Technique SM7:Providing audio description in SMIL 2.0

About this Technique

This technique relates to:

1.2.3 Audio Description or Media Alternative (Prerecorded) (Sufficient when used with G173: Providing a version of a movie with audio descriptions)
1.2.5 Audio Description (Prerecorded) (Sufficient when used with G173: Providing a version of a movie with audio descriptions)

This technique applies whenever SMIL 2.0 player is available.

Techniques are examples of ways to meet Web Content Accessibility Guidelines (WCAG). They are not required to meet WCAG. Content can satisfy the normative requirements of WCAG even if it does not use any of the documented techniques. See About WCAG Techniques.

Description

The objective of this technique is to provide a way for people who are blind or otherwise have trouble seeing the video in audio-visual material to be able to access the material. With this technique a description of the video is provided via audio description that will fit into the gaps in the dialogue in the audio-visual material.

Examples

Example 1: SMIL 2.0 audio description sample for RealMedia player

<smil xmlns="https://www.w3.org/2001/SMIL20/Language">
<head>
  <layout>
    <root-layout backgroundColor="black" height="266" width="320"/>
    <region id="video" backgroundColor="black" top="26" left="0" 
     height="144" width="320"/>
  </layout>
  </head>
  <body>
    <par>
      <video src="salesdemo.mpg" region="video" title="Sales Demo" 
      alt="Sales Demo"/>
      <audio src="salesdemo_ad.mp3" begin="33.71s" title="audio description" 
      alt="Sales Demo Audio Description"/>
    </par>
  </body>
</smil>

The example shows a par segment containing an audio and a video tag. The audio stream is not started immediately.

Related Resources

No endorsement implied.

Tests

Procedure

Find method for turning on audio description from content/player (unless it is always played by default)
Play file with audio description
Check whether audio description is played

Expected Results

#3 is true