G159: Providing an alternative for time-based media for video-only content | WAI | W3C Skip to content

Technique G159:Providing an alternative for time-based media for video-only content

About this Technique

This technique relates to:

This technique applies to all technologies.

Description

The purpose of this technique is to provide an accessible alternative way of presenting the information in a video-only presentation.

In a video-only presentation, information is presented in a variety of ways including animation, text or graphics, the setting and background, the actions and expressions of people, animals, etc. In order to present the same information in accessible form, this technique involves creating a document that tells the same story and presents the same information as the prerecorded video-only content. In this technique, the document serves as a long description for the content and includes all of the important information as well as descriptions of scenery, actions, expressions, etc. that are part of the presentation.

If a screenplay for the video-only content was used to create the content in the first place, this can be a good place to start. In production and editing however, the final version often varies somewhat from the screenplay. To use the screenplay, it would need to be corrected to match the final edited form of the video-only presentation.

Examples

  • An animation shows how to assemble a woodworking project. There is no audio, but the animation includes a series of numbers to represent each step in the process as well as arrows and picture-in-picture highlights illustrating how the assembly is completed. It also includes short outtake animations illustrating what will happen if assembly is done incorrectly. A text alternative that identifies the video-only content reads, "Breadbox assembly video (text description follows)," and the text description of the video includes a full text description of each step in the video.

Tests

Procedure

  1. View the video-only content while referring to the alternative for time-based media.
  2. Check that the information in the transcript includes the same information that is in the video-only presentation.
  3. If the video includes multiple people or characters, check that the transcript identifies which person or character is associated with each action described.

  4. Check that at least one of the following is true:

    1. The transcript itself can be programmatically determined from the text alternative for the video-only content
    2. The transcript is referred to from the programmatically determined text alternative for the video-only content
  5. If the alternate version(s) are on a separate page, check for the availability of link(s) to allow the user to get to the other versions.

Expected Results

  • All of the above checks are 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.

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