alass is a command line tool to synchronize subtitles to movies.

It can automatically correct
- constant offsets
- splits due to advertisement breaks, directors cut, ...
- different framerates

The alignment process is not only fast and
accurate, but also language-agnostic. This means
you can align subtitles to movies in different
languages.

'alass' stands for  "Automatic Language-Agnostic Subtitle Synchronization".