You need to determine the type of DVD you have because dual layer can refer to DVD-9, DVD-10 and DVD-18. Most burning guides refer to the "DVD-number" rather than "dual layer".
DVD-5 is the bog standard single-sided single-layered disk. You tend to get these with budget DVD releases where there are no special features. DVD-5 has a capacity of 4.7Gb which means you can do a disk to disk copy.
DVD-9 is a single-sided dual layer disk. This is pretty much two DVD-5's stuck together (not technically correct but you get the idea). These are favoured for the big budget films where cool menus and special features are used. DVD-9 has a capacity of 8.5Gb which means you either have to shrink or copy to two disks.
DVD-10 is double-sided single layer disk. This is a disk that you turn over onto the B side to watch other bits and pieces. This is cheaper to make than DVD-9 and is favoured by box sets of series because you can squeeze more info due to the 9.4Gb of capacity.... an extra 1Gb over the DVD-9 format. You can shrink or copy onto two disks.
DVD-18 is double-sided and double layered. This disk is quite expensive to make but offers 17.1Gb of capacity. Because of the cost many studios release on two DVD-9's instead (DVD-9 is the most common format atm). Although they are not that common, more studios are starting to use these for budget releases where they stick four or five films onto the single disk. I expect that by the end of this year you will be seeing a lot more of them.
You may even come across DVD-14 which is a double-sided disc with a single layer on one side and a dual layer on the flip side. It was cheaper to produce than the DVD-18 and had a capacity of 12.33 Gb. Although this died away in the late 90's its had a recent spurt of life with people releasing audio tracks on. I doubt you'll see movies released on this format tho.
Its a format hell
and the point of this post?? well, I guess you should be talking in terms of DVD numbers because thats what the best tutorials use
Regards,
f.
