Techniques for Creating Accessible, Closed Captioned Web-Based Video
California State University - Northridge
21st Annual International Technology and 
Persons with Disabilities Conference

Los Angeles, California
March 22, 2006

http://disability.law.uiowa.edu/lhpdc/publications/kleinpubs.html
Flash
•	Video is played back by Flash Player
•	Version 7 of the Flash Player in the browser required for the end user
•	Interface (controls, layout) located in .swf file
Flash Video
•	Frustrated with “player wars”
•	Lack of standards compliance
•	Continual, relentless upgrades
•	Difficulty in upgrading – pushing users toward paid versions
•	Hijacking of media types / file extensions
Flash Rationale
•	Becoming more accessible by version 6
•	Full integration with video by version 7
•	Greater installed base
•	Handles video well
•	Fast
•	Developer-level flexibility
•	Can revise interface as needed
•	Control over accessibility (within Flash capabilities)
Flash Files
•	Video
•	.flv
•	Caption file
•	We use the QuickTime caption file
•	XML configuration file
•	Integrates video and caption files
•	Flash player (Shockwave)
•	.swf compiled from Flash code
•	HTML
•	Flash code file (.fla)
•	Optional for further development
Flash Video Player Assembly
•	The Flash playback engine – videoname.swf
•	The video – videoname.flv
•	The caption file – videoname_captions.txt
•	Same caption file as used for QT (or SAMI file is possible)
•	The caption control file – captions.xml
•	Includes URLs to video and captions files
•	User can toggle captions in the video player with CC icon (on by default)
Captions.xml File Characteristics
•	Use XML standards
•	Tags case sensitive
•	All elements closed
•	<tag>xxx</tag> (open and close tags)
•	<tag /> (no explicit close tag; use the slash)
XML Configuration
<?xml version="1.0" encoding="ISO-8859-1"?>
<flashcaptioning>
	<ccconfig>
		<CaptionLocation>captionfile.txt</CaptionLocation>
		<VideoLocation>video.flv</VideoLocation>
		<VideoSizeWidth>240</VideoSizeWidth>
		<VideoSizeHeight>180</VideoSizeHeight>

		<!--Time in seconds -->
		<VideoTotalTime>1948.03</VideoTotalTime>

		<!-- The following is a placeholder -->
		<XMLFileUsed></XMLFileUsed>
	</ccconfig>
</flashcaptioning>
Flash Video Player Activity
•	Handout: Flash captions.xml Activity - Assemble Files

•	Objective: Modify an XML file and assemble the QuickTime captions file with the Flash video player to create a captioned, Flash video.
Flash Video Player Files
•	Place all files together in a folder
•	Video (.flv)
•	Caption file (video_caption.txt)
•	XML file (caption.xml)
•	Flash video player file (.swf)
Flash Security
•	Keep files in same folder when possible
•	Use BASE attribute in HTML
•	<object>
<param name="base" value="http://domain.com/">
</object
•	And
<embed … base="http://domain.com/" … >
•	Test thoroughly, especially among browsers and browser versions
•	More:
•	http://www.macromedia.com/devnet/flash/whitepapers/security.pdf
•	http://www.macromedia.com/devnet/flash/articles/fplayer_security.html