Do you want to join VOB files all up to make a whole file or merge VOB files into one? There are two different situations existing in our own needs. One is that VOB files are stored in VIDEO_TS Folder accompanied with IFO and BUP files. It's actually a whole DVD folder file containing all data for a DVD movie. You can merge vob files by ripping VIDEO_TS folder to a digital video with some DVD ripping tool. The other is that VOB files are separate from VIDEO_TS folder. Some VOB merger or VOB joiner can help you combine VOB files together. Also, some free video converters like Freemake, Format Factory, AVC all own the ability to merge VOB files and convert to MP4. The operation process of both situations are not complicated...