Dvd Structure

The DVD hierarchy is like this:

VIDEO_TS.IFO VIDEO_TS.VOB VIDEO_TS.BUP: This is the information for the main menu, and the VMG (video manager) information file
The main menu is in the vob file
The bup file is a backup (copy) of the ifo file
The IFO is very important for determining how to play the movie.
- it contains pointers to all the data locations in the VOB or set of VOBs
- the data in the VOB is resilient to scratches and stuff, so it's not so bad if that gets scratched up
- but if you lose an IFO... you're toast.
On the dvd is a collection of titles
Each title has a menu, and the vob title set.
Each title set has a main menu for the set and the ifo for the set
VTS_01_0.IFO VTS_01_0.VOB VTS_01_0.BUP
Then, you get the data: VTS_01_[1-9].VOB
- each of those files is only a gig, but that's a filesystem limit
- in actuality, all the data is contiguous on the disc
and you load it from the first sector of the first vob in the set and keep reading
- even further, everything from the first ifo in the set is contiguous on the disc.
- (you need to know that, since alot of info is given in sectors)
- in the vob set, it's split up in different ways
but probably the best way to think of it is as a collection of VOBUs
- and then you can organize VOBUs into cells, cells into programs, ...
- each VOBU is a collection of packs
- a pack is 2048 bytes, the size of a sector on a DVD

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