Change Captions preferences for accessibility on Mac
On your Mac, use the Captions pane of Accessibility preferences to control how subtitles are styled, and whether to use closed captions instead, when they’re available.
To change these preferences, choose Apple menu 
Option | Description |
|---|---|
Styles list | Available built-in styles (Transparent Background, Classic, Large Text, Outline Text), and styles that you added. To edit the settings for a style you added, select the style in the list, then click Edit. |
Add | Create a style or delete one that you added. A new style inherits the settings of the style that’s selected when you click Add. If you like many of the settings of an existing style, select it before you click Add, then change just the settings you don’t like. |
Prefer closed captions and SDH | If they’re available, use closed captions or SDH instead of standard subtitles for content played on your Mac. |
Style settings | Settings for a new style, or one you’re editing. To have your setting always used, deselect its “Allow video to override” checkbox. In the bottom section, you can set the color and size to use for a specific font whenever it’s used in subtitles. |
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Tip: The Outline Text style is especially useful for subtitles and captions that appear in Japanese.