Thoggen is a tool for backing up DVDs to the ogg container with the theora video codec and vorbis audio codec. Theora is the darling video codec in Linux because it is unencumbered by patents. There are other free formats, such as Xvid - a format compatible with Divx, but it is based on MPEG-3, which is patented by the group the controls the MPEG standard. Technically all encoders need to pay them a fee to encode to MPEG formats. This can get expensive - M$ is curently being sued by one of the patent holders of MPEG Layer 3 Audio (AKA MP3) for a very large amount of money. I *think* it’s in the billion range, but I could be off by an order of magnitude. So, theora, which was licensed to the open source community, is the safest bet.