Ever downloaded badly synced SRT files, because someone converted framebased subtitle files to SRT without considering the right framerate? I have, and it annoys me pretty much. UI tools usually take more time in fixing this (because they generally do not offer the options of converting a framerate in a time-based format such as SRT). With this little command line tool you'll fix within seconds.

Convert 25-based to 24-based framerate

$ python2.7 srtfix.py -i src.srt -o out.srt -f 25/24

Convert 23.976 to 25 based and shift the SRT 3 minutes right

$ python2.7 srtfix.py -i src.srt -o out.srt -f 23.976/25 -s 3m

Use pipes in stead of arguments

$ python2.7 srtfix.py -f 25/24 < src.srt > out.srt