Terry Thompson
Technology Specialist
AccessIT, University of Washington tft@u.washington.edu
Definitions
Caption - Text representations of audio content within a multimedia
presentation; required in order to make multimedia accessible to people who are
unable to hear the audio. Unlike a transcript, caption text is synchronized
with the video.
Open captions - Captions that are integrated into the video stream. These
are always visible, and can not be turned off.
Closed captions - Captions that are contained within a separate track,
and can be turned on or off.
MAGpie - A free software tool that supports the captioning of digital video
files.
SMIL - "Synchronized Multimedia Integration Language", a W3C standard markup
language that can be used for adding captions to digital video
SAMI - "Synchronized Accessible Media Interchange" is Microsoft's answer
to SMIL
Who Benefits From Captions?
People who are deaf or hard of hearing
People in noisy environments (airports, gyms, sports bars)
People in noiseless environments (computer labs, home with others who don't
want to be distrated)
Turn captions on in Real Player using Tools > Preferences > Content
Overview: Quicktime Files
Uses SMIL, and a QTText caption file
To display captioned video, open the SMIL file
QuickTime Player doesn't support turning captions off.
Some developers created a CC button "wired sprite" using LiveStage Pro.
Overview: Windows Media Files
Uses SAMI (which includes caption text)
To display captioned video, open the original media file. SAMI
file must have the same name, and be stored in the same directory as the
original media file. OR...
Reference the SAMI file in URL. Example: mms://mydomain.com/media.asf?SAMI=http://mydomain.com/media.sami
