Techniques for WCAG 2.0

Skip to Content (Press Enter)

This document is a draft, and is designed to show changes from a previous version. It is presently showing added text,changed text,deleted text,[start]/[end] markers,and Issue Numbers.

Hide All Edits   |   Toggle Deletions  |   Toggle Issue Numbers   |   Toggle [start]/[end] Markers   |   Show All Edits

Changes are displayed as follows:

-

SM14: Providing sign language interpretation through synchronized video streams in SMIL 2.0

Applicability

SMIL 2.0

This technique relates to:

Description

The objective of this technique is to provide a way for people who are deaf or otherwise have trouble hearing the dialogue in audio visual material to be able to view the material. With this technique all of the dialogue and important sounds are available in a sign-language interpretation video that is displayed in a caption area.

With SMIL 2.0, separate regions can be defined for the two videos. The two video playbacks are synchronized, with the content video displayed in one region of the screen, while the corresponding sign-language interpretation video is displayed in another region.

Examples

Example 1: SMIL 2.0 sign-language video sample for RealMedia player

Example Code:


<smil xmlns="http://www.w3.org/2001/SMIL20/Language">
  <head>
    <layout>
      <root-layout backgroundColor="black" height="310" width="330"/>
      <region id="video" backgroundColor="black" top="5" left="5" 
      height="240" width="320"/>
      <region id="signing" backgroundColor="black" top="250" 
      height="60" left="5" width="320"/>
    </layout>
  </head>
  <body>
    <par>
      <video src="salesdemo.mpg" region="video" title="Sales Demo" 
      alt="Sales Demo"/>
      <video src="salesdemo_signing.mpg" 
      region="signing" systemCaptions="on" 
      title="sign language interpretation" 
      alt="Sales Demo Sign Language Interpretation"/>
    </par>
  </body>
</smil>

The example shows a <par> segment containing two <video> tags. The systemCaptions attribute indicates that the sign language video should be displayed when the user's player setting for captions indicates the preference for captions to be displayed. The <layout> section defines the regions used for the main video and the sign language interpretation video.

Resources

Resources are for information purposes only, no endorsement implied.

Tests

Procedure

  1. Enable control in content or player to turn on sign language interpretation (unless it is always shown)

  2. Play file with sign-language interpretation

  3. Check whether sign language interpretation is displayed

Expected Results

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.