Captions vs subtitles
In a short break from the editor series, and in the spirit of If you write it down you'll remember it, I'm going to risk a mauling by defining captions and sub-titles for video.
Not that they haven't been defined already, but I am a British person guilty of having:
the worst possible terminology for captioning and subtitling.
I thought that as one of the guilty, it would worthwhile setting down. Here goes:
Captions
Aimed at the deaf and hard of hearing, and assume you cannot hear the sound.
They include indications of who is speaking, and relevant sound effects (like the phone ringing).
They are usually "closed" (which seems to mean you can turn them on or off).
Think the teletext page 888 on TV. (For the british audience.)
Sub-titles
Aimed at those who can hear, but not necessarily understand the language.
Do not bother showing sound effects or usually indicating who is speaking.
They are usually on (not optional).
Think foreign films with sub-titles.
There is much more to it, and it's worth reading more, although beyond these absolute basics, the differences seem to be "tendencies" or "usually", presumably due to the poor implementations.
I generally deal with the web rather than television or DVDs, so my worry has always been about adding captions, as that is the obvious accessibility issue.