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.
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.