Applies to all synchronized media technologies that allow synchronization of multiple video streams
The objective of this technique is to allow users who cannot hear or read text rapidly to be able to access synchronized media material without affecting the presentation of the material for all viewers.
For those who communicate primarily in sign language it is sometimes less preferable and sometimes not possible for them to read and understand text at the rate it is presented in captions. For these latter individuals it is important to provide sign language presentation of the audio information.
This technique accomplishes this by providing the sign language interpretation as a separate video stream that is synchronized with the original video stream. Depending on the player, this secondary video stream can be overlaid on top of the original video or displayed in a separate window. It may also be possible to enlarge the sign language interpreter separately from the original video to make it easier to read the hand, body and facial movements of the signer.
NOTE: Since sign language is not usually a signed version of the printed language, the author has to decide which sign language to include. Usually the sign language of the primary audience would be used. If intended for multiple audiences, multiple languages may be used. See advisory technique for multiple sign languages.
Example 1: A university provides a synchronized sign language interpreter video stream that can be displayed, at the viewer's option, along with any of their education programs.
Guidelines for the Production of Signing Books
Useful information about how to display the sign language interpreter in relation to the original synchronized media content is provided in Chapter 13, "Editing".
These techniques may need to be adapted for Web-based presentation.