Concepts & Techniques for Accessible, Closed Captioned Web-Based Video
10th Annual Accessing Higher Ground:
Accessible Media, Web and Technology Conference

Boulder, Colorado
November 7, 2007

http://disability.law.uiowa.edu/lhpdc/publications/kleinpubs.html
Flash
•	Video is played back by Flash Player
•	Version 7 or above of the Flash Player required for the end user
•	Interface (controls, layout) located in .swf file
Flash Video
•	De facto Web standard because of “player wars”
•	Lack of standards compliance
•	Continual, relentless upgrades
•	Difficulty in upgrading – pushing users toward paid versions
•	Hijacking of media types / file extensions
•	People just want video to work
Flash History
•	Becoming more accessible by version 6
•	Full integration with video by version 7
•	Ubiquitous (around 97% share)
•	YouTube, MySpace
•	Handles video well
•	Sorenson Spark codec
•	ON2VP6 codec
•	Fast
•	Developer-level flexibility
•	Can revise interface as needed
•	Control over accessibility (within Flash capabilities)
Captioned Flash Video
•	Flash Video Player (ours)

•	CC for Flash / ccPlayer (National Center for Accessible Media – WGBH)

•	FLVPlayback / FLVPlaybackCaptioning Components for Flash (Adobe)

Flash Video Player
•	Allows captioned video without Flash programming 
•	Open source
•	Major or minor customization possible
•	Flash 7.0 and above
CC for Flash / ccPlayer
•	ccPlayer allows captioned video without Flash programming
•	Flash components
•	Skins
•	Little Flash knowledge needed
•	Closed source, so customization is limited
•	DFXP caption files
•	Flash 8.0 

FLVPlaybackCaptions
•	Flash programming required
•	Minimal Flash knowledge needed
•	Skins
•	Closed source, so customization is limited
•	DFXP caption files
•	Flash 9.0 (CS3)

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
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: Activity 3: Flash Video Player

•	Objective: 
•	Modify an XML file and assemble the QuickTime captions file with the Flash video player to create a web-enabled, 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
•	Or
<param name="base" value= “.">
•	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