User control over of the presentation of subtitle (text representation of speech, for localisation) and captions (text representation of important audio, for accessibility) is a legal requirement for some videos played at system level, specifically video that falls under CVVA – video that has previously been captioned for television broadcast.
The obvious application for system level preferences is for system level video, such as Blu-ray and VOD. However, it would be ideal for the preferences to also be exposed for developers to pull in as default values for their own in-game subtitles and captions (see Expose as many system level accessibility preferences as possible to developers).
There is a standardised set of options defined by VPAAC and backed by the FCC, specced out in a standard called CEA-708 which has been adopted across technologies from smartphones to TV on demand services to games consoles. It requires options for the following:
- Text & letterboxing color override, to white, black, red, green, blue, yellow, magenta, cyan.
- Ability to override font choice with options including monospaced serif, proportional serif, monospaced sans serif, proportional sans serif, casual, cursive, & small caps
- Opacity level of both text and letterboxing, letterboxing from 0% to 100%
- Text size, from 50% to 200% of default
- Text edges, including none, raised edges, depressed edges, uniform edges, and drop shadowed edges
It also requires settings to persist between sessions, and a preview function to be available.
Xbox One caption presentation options, with preview panel