Technique H95:Using the `track` element to provide captions

About this Technique

This technique relates to 1.2.2: Captions (Prerecorded) (Sufficient when used with G87: Providing closed captions).

This technique applies to HTML.

Description

The objective of this technique is to use the HTML track element to specify a captions timed text track for a video element. Caption timed text tracks contain transcription or translation of the dialogue, sound effects, relevant musical cues, and other relevant audio information, suitable for when sound is unavailable or not clearly audible.

The src attribute of the track element is a URL that is the address of the text track data.

The kind attribute of the track element indicates the kind of information in the timed text. captions text tracks provide a text version of dialogue and other sounds important to understanding the video. Subtitles contain only the dialogue. If other audio information is important to understanding the video, a subtitle track will not be sufficient to meet the success criterion.

Note

Some regions use the term "subtitle" for any visible text representation of the audio track. An author may mark up a timed text track in the language of the audio track as kind=subtitles, instead of kind=captions, and may include additional relevant audio information. It is not best practice to use subtitles in this situation, since it may confuse users who are trying to find captions, but such a timed text track would meet the requirements of Success Criterion 1.2.2.

Examples

Example 1: Captions in one language

A video element for a video in the English language with an English caption track. The captions are provided in the WebVTT format.

<video poster="myvideo.png" controls>
  <source src="myvideo.mp4" srclang="en" type="video/mp4">
  <track kind="captions" label="English" src="myvideo_en.vtt" srclang="en">
</video>

Example 2: Captions in multiple languages

A video element for a video in the English language with an English caption track. The captions are provided in the WebVTT format.

<video poster="myvideo.png" controls>
  <source src="myvideo.mp4" srclang="en" type="video/mp4">
  <source src="myvideo.webm" srclang="fr" type="video/webm">
  <track kind="captions" label="English" src="myvideo-en.vtt" srclang="en">
  <track kind="captions" label="Français" src="myvideo-fr.ttml" srclang="fr">
</video>

Related Resources

No endorsement implied.

Tests

Procedure

For each video element used to play a video:

Check that the video contains a track element of kind captions in the language of the video.

Expected Results

Check #1 is true.

Test Rules

The following are Test Rules related to this Technique. It is not necessary to use these particular Test Rules to check for conformance with WCAG, but they are defined and approved test methods. For information on using Test Rules, see Understanding Test Rules for WCAG Success Criteria.