After sharing out my movie to a friend who is hearing impaired, I decided to look into how I would go about making sure that my movies would be accessible to her.
Closed captioning for movies is supported by embedding the subtitles in the movie files themselves, or through the use of external files.
My first thought was to attempt to embed the files as provided by the DVDs or Blu-Ray discs. As it turns out, this approach is a bit fraught with peril as I’ve found that getting Handbrake to do the right thing was a bit hit or miss, but you can find some good instructions online. I’ve occasionally ended up with permanently turned on closed captioning for specific movies, or just ending up with foreign subtitles rather than English closed captioning. Not to mention that this approach would require re-ripping all existing media files which were not ripped with them enabled.
The easier approach is through the use of an external file. These closed captioning files can be found online on a number of websites like OpenSubtitles or Subscene. Even better, the operation can be automated by various Plex plugins. I use Sub-Zero which is itself a fork of Subliminal. Installation of the plugin itself is probably best left for another post.
One item to note regarding using these plugins for downloading subtitles is that it will require the Plex server to have write access to your content directories. Typically Plex only requires read-only access, so you may not already have this set up. This can be done by simply adding the plex user to the group which owns the content directory and ensuring that group write permissions are set.