VOB2MPG is described as 'have allowed users to join up and process vobs found in dvds - resulting in mpeg files suitable for playing or authoring. VOB2MPG v3.0 (PRO) also does this but, in addition, allows users to choose, at a finer level, the DVD content to be extracted' and is an app in the CD/DVD Tools category. There are three alternatives to VOB2MPG for Windows. The best alternative is VobMerge, which is free. Other great apps like VOB2MPG are DVDVob2Mpg (Free) and Join Vob Files Tool (Free, Open Source).
VOBMerge is a tool for merging (joining) several .vob files into one file. This is useful for seamless playback or editing of DVD video on your harddrive. VOBMerge 2.52 Remixed gives you a few new functions such as batch ability. See readme.txt for more information.
Join VOB Files Tool is a free, open-source software to join (multiplex, merge, combine) VOB files from DVD structure to use joined files in next encoding, conversion, demultiplexing, audio and video streams extracting, etc. How Join VOB Files Tool works: