Guide to Guideline 1.2 Level 1 Success Criterion 2

Key terms and important concepts

audio description

Additional audio narration that explains important details that cannot be understood from the main soundtrack alone. During pauses in dialog, audio descriptions of video provide information about actions, characters, scene changes and on-screen text to people who are blind or visually impaired.

multimedia

For the purposes of these guidelines, multimedia refers to combined audio and video presentations. It also includes audio-only and video-only presentations that include interaction.

Intent of this success criterion

The intent of this success criterion is to provide people who are blind or vision impaired access to a multimedia presentation. The audio description augments the audio portion of the presentation with the information needed when the video portion is not available.

Techniques for addressing 1.2 L1 SC2

The following combinations of techniques are deemed to be sufficient by the WCAG Working Group for meeting success criterion 1.2 L1 SC2.

Use a technology-specific technique to create an audio description for the multimedia content AND @@do we need conditions or discussion on how to write good audio descriptions?

Technology-Specific Techniques for 1.2 L1 SC2

Audio Descriptions in SMIL 1.0

Provide an audio description audio track with the video track.

Video with audio description.

<smil xmlns="http://www.w3.org/TR/REC-smil">

<head>
   <layout>
     <root-layout background-color="black" height="266" width="320"/>
     <region id="video" background-color="black" top="26" left="0" height="144" width="320"/>
   </layout>
</head>

<body>	
   <par>
     <video src="movie.rm" begin="00:00.0" region="video" title="video"/>             
     <audio src="audiodesc.rm" title="audio description" title="video"/>
   </par>	  
</body>

</smil>

Audio Descriptions in SMIL 2.0

Provide an audio description audio track with the video track.

Video with audio description.

<smil xmlns="//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="movie.rm" region="video" title="video"/>
	<audio src="desc.rm" begin="33.71s"/>
  </par>
</body>

</smil>

Common Failures Identified by the Working Group

The following are common mistakes which are considered failures of this success criterion by the working group.

Optional Techniques (Advisory) for 1.2 L1 SC2

Although not required for conformance, the following additional techniques should be considered in order to make content more accessible. Not all techniques can be used or would be effective in all situations.

Additional SMIL 1.0 Techniques (Advisory)

Provide audio descriptions in multiple languages by using the system-language attribute set to the language name of the language used in each audio track.

Video with multiple language options for audio descriptions.

<smil xmlns="http://www.w3.org/TR/REC-smil">

<head>
   <layout>
     <root-layout background-color="black" height="266" width="320"/>
     <region id="video" background-color="black" top="26" left="0" height="144" width="320"/>
   </layout>
</head>

<body>	
   <par>
     <switch>
       <audio src="audiodescde.rm" system-language="de" />
       <audio src="audiodescen.rm" />
     </switch>

     <video src="movie.rm" begin="00:00.0" region="video" title="video"/>
   </par>	  
</body>

</smil>

Additional SMIL 2.0 Techniques (Advisory)

Provide audio descriptions in multiple languages by providing audio tracks with the systemLanguage attribute set to the language name of the language used.

Video with multiple language options for audio descriptions

<smil xmlns="//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>
     <switch>
       <audio src="audiodescde.rt" begin="33.71s" systemLanguage="de"/>
       <audio src="audiodescen.rt" begin="33.71s" />
     </switch>

     <video src="movie.rm" region="video" title="video"/>
  </par>
</body>

</smil>

Benefits: How 1.2 L1 SC2 helps people with disabilities

People who are blind or have low vision as well as those with cognitive disabilities who have difficulty interpreting visually what is happening benefit from audio descriptions of visual information.

Examples of 1.2 L1 SC2

A movie with audio description.
Transcript of audio based on the first few minutes of, "Teaching Evolution Case Studies, Bonnie Chen" (copyright WGBH and Clear Blue Sky Productions, Inc.)
Describer: A title, "Teaching Evolution Case Studies. Bonnie Chen." Now, a teacher shows photographs.
Bonnie Chen: These are all shot at either the Everglades...for today you just happen to be a species of wading bird that has a beak like this."
Describer: She hands them each two flat, thin wooden blades

Table of Contents

Top