I had occasion to use this program because I procured -- ahem! -- a foreign language film for the Literature class I teach. Unfortunately there were no subtitles. I managed to locate a decent subtitle file, but it was timeshifted several seconds early. I did a quick search for tools that could help me synch the subtitles with the video properly and voila!
gnome-subtitles
fit that bill.
Guess what film we're watching?