Closed captioning has been around for many years. It is included in most programming and consists of a subtitle track that contains the text of the dialogue (and who is speaking it) and indications of other non-speech sounds that are happening while a show is playing.
Audio descriptions are a newer technology that can supplement closed captioning. Audio descriptions provide narration tracks within the audio stream, describing what is going on visually on the screen.
Below is a table outlining a few key differences between these technologies:
|Who They Serve||People who are deaf/hard of hearing||People who are blind/low vision|
|How They Are Incorporated||Into the visual stream of the video||Into the audio stream|
|What They Convey||Spoken dialogue, who is talking, and non-speech sounds||What is happening on-screen|
|How They Are Created||Captioner adds subtitle file, including sounds heard in the audio track||Add an audio track on top of the original soundtrack to describe what’s seen visually|