This is a DRAFT resource that supports Working Drafts of WCAG 3. Content in this resource is not mature and should not be considered authoritative. It may be changed, replaced or removed at any time.

🔙 WCAG 3.0 (Silver) Guidelines (Captions)

Method: Provides text equivalents of speech and non-speech audio

Platform

Technology

Applies to technologies that support audio synchronized with visual information including media and immersive environments.

Summary

People who cannot use the audio track need to know what is said, who is saying it and the relevant sound effects to provide an equivalent experience as sighted users.

How it solves user need

People who cannot use the audio track need to know what is said, who is saying it and the relevant sound effects to provide an equivalent experience as sighted users.

Outcome and Functional Categories

This method supports the outcome Outcome 1: Captions are used to understand speech.

Technical description

The objective of this technique is to provide a way for people who have hearing impairments or otherwise have trouble hearing the dialogue in synchronized media material to be able to view the material and see the dialogue and sounds - without requiring people who are not deaf to watch the captions. With this technique all of the dialogue and important sounds are embedded as text in a fashion that causes the text not to be visible unless the user requests it. As a result they are visible only when needed. This requires special support for captioning in the user agent. [Note: From G87]

See the BBC Subtitle Guidelines for advice on best practices for captioning.

W3C has best practices for captioning in the Timed Text Markup Language 2 (TTML2)

Dependencies

None.

Example 1 - Captions in media

<scene> Humphrey Bogart sits at desk and phone rings </scene>
<scene> [Ringing phone] <scene>

The use of square brackets denotes this text as an audio description of the action in the scene.

<scene> Humphrey Bogart answers the phone. </scene>
<scene> [Lauren Bacall says:  You're making dinner tonight] </scene>
<scene> Humphrey Bogart says: No way,  someones gotta pay the bills </scene>	
<scene> [Gun shot] </scene>
<scene> Humphrey drops phone from hand </scene>
<scene>[Lauren Bacall says: No dinner tonight for you my dear.</scene>

Example 2 - Captions in an immersive environment

In an online “first-person shooter” game, players have the option to enable and customize captions. A popular option is to vertically shrink the default view-port, so as to fit two lines of real-time captioning text below the weapon and health bar. The captioning includes environmental cues and speech from Non-Player Characters (NPC) avatars of allies and foes.

Atomic Tests

Video element auditory content has accessible alternative

Unit Tested:All multimedia

Measurement: Average rating of all multimedia in a view

Procedure for each test:

Turn on the closed caption feature of the media player
View the synchronized media content with the closed caption feature turned on
Check that the captions can be turned on and off
- Closed captions can be turned on and off
- Open captions cannot be turned off

Rating:

Each video with no captions is rated a 0
Each video with open captions is rated a 1
Each video with closed captions is rated a 2

We want public feedback about whether Open Captions (burned in captions) pass for Bronze level. Open captions are not text and cannot be customized for people with low vision or routed to a braille display for people who are blind-deaf.