Accessibility Issues
in Multimedia and on the Web
Kate Stepp
Regulations Regarding Accessibility
in the United States
Section 508 of the Rehabilitation Act
This requires that Federal agencies and their contractors give disabled
employees and members of the public access to information (including
web sites) that is comparable to the access available to others.
Americans with Disabilities Act of 1990
This prohibits discrimination on the basis of disability.
Section 225 of the Telecommunications Act of 1996
This requires suppliers to make telecommunications products and
services accessible unless not requiring significant difficulty or expense.
Accessibility Problems with Multimedia:
Related to Vision
• Images or video without text or audio descriptions
• Unsynchronized, or overlapping audio descriptions
• No text/audio available for links
• Text cannot be identified in images
• Fixed color contrast, font size etc.
• Magnification makes a mess
Information collected from: World Wide Web Consortium (www.w3.org)
Accessibility Problems with Multimedia:
Related to Hearing
• Audio without captions
• Unsynchronized captions
Information collected from: World Wide Web Consortium (www.w3.org)
Accessibility Problems with Multimedia:
Related to Motor/Mobility
• Inability to use hands
• Muscle tremors / Loss of muscle control
Information collected from: World Wide Web Consortium (www.w3.org)
Accessibility Problems with Multimedia:
Cognitive disabilities
• Fixed pace of presentation
• Unclear structures, complicated navigation
• Complex overlays of content e.g. audio streams
Information collected from: World Wide Web Consortium (www.w3.org)
SMIL
Synchronized Multimedia Integration Language
W3C Recommended XML markup language for describing multimedia presentations
(developed in 1997)
Defines markup for:
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timing
layout
animations
visual transitions
media embedding
SMIL Tags
<par> - parallel
<seq> - sequential
SVG
Scalable Vector Graphics
XML specification and file format for describing two-dimensional vector graphics,
both static and animated
(developed between 1999-2000)
SVG
Online Shopper with Color Blindness
Issues
• cannot distinguish between red text for sale prices
• cannot distinguish which fields are required in a form
that indicates them with red text
Possible Solutions
• redundant information for color
• such as also printing color names for products
• including symbols such as asterisks for required fields
Best Technical Solutions
• use style sheets for color information so that users can override
color information with colors that suite their eyesight
Reporter with Repetitive Stress Injury
Issues
• RSI has made it painful for this user to type or use the mouse
• (the user gets by using speech recognition and a modified keyboard)
• Needs to publish stories to the web, but cannot use a mouse to
manipulate the authoring tool fully
• Needs to surf the web, but tabbing through links by voice is slow and
sometimes inaccurate
Solutions
• software designed with full keyboard support
• an access key feature on websites allowing links to have direct
keyboard shortcuts
Online Student who is Deaf
Issues
• some online education material is in the form of audio lectures
Solutions
• although transcripts of the audio is one solution,
a better solution would be to use SMIL to synchronize captions
of the audio with the video
Added Perks
• having synched captioned audio/video also makes the material
more useful for those who are not handicapped by making it easier
to search the audio text and locate a precise position in the lecture
Blind User who wants to Surf the Web
Issues
• cannot read text visually
• cannot see images, or text that is in the form of graphic
• cannot navigate as most users do -> using vision to click links
Solutions
• screen readers can read text to a blind user using audio output
• refreshable Braille output can also provide a way for the blind to read the screen
• to navigate, the user can tab through links assuming they are properly labeled
for the screen reader
• alternative text for images (can be contained in html “alt” attribute)
• clearly marked column and row headers for tables
Web User with Cognitive Disability
Issues
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page time-outs occur when user is still trying to understand site
animations are too fast without controller options
complex styles and graphics make text difficult to read and understand
sounds and effects are distracting
navigation can be confusing
Solutions
• give generous page time-out limits for complicated forms or pages
• make sure all animated multimedia objects have controllers that allow
the user to navigate the movie and adjust the speed
• be sure any complicated diagrams or images use the alt feature to allow
screen readers to access the information
• all sound effects should be optional – users should be able to turn them
on or off
• have a simplified navigation menu for the most common links, and maintain
a common navigational structure throughout site
How can a blind user navigate links?
How can a screen reader help those who
are blind and deaf?
If the screen reader reads the text to the
user, how do they skip around in a document?
Mouse Alternatives
Eye Gaze Software
Mouse Alternatives
NoHands Mouse
Mouse Alternatives
"Sip-N-Puff", Mouth controlled Joysticks
Evaluating a Site for Accessibility
http://webxact.watchfire.com/
http://www.wave.webaim.org/index.jsp