See Understanding Techniques for WCAG Success Criteria for important information about the usage of these informative techniques and how they relate to the normative WCAG 2.0 success criteria. The Applicability section explains the scope of the technique, and the presence of techniques for a specific technology does not imply that the technology can be used in all situations to create content that meets WCAG 2.0.
Any technology that supports audio and video.
This technique relates to:
The objective of this technique is to provide a second version of video content that provides extended audio descriptions. One of the difficult things about creating traditional audio descriptions is that the narrator sometimes has to provide a lot of information during very short pauses in dialogue. Extended audio description temporarily pauses the audio and video to allow critical information to be delivered when pauses in dialogue are insufficient for adequate description.
Providing a second version of the movie with extended audio descriptions will make this content accessible for blind people who need to hear not only the dialogue but also the context and other aspects of the video that are not communicated by the characters' dialogue alone, and for which there is insufficient time during the natural dialogue.
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.
An alternate version of an online video of a family escaping from a burning building: there is a continuous dialogue between the husband and wife about where the children are. Meanwhile, in the background, a wall caves in. This is important information in the story because it will block their exit from that part of the building. The video track halts (same frame is repeated) while a narrator gives the details about the wall falling and the video continues.
A training film has narrative that runs almost continuously throughout. An alternate version is available for people who have difficulty viewing the video portion. The alternate version freezes the video and provides audio description of key information.
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Open the version of the movie that includes extended audio descriptions.
Check that the video halts for extended audio description when there is not enough space to include necessary narration between the natural dialogue.
Check that the necessary information is in the audio description.
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.
Checks #2, #3 and #4 are true.
If this is a sufficient technique for a success criterion, failing this test procedure does not necessarily mean that the success criterion has not been satisfied in some other way, only that this technique has not been successfully implemented and can not be used to claim conformance.