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Technique G9:Creating captions for live synchronized media

About this Technique

This technique is Sufficient to meet 1.2.4: Captions (Live), if combined with G93: Providing open (always visible) captions and Sufficient to meet 1.2.4: Captions (Live), if combined with G87: Providing closed captions and Sufficient to meet 1.2.4: Captions (Live), if combined with G87: Providing closed captions, using a more specific technique. .


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.



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

Expected Results

  • Check #1 is true.
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