Jubler enables you to create and translate subtitles for video files. Using Jubler you can export the subtitles as a text file which can then be used by a variety of applications including VLC to play back the subtitles with the video. These text files can also be used by DVD authoring programs to embed the subtitle file in multilingual DVDs.
For playback Jubler uses MPlayer (video player software) to preview files and aspell (spell checking software) to spell check the subtitles. You need these two programs installed for Jubler to operate and hence it's trickier to install than similar programs. The good news is that once it is installed it works beautifully and it works the same on OSX, Linux, and Windows.
For further instructions on installing Jubler, please see the specific Jubler manual at FLOSSManuals - http://en.flossmanuals.net/