To make a DVDRip, you need to copy the main movie of the DVD to your hard drive, and then re-encode it to reduce size. DVDRips are usually AVI files, with MPEG 4 ASP video and mp3 audio (such files are usually called "Divx" files). DVDRips are always standard definition, and some times even lower than that.
Since DVDRips use a video format that's superior to the one the source uses (MPEG 4 ASP vs MPEG 2 of the DVD), it's possible to dramatically reduce the size of the rip compared to the original.
If you are willing to compromise quality and detail, you can reduce the size even further, often reaching into such small sizes as 700MB (1/10 of the original), but quality will be rather low.
A good quality DVDrip of your usual hollywood movie is 1~1,2GB in size, while 700MB~800MB is a rip of rather poor quality.
DVDRips are arguably the no1 method of piracy and the easiest way to download a movie from the internet. Also, since DVDrips are Divx files, they can play on all Divx capable DVD players, making them an even bigger pain in the back for greedy hollywood studios.
"The most widly used tool to create DVDrips is AutoGordianKnot, which is based on the Xvid tool"