Web Accessibility Criteria - Captioning


Captions are text alternatives to time-based media that allow people who do not have access to sound to engage with video and audio content. Captions are required for all prerecorded and live time-based media that is published on a website. Captions can come in the following formats: 

  • Closed captioning are captions that can be turned off and on by the user.
  • Open captioning are captions that remain on screen and cannot be turned off.

Why are Captions Important? 

Captions permit users to interact with videos in alternative formats. Captions benefit a variety of users who: 

  • Are deaf or hard of hearing
  • Have cognitive disabilities
  • Are non-native speakers
  • Are visual learners

Captions ultimately will make it easier for all users to interpret what is being said. In cases where the audio quality that is poor (e.g. background noise), users find it difficult to understand what is being said in the media file when captions are present as they will be able to fill in information that they are unable to hear. 

NOTE: CSUN has a policy regarding captions. To learn more about this policy go to UDC's Captioning webpage

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 Best Practice

  • All videos require captions!
  • Always manually input the captions instead of relying on auto-generated captions. Automatic captions typically display inaccurate information. Sound quality, accents or mispronunciations usually affect automatic captions and cause the wrong text to be displayed.  
  • Time management when developing interactive media alternatives is critical. When creating an interactive media file, it is best to consider accessibility from the beginning. It takes time to generate media files and adding the alternative descriptions during development will streamline the process.
  • Include adjustable features for captions. Users should be able to adjust the captions size, font, and color contrast.
  • In HTML5, the track element allows for specific subtitles for a video. It will enable the content creator to have control over the language and subtitle information.

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The example below is an example of a video with captions. The captions in the video can be turned on and off.

(Derived from: YouTube- Captioning Example Using video about Coffee) 

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 Testing Methods 

If a video is present on a website, verify that: 

  1. Captions are present in the video
  2. The captions are in sync with the video
  3. The captions are not Auto-generated. 

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 WCAG 2.1 and References