MoviX is a mini Linux distro on CD aimed at playing multimedia: when you boot your PC with the MoviX CD the distro should be able to start a console menu interface to MPlayer, the best multimedia player in the Unix world.
At that point you can safely remove the MoviX CD and play all multimedia files you want: DVD [no zone constraint], VCD, DivX, QuickTime, avi, mpg, mp3, ogg etc.
The idea of MoviX came up to solve two different problems arising from eMoviX.
First of all with eMoviX you cannot watch DVDs, mainly because you have no space to copy vob files in a 700MB eMoviX CD.
Furthermore, those of you who have already a big archive of multimedia CDs would probably not happy at the idea of "eMoviX-ing" them all.
MoviX solves both problems: it is not made to be embedded with the movie in a CD but just to be loaded in a PC to transform it in a true MultiMedia Box, so after that you can extract from your CD/DVD-ROM the MoviX CD and insert & play every DVD/VCD/CD you have around.
So remember: MoviX is not an "improved" version of eMoviX nor a replacement for it! It has a totally different philosophy behind, the mplayer binary is compiled with different options and it is used for different purposes.
The name is similar because anyway they are both related to Unix and movies :-)