JoinMovies is an application that specializes in combining multiple video clips (not parts) of the same format (or similar ones) into an independent movie file. You can join QuickTime-readable movie files (3GP, 3GP2, DV, M4V, MOV, MP4) and make one independent video clip (MOV), which is viewable with a media player. Or restore the original state before a single clip was split into pieces. You can combine AVI movie files (MKV movie files) of the same kind into one AVI video clip (one MKV video clip).
* Please note that JoinMovies may not work with media clips that are protected by DRM.