Subtitles come in handy to people with hearing problems or who aren't familiar with the language that's being used in the movie they're watching. Unfortunately, Mac OS X doesn't provide you with a default tool for handling this type of files. For this reason, applications like Jubler were created.
You can use this program to create, edit, and convert subtitle files on your Mac. The utility works with multiple subtitle formats and provides you with various editing and view options.
Another important advantage is that the app lets you check if your subtitle is in sync with your movie. It also gives you access to an integrated spell checker and chars counting tool.
My only problem with this program is the fact that it communicates only with one video player, a third-party application which needs to be installed on your Mac to check the sync between your subtitle and your movie. Still, the player in question is open source and is feature-rich so it comes as a great alternative to using Mac's QuickTime tool.
In conclusion, Jubler proves to be a reliable solution for editing and converting subtitle files on your Mac. It's feature-rich, brings you easy-to-configure output settings, and is open source.