SlackBuildsOrg/multimedia/subtitleripper

DVD Subtitle Ripper for Linux

If you want to convert DVD subtitles into text format (e.g. subrip format) or 
VobSub format this program could be useful for you. However, it is only one 
tiny tool that you need in the process of producing srt files. This software 
depends heavily on transcode for its input and is therefore part of the 
transcode package (see transcode's contrib directory). So, if you want to 
convert some subtitles, grap a copy of the lates transcode distribution.

For srt file production the output of this program should be processed 
by some OCR software. 

For VobSub output no other tools are required.