x264 is an open-source encoder for the H.264 codec used for High-Definition movies on HD-DVDs and Blu-Ray Discs. It has a high compression which is way superior to xvid. That means you get more quality at equal bitrates. A 700MB x264 rip will be sharper and more detailed than a 700MB xvid rip from the same source. x264 is the future in DVDrips!