Understanding Extended Audio Description (Prerecorded)

In brief

Goal

Videos can be played with more detailed audio descriptions.

What to do

Provide extended spoken descriptions of the visual content in videos.

Why it's important

People who are blind or who cannot understand the visual content can have it described to them while playing videos.

Intent of Extended Audio Description (Prerecorded)

The intent of this Success Criterion is to provide people who are blind or visually impaired access to a synchronized media presentation beyond that which can be provided by standard audio description. This is done by periodically freezing the synchronized media presentation and playing additional audio description. The synchronized media presentation is then resumed.

Because it disrupts viewing for those who do not need the additional description, techniques that allow you to turn the feature on and off are often provided. Alternately, versions with and without the additional description can be provided.

Benefits of Extended Audio Description (Prerecorded)

• People who are blind, people with low vision who cannot see the screen, as well as those with cognitive limitations who have difficulty interpreting visually what is happening, often use audio description of the visual information. However, if there is too much dialogue the audio description is insufficient. Extended audio description can provide the additional information needed to understand the video.

Examples of Extended Audio Description (Prerecorded)

• Example 1. Video of a lecture. A physics professor is giving a lecture. The professor makes freehand sketches on the whiteboard, speaking rapidly while drawing. As soon as discussion on one problem is finished, the professor erases the drawing and makes another sketch while continuing to speak and gesture. The video is paused between problems, and extended audio description of the professor's drawings and gestures is provided; the video is then resumed.

Resources for Extended Audio Description (Prerecorded)

• Synchronized Multimedia Integration Language (SMIL) 1.0
• Synchronized Multimedia Integration Language (SMIL) 2.0
• Accessibility Features of SMIL
• NCAM Rich Media Accessibility, Accessible SMIL Templates
• Standard Techniques in Audio Description

Techniques for Extended Audio Description (Prerecorded)