Defining Captioning and Audio Descriptions
Captions
Many sources within W3C have developed their own definition of captions. These include, but are not limited to:- The Web Accessibility Initiative defining captions as a text version of the speech and non-speech audio information needed to understand the content. They are displayed within the media player and are synchronized with the audio..
- Media Accessibility User Requirements defining captions as being for people who are deaf or hard-of-hearing, captioning is a prime alternative representation of audio.
- Web Content Accessibility Guidelines (2.1) defines captions as synchronized visual and/or text alternative for both speech and non-speech audio information needed to understand the media content.
Audio Descriptions
A related concept to captions is audio descriptions. These, again, have a number of definitions and include, but are not limited to:- The Web Accessibility Initiative describing audio descriptions as providing content to people who are blind and others who cannot see the video adequately.
- Web Content Accessibility Guidelines (2.1) define audio descriptions as narration added to the soundtrack to describe important visual details that cannot be understood from the main soundtrack alone.
- Audio Description is a related concept to captioning because both require an artistic ability to summarize visual information that is happening simultaneously.
A Mixed Reality Definition
Captioning in Mixed Reality relies on two related concepts:
- The ability to understand the purpose of a sound within an environment
- The ability to locate that sound within 3D space
The combination of these concepts soften the boundaries between captioning and audio description as both elements are required within XR captioning. Understanding sound purpose is most likely to be achieved through captioning. Locating sound within space is most likely to be achieved through audio description.
We propose that captioning and audio description in XR should be considered as a single element but with two separate and distinct component parts. We believe that this change will promote activity to counter the accessibility constraints that appear for all users when using XR and will assist in developing more accessible experiences.