1.2: Time-based Media
Guideline 1.2: Provide alternatives for time-based media.
Time-based media may consist of audio or video materials, or a combination of both. It also includes audio and video materials which require user interaction. Guideline 1.2 closely relates to guideline 1.1 as essentially you are required to provide text alternatives for time-based media as well.
1.2.1: Audio-only and Video-only (Prerecorded) (Level A)
For prerecorded audio-only and prerecorded video-only media, the following are true, except when the audio or video is a media alternative for text and is clearly labeled as such: (Level A)
- Prerecorded Audio-only: An alternative for time-based media is provided that presents equivalent information for prerecorded audio-only content.
- Prerecorded Video-only: Either an alternative for time-based media or an audio track is provided that presents equivalent information for prerecorded video-only content.
When you post audio tracks on your web site, make sure it has a text equivalent, so those who cannot hear can still benefit from the information.
When you post a video on your site, make sure that the information found on the video is available either by using an audio track, or a transcript. This helps those who cannot see the video, or those with a cognitive disability.
Alternative is not required
When an audio or a video presentation is provided as an alternative of other materials, the above do not apply. For example, when you post a video on your web site, and create an audio-only alternative. This audio track does not require another alternative, however, it is necessary to clearly state that this audio track is an alternative for the video.
1.2.2: Captions (Prerecorded) (Level A)
Captions are provided for all prerecorded audio content in synchronized media, except when the media is a media alternative for text and is clearly labeled as such. (Level A)
When you post audio content to complement a page, it is required to provide captions. As discussed earlier, do not confuse captions with subtitles. Captions contain more information than the transcript of spoken text.
There are two exceptions when captions are not required:
- When the audio does not add any further information to the text displayed on the web page.
- When the audio is already an alternative for another presentation.
However, in these instances you need to clearly indicate that there is audio on the site and that it is already an alternative of other information.
1.2.3: Audio Description or Media Alternative (Prerecorded) (Level A)
An alternative for time-based media or audio description of the prerecorded video content is provided for synchronized media, except when the media is a media alternative for text and is clearly labeled as such. (Level A)
When a video is embedded into your web site which complements the information you are presenting, you have to provide an alternative.
This success criterion allows you two options: either to provide an audio description, or a text equivalent of the video.
Similarly to other success criteria, you do not have to provide an alternative, when the video content as an alternative for text, but in this case you have to clearly indicate it.
1.2.4: Captions (Live) (Level AA)
Captions are provided for all live audio content in synchronized media. (Level AA)
You have to provide captioning for all live media. Anything that is broadcasted on a web site real time, needs to have captioning without an exception.
This success criterion presently cannot be fulfilled by the use of technology only. An actual human is required to provide the captioning which you need to incorporate into your web site.
1.2.5: Audio Description (Prerecorded) (Level AA)
Audio description is provided for all prerecorded video content in synchronized media. (Level AA)
This success criterion is closely related to 1.2.3. The difference is in the level of conformance. 1.2.3 has a Level A conformance, where to meet minimum requirements, an audio description or alternative text can be used. 1.2.5 goes one step further to provide a higher level of accessibility with audio description, which puts it into a Level AA category.
1.2.6: Sign Language (Prerecorded) (Level AAA)
Sign language interpretation is provided for all prerecorded audio content in synchronized media. (Level AAA)
While a text alternative or captioning for audio content provides a level of accessibility, providing sign language interpretation for audio materials includes even more people. As minimal accessibility is established in Level A and AA criteria, sign language interpretation is categorized as Level AAA, as the highest level of accessibility.
While many people are comfortable reading text, they can be more efficient understanding sign language. Also, it might just be a personal preference. Different people have their own preference whether they prefer written text or audio, it is the same idea with sign language.
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. (Level AAA)
Similar to sign language, the minimal criteria for accessibility is met in Level A and AA success criteria. However, to provide further information and consider personal preference, the highest level of accessibility requires to provide more detailed audio description for synchronized media where the pauses are not sufficient to describe all visual information.
Think about a scene which you just glance at, and receive lot's of information. The buildings, nature and objects which are present. It may take several minutes to explain what you can process in the matter of seconds.
In such instances, you can freeze the video to provide the necessary explanation and continue showing the video content. However, for those who do not need this service, it might be confusing and annoying. Therefore, it is a good practice to make extended video description selectable.
1.2.8: Media Alternative (Prerecorded) (Level AAA)
1.2.8:An alternative for time-based media is provided for all prerecorded synchronized media and for all prerecorded video-only media. (Level AAA)
All recorded media should have an alternative option. The way it differs from previous success criteria is that all information should have an alternative. Visual information should be explained, audible information should be transcribed or captioned. Essentially, all information should be available in a text format, so people, who cannot hear or see, should still be able to use assistive technologies to interpret content to them.
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. (Level AAA)
This criterion is very similar to 1.2.4, except beyond captioning, a complete description of all information is required. This information should be available in text format.