Sub stands for Divx subtitle file. You can open sub files Subtitle Workshop or Videolan software.
It is derived from Subtitle word. If you need any subtitles for downloaded movies you may need sub extension files. You should give the same name to this file with the movie.
There should be a batman.sub file with batman.avi
You may use Videolan or Bsplayer softwares to view sub files. These softwares may open subtitle file automatically and show on the movie. You will not need any extra software with Videolan software.
You may need to edit or combine the subtitles, in this case, you can use Subtitle Workshop softwares.
What to use sub
Subtitle Workshop, Videolan
which page related to sub file
sub Related Searches
You can check related links about sub fileextension.