1. Perceivable
1.2 Time-Based Media (Level AAA)
Contents
Success Criteria 1.2.6 Sign Language (Prerecorded)
Level AAA
Sign-language interpretation is provided for all prerecorded audio content in synchronized media.
Sign Language (Prerecorded) Explained
American Sign Language (ASL) and other forms of sign language are languages in their own right. For one, they are not based on English. Much like French can be translated to English, ASL can also be translated to English. Some people who are Deaf (with a capital D representing a member of the Deaf community) may rely on ASL to communicate and may understand very little English. Hence, typical English captions may not always be understood effectively by a person who is Deaf.
Some people who are deaf grow up in hearing families and will often learn signed English, learn to read lips, and learn to write in English. As a result, they will understand English captions.
- Sign language allows people who are deaf or hard of hearing to understand the audio track of a synchronized media presentation.
- Sign languages are very rich and convey shades of meanings that are not captured in captions. For this reason, sign language interpretation of synchronized media is considered more equivalent than access via captions.
- Example: A university makes a video of a visiting professor talking to students and faculty and decides to post it online. There is no sign-language interpreter during the original lecture. Afterwards, the university produces a second video of a sign-language interpreter interpreting the professor’s talk. The university “splices” the second video into the corner of the original video.
- Some people who are deaf or hard of hearing are not as fluent in written language as they are in sign language. Conversely, not everybody who is deaf or hard of hearing understands sign language. For this reason, access to synchronized media content is improved by providing sign language as well as captions.
Video: Adding Phosphate to Water (American Sign Language Translation)
© GovSnyder. Released under the terms of a Standard YouTube License. All rights reserved.
Video: Obama Tribute to Nelson Mandela: U.S. President Barack Obama in American Sign Language by Real Interpreter
© Real Interpreter. Released under the terms of a Standard YouTube License. All rights reserved.
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Success Criteria 1.2.7 Extended Audio Description (Prerecorded)
Level AAA
Where pauses in foreground audio are insufficient to allow audio descriptions to convey the sense of the video, extended audio description is provided for all prerecorded video content in synchronized media.
Extended Audio Description (Prerecorded) Explained
- This is similar to SC 1.2.5, which states that authors include audio descriptions in synchronized media presentations. Sometimes there are no (or insufficient) pauses to allow audio descriptions. In these cases, provide extended audio descriptions to convey the sense of the video.
- Extended audio descriptions are done by freezing the presentation at key moments and playing additional audio material. The synchronized media presentation is then resumed.
- Because extended audio descriptions may disrupt viewing for those who do not need them, make it possible to turn the feature on and off. Alternatively, two versions of a presentation, one with extended descriptions and the other without, can be provided.
- Example: An art school owns a film of an influential artist describing her approach, and she digitizes the film for posting online. She speaks rapidly, with few pauses. As she talks, she rapidly draws shapes on a flip chart. After completing each sketch, she flips the flip chart and starts a new drawing, talking all the while.
- To make extended audio descriptions, the video is paused after she completes each drawing, and a narrator describes it and her gestures. The video then resumes.
Video: Vintage TV Commercial for Post GrapeNuts (with extended audio description)
© AccessForEveryone. Released under the terms of a Standard YouTube License. All rights reserved.
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Success Criteria 1.2.8 Media Alternative (Prerecorded)
Level AAA
An alternative for time-based media is provided for all prerecorded synchronized media and for all prerecorded video-only media.
Media Alternative (Prerecorded) Explained
- An “alternative for time-based media” is a method for making audio-visual materials accessible to people who do not see well enough to read captions and who do not hear well enough to listen to dialogue and audio descriptions.
- To create an alternative for time-based media, describe (in writing) all information in the synchronized media (both visual and auditory). This text is the alternative for time-based media. It reads like a book narrative — a running description of everything that happens.
- The alternative for time-based media contains a transcript of all dialogue; descriptions of all visual information (e.g., scene changes, actions, and facial expressions); and descriptions of all non-speech sounds (e.g., laughter, off-screen voices, and background music).
- If the presentation requires user interaction (e.g., buttons labelled “Go to next lesson” at the end of every section), include hypertext links to provide the same functionality.
- These techniques make it possible for people who are deaf-blind to access time-based media using a refreshable Braille display.
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Success Criteria 1.2.9 Audio-Only (Live)
Level AAA
An alternative for time-based media that presents equivalent information for live audio-only content is provided.
Audio-Only (Live) Explained
- To make live events (such as video conferencing, speeches, and radio webcasts) accessible to people who are deaf or hard of hearing, use text alternatives.
- The best text alternative is live text captioning. A trained human operator listens to what is being said and types a verbatim transcript in real time. The operator also adds non-spoken details, such as laughter and applause, that are essential to understanding what is happening.
- If an event follows a script, a transcript prepared in advance is a possibility. However, live captioning is preferred because the operator’s transcript plays out in real time, and the operator can adapt when deviations from the script occur.
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