Captions

• Captions SHOULD be synchronized with the multimedia content.
• Multimedia content SHOULD have accurate captions containing the spoken audio.
• Captions CAN be avoided if the content in the video is already covered as plain text on the webpage.
• If a button is used to display/hide the captions, the button itself MUST be accessible as well. For more information, refer to the Toggle Buttons component.
• The caption text MUST meet the contrast requirements as below:
  • If standard text is used, the color contrast ratio SHOULD be 4.5:1 between the foreground and the background text.
  • If large text i.e., 18pts or 14pts with bold is used, the color contrast ratio SHOULD be 3:1 between the foreground and the background text.

• Live captions SHOULD contain additional important things such as Presenter’s cue, important sound effects, and dialogue.

• Pre-recorded captions SHOULD contain additional important things such as important sound effects, identifying speakers and dialogue.
• Pre-recoded captions CAN be implemented as open or closed captions.
  • Open captions are always in view, and it cannot be turned off.
  • Closed captions can be turned on or off using a control.
• The best practice is to provide closed captions instead of open captions for any multimedia content.
• For all pre-recorded multimedia content, a full text transcript and captions SHOULD be provided.

Well-defined captions benefits majorly the below users.

• People with hearing impairments.