Media Accessibility Function


The Media Accessibility caption functions provides access to user captioning preferences. Both iOS 7 and OS X 10.9 allow users to create custom styles for caption appearance. To understand the context of the Media Accessibility framework, you need to understand the available user settings. These options are provided in the Accessibility section of System Preferences application as shown in Figure 1. The settings affect attributes such as caption color, font, and language. Some of the options are shown in Figure 2. By choosing custom styles for media text, users are requesting improved legibility.

Figure 1

Accessibility preferences pane in macOS

Figure 2

Caption appearance preferences pane in macOS

The Media Accessibility functions are provided for you to tailor the user experience of your media content. You must be able to influence the caption rendering process at time of delivery for the following functions to be useful. Retrieving the user's preferences and dynamically rendering the captions for maximum readability provides the best user experience.


Accessing Language Preferences


enum MACaptionAppearanceDomain

A value used to specify which domain a preference setting is retrieved from.

enum MACaptionAppearanceDisplayType

A value used to specify the type of captions to be displayed.

enum MACaptionAppearanceBehavior

A value used to indicate the preferred behavior for a preference setting.

enum MACaptionAppearanceFontStyle

A value used to specify a font style.

enum MACaptionAppearanceTextEdgeStyle

A value used to specify detail added to the outside of the text.

Audio Track Characteristics

A value used to indicate preferences for audio tracks.