DVD Copy Protection
A lot of DVDs use copy protection to stop pirate copies being made. Whilst this is all well and good for crime prevention, it can cause all sorts of problems if you wish to play the totally legal copy of a DVD you've purchased on your PC or MP4 player. This copy protection will cause problems for anything that's not a bone fide DVD player and it not a particular issue with Linux PCs.
DVDs (-at least the ones I own) tend to use a system known as CSS(Content Scrambling System) to stop illegal copying and distribution.
Now, I must point out that we are in no way condoning or encouraging people to pirate or otherwise make illegal DVDs: this should only be used to copy your legal DVDs to another device for your convenient viewing. It is illegal to make unauthorised copies for sale or distribution and entertainment companies come down hard on anyone found doing that sort of thing.
In our opinion, there are only three cases for converting a DVD to digital format:
Downloading your own DVDs to a portable MP4 player, to view whilst away from home
To setup a central PC as a media player in your house, you will need to load your DVD library onto the hard disc(s) in order to populate the library
If your main DVD player is broken or otherwise need to view the DVD via your PC's DVD drive
Provided your need fits into the above, you should be OK to install the CSS library.
In Ubuntu, you can install the copy protection libraries by opening up a command line window and type the following:
$ sudo /usr/share/doc/libDVDread4/install-css.sh
In Fedora, you can likewise install the copy protection from the command line, using the Livna library:
$ sudo rpm -Uvh http://rpm.livna.org/fedora/10/i386/livna-release-9-2.noarch.rpm
$ sudo yum install libdvdcss