/* Usage:
        To gather info about the dvd:
                dvdbackup -i /dev/dvd -I

        Gerneral backup information:
                If your backup directory is /my/dvd/backup/dir/
                specified with the "-o" flag. Then dvdbackup
                will create a DVD-Video structure under
                /my/dvd/backup/dir/TITLE_NAME/VIDEO_TS.

                Since the title is "uniq" you can use the same dir
                for all your DVD backups. If it happens to have a
                generic title dvdbackup will exit with a return value
                of 2. And you will need to specify a title name with
                the -n switch.

                dvdbackup will always mimic the original DVD-Video
                structure. Hence if you e.g. use the -M (mirror) you
                will get an exact duplicate of the original. This
                means that every file will be have the same size as
                the original one. Like wise goes also for the -F
                and the -T switch.

                However the -t and (-t -s/-e) switch is a bit
                different the titles sectors will be written to the
                original file but not at the same offset as the
                original one since they may be gaps in the cell
                structure that we don't fill.


        To backup the whole DVD

                dvdbackup -M -i/dev/dvd -o/my/dvd/backup/dir/

                This action creates a valid DVD-Video structure
                that can be burned to a DVD-/+R(W) with help of
                mkisofs version 1.11a27 or later


        To backup the main feature of the DVD:

                dvdbackup -F -i/dev/dvd -o/my/dvd/backup/dir/

                This action creates a valid DVD-Video structure
                of the feature title set

                dvdbackup defaults to get the 16:9 version of the
                main feature if a 4:3 is also present on the DVD.
                To get the 4:3 version use -a 0.

                dvdbackup makes it best to make a inteligent guess
                what is the main feature of the DVD - in case it fails
                please send a bug report.


        To backup a title set

                dvdbackup -T 2 -i/dev/dvd -o/my/dvd/backup/dir/

                where "-T 2" specifies that you want to backup
                title set 2 i.e. all VTS_02_X.XXX files.

                This action creates a valid DVD-Video structure
                of the specified title set


        To backup a title:

                dvdbackup -t 1 -i/dev/dvd -o/my/dvd/backup/dir

                This action backups all cells that forms the
                specified title. Note that there can be sector
                gaps in between one cell and an other. dvdbackup
                will backup all sectors that belongs to the title
                but will skip sectors that aren't a part of the title.


        To backup a specific chapter or chapters from a title:

                dvdbackup -t 1 -s 20 -e 25 -i/dev/dvd -o/my/dvd/backup/dir

                This action will backup chapter 20 to 25 in title 1, as with
                the backup of a title there can be sector gaps between one chapter
                (cell) and on other.dvdbackup will backup all sectors that belongs
                to the title 1 chapter 20 to 25 but will skip sectors that aren't
                a part of the title 1 chapter 20 to 25.

                To backup a single chapter e.g. chapter 20 do -s 20 -e 20
                To backup from chapter 20 to the end chapter use only -s 20
                To backup to chapter 20 from the first chapter use only -e 20

                You can skip the -t switch and let the program guess the title although
                it's not recomened.

                If you specify a chapter that his higher than the last chapter of the title
                dvdbackup will turncate to the highest chapter of the title.

        Return values:
                0 on success
                1 on usage error
                2 on title name error
                -1 on failur


        Todo - i.e. what's on the agenda.
                Make the main feature guessing algoritm better. Not that it doesn't do
                it's job, but it's implementation it's that great. I would also like
                to preserve more information about the main feature since that would
                let me preform better implementations in other functions that depends
                on the titles_info_t and title_set_info_t strcutures.

                Make it possible to extract cells in a title not just chapters (very
                easy so it will definitly be in the next version).

                Make a split mirror (-S) option that divides a DVD-9 to two valid DVD-5
                video structures. This is not a trivial hack and it's my main goal
                the next month or so. It involves writing ifoedit and vobedit
                libraries in order to be able to manipulate both the IFO structures
                and the VOB files. Out of this will most probably also come tscreate
                and vtscreate which will enable you to make a very simple DVD-Video
                from MPEG-1/2 source.

*/

