Captions are provided for live multimedia.
On this page:
The purpose of this checkpoint is to ensure that equivalent alternatives are provided for any multimedia presentation, including live multimedia. These equivalent alternatives must be synchronized with the presentation typically through computer assisted real time (CART) captioning, in which an operator listens to the call and repeats the content out loud. At that point, a voice recognition software package trained to their voice creates the live captions.
The checkpoint also allows for equivalent facilitation when open or closed captions cannot be provided. Equivalent facilitation for captioning can be provided via a separate communication channel, such as a third-party transcription service or by having meeting participants use a group chat to transcribe the discussion.
Required development and unit test techniques
To comply with this checkpoint, you must meet the following technique.
- Live captions: Create captions for live multimedia.
Note: The example presented in the technique is not exhaustive. It is meant to illustrate the spirit of this checkpoint.
General example 1
The IBM CFO delivers a quarterly presentation to IBM stockholders broadcast live on IBM.com and a real-time captioning service provides the captions for people who are deaf or hard of hearing.
For additional information, refer to the WCAG 2.0 examples of creating captions for live synchronized media (link resides outside of ibm.com) and Success Criterion 1.2.4 examples of creating live captions (link resides outside of ibm.com).
Required unit tests for general development technique 1
Manually perform the following unit tests.
- Locate the live multimedia object.
- Before the broadcast, verify that you have a process to provide real-time captioning of audio and video content for the live broadcast.
During the broadcast, monitor the broadcast to ensure that the delivery of captions actually happens in real-time.
Recommended development techniques
Although you do not have to implement the recommended techniques in order to comply with this checkpoint, you should review them because they can improve the accessibility and usability of the application.
The recommended development techniques for this checkpoint are as follows:
- Ensure your captions adhere to the standard captioning guidelines.
- Provide a note saying "No sound is used in this clip" for video-only clips.
- Use SMIL 1.0 to provide captions for all languages included in the audio tracks.
- Use SMIL 2.0 to provide captions for all languages included in the audio tracks.
- Provide a pop-up text window for a short audio presentation.
Recommended development example 1
Captions should adhere to the following guidelines:
Note: Examples for recommended techniques 2-6 are still under development by the WCAG 2.0 Working Group.
©2011 IBM Corporation
Last updated July 1, 2011.
W3C Recommendation 11 December 2008: http://www.w3.org/TR/WCAG20/ (link resides outside of ibm.com)
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