in the kind that you play on your TV, then you *have* to compress it to fit the MPEG-2 standard anyway. But in all actuallity, you won't have to worry about compressing it, as iDVD will do that for you. Assuming that the DV file is less than 90 min. in length, that is.
If you're just backing up the file, on the other hand, you could compress it to any format you want (DivX, XviD, MPEG-4, AVI, animated GIF.. er... no.). Or, you could leave it uncompressed and span it across many DVDs.
Hope that helps.
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