1. Perceivable

1.2 Time-Based Media (Level AA)

Success Criterion 1.2.4 Captions (Live)

Level AA

Captions are provided for all live audio content in synchronized media.

Key Point: Captions for live content, though a Level AA requirement in WCAG 2.1, is an exception for AODA. While they are not required to comply with AODA, they are recommended, where feasible, to reach the widest possible audience. In jurisdictions other than Ontario, captions for live content may be required.

Captions (Live) Explained

People who are deaf or hard of hearing can watch real-time presentations by reading captions.

Captions identify who is speaking and what they are saying, plus other information conveyed through sound effects, music, and other sounds.

At present, human transcribers type the captions for real-time presentations. In the future, speech recognition technology may make it possible to automatically generate captions in real time.

Example: CBC News Live Captions

Suggested Reading: How are live captions delivered? See AI Live, for live captioning services and how it works and potential benefits for others who are not hearing impaired.

Suggested Reading:

Success Criterion 1.2.5 Audio Description (Prerecorded)

Level AA

Audio description is provided for all prerecorded video content in synchronized media.

Audio Description (Prerecorded) Explained

This is a slightly more stringent version of SC 1.2.3, which gives authors the option to provide an audio description or a full text alternative in a synchronized media presentation. If authors do one or the other, they are conforming at Level A.

SC 1.2.5 tells authors how to conform at Level AA: they must provide an audio description, a requirement already met if they chose that alternative for SC 1.2.3.

To conform to Level AAA, authors must include an extended audio description. This is covered in SC 1.2.7.

No audio description is necessary if all video track information is already provided in the audio track.

Suggested Reading:

Video: Audio Description on YouTube

© James Rath. Released under the terms of a Standard YouTube License. All rights reserved.

Key Point: Audio description for prerecorded video, though a Level AA requirement under WCAG 2.1, is an exception under AODA for non-government organizations. Only Government of Ontario organizations are required to provide audio description for video by January 1, 2020. Non-government organizations should refer to SC 1.2.3 and provide a transcript that includes descriptions.

Suggested Reading: Have a look at the audio described shows/movies available on Netflix: Netflix Audio Described Titles.

Suggested Reading:


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Introduction to Web Accessibility Copyright © 2019 by The Chang School, Toronto Metropolitan University is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License, except where otherwise noted.

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