Skip to content

Technique SM13:Providing sign language interpretation through synchronized video streams in SMIL 1.0


Applies whenever SMIL 1.0 player is available

This technique relates to 1.2.6: Sign Language (Prerecorded) (Sufficient when used with G81: Providing a synchronized video of the sign language interpreter that can be displayed in a different viewport or overlaid on the image by the player).


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 1.0, 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.


Example 1: SMIL 1.0 sign-language interpretation sample for QuickTime player

<?xml version="1.0" encoding="UTF-8"?>
<smil xmlns:qt="" 
   xmlns="" qt:time-slider="true">
    <root-layout width="320" height="300" background-color="black"/>
    <region top="0" width="320" height="240" left="0" background-color="black" 
    <region top="240" width="320" height="60" left="0" background-color="black" 
    <video dur="0:01:20.00" region="videoregion" src="" 
     alt="Sales Demo"/>
    <video dur="0:01:20.00" region="signingregion" system-captions="on" 
     src="" alt="Sales Demo Sign Language Interpretation"/>

Other sources

No endorsement implied.



  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

  • #3 is true
Back to Top