VOB is a container format in DVD-Video media which can contain video, audio, subtitle and menu contents multiplexed together into a stream form.
Tips: VOB file can contain H.262/MPEG-2 Part 2 or MPEG-1 Part 2 video, MPEG-1 Audio Layer II or MPEG-2 Audio Layer II audio, but usage of these compression formats in a VOB file has some restrictions in comparison to the MPEG program stream.
Did you try to import VOB video to Motorola Droid X for playing?
To play the VOB files, you need to have a DVD player that supports VOB format. However, if you have the Windows Media Player (version 12 or higher) or VLC Media Player, it is good enough to play the file. However, Motorola Droid X can not accept this format.
Fortunately, VOB to Motorola Droid X converter convert VOB video to MP4 for importing to Motorola Droid X.