Techniques for WCAG 2.0

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G9: Creating captions for live synchronized media

Important Information about Techniques

See Understanding Techniques for WCAG Success Criteria for important information about the usage of these informative techniques and how they relate to the normative WCAG 2.0 success criteria. The Applicability section explains the scope of the technique, and the presence of techniques for a specific technology does not imply that the technology can be used in all situations to create content that meets WCAG 2.0.


Applies to all technologies that present audio visual information.

This technique relates to:


The objective of this technique is to allow users who cannot hear to be able to access real-time synchronized media broadcasts. It is more difficult to create accurate real-time captions because there is little time to correct mistakes or to listen a second time or consult someone to be sure the words are accurately reproduced. It is also harder to simplify or paraphrase information if it is flowing too quickly.

Real-time typing text entry techniques exist using stenographic and rapid typing technologies. Re-voicing speech-to-text (where a person listens to speech and then carefully re-voices it into a computer trained to their speech) is used today for telephone relay services and may be used in the future for captioning. Eventually speech-to-text with correction will be possible.


Example 1

A television studio uses a real-time captioning service to create captions for its evening news online.

Example 2

A user watches an online seminar on their mobile device, including captioning provided through the use of Communication Access Real-time Translation (CART). The captions provided also benefit in-person participants who need captioning and can view the information on their own device.


No resources available for this technique.



  1. Check that a procedure and policy are in place to ensure that captions are delivered in real-time.

Expected Results

If this is a sufficient technique for a success criterion, failing this test procedure does not necessarily mean that the success criterion has not been satisfied in some other way, only that this technique has not been successfully implemented and can not be used to claim conformance.