extract a part of a vob file

how can i save a portion of a .vob file as an .avi file.which software do i need.

[drgrudge]

Use DVD Decrypter.

DVD Decrypter is a free tool that allows you to decrypt and copy DVDs to your PC's hard disk. From there you can watch them with the likes of WinDVD and PowerDVD, you can write them back to DVD-R / DVD-RW / DVD+R / DVD+RW / DVD+R DL / DVD-RAM media or you can convert them to VCD / SVCD / DivX for burning onto CD-R / CD-RW.

DVD Decrypter can write most types of CD / DVD images via its 'ISO Write' mode, and it supports all the latest writers (including booktype / bitsetting on many of the major ones - i.e. BenQ, LiteOn, NEC, Plextor, Sony). You can even use DVD Decrypter to erase / format your rewritable media!

http://www.dvddecrypter.com/index.php?act=download

After that you will autoGK to convert that vob files to .avi.
Use autoGK, only if you have a fast connection.