VobMerge is described as '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'. There are three alternatives to VobMerge for Windows. The best alternative is DVDVob2Mpg, which is free. Other great apps like VobMerge are Join Vob Files Tool (Free, Open Source) and VOB2MPG (Freemium).
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:
VOB2MPG 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.