You remember Greek Subtitles Encoder Project ?
I just updated it for Linux Mint. Mint v15+ users or Nemo 1.8.2+ users will be able to right click subtitles and encode them instantly.
Most Greek subtitle files are encoded as "windows-1253".
In Ubuntu the default decoding is UTF8. So when user tries to play a video file with greek subtitles that are not in UTF8 format , the player displays wrong characters.