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Presenter(s)
Jared Smith
WebAIM (Web Accessibility in Mind)
Center for Persons with Disabilities
Utah State University
United States
Email: jared@cpd2.usu.edu
Abstract: Instructional multimedia is becoming common on the Web and in educational settings. From Flash to streaming video to voice over IP, the proliferation of multimedia technologies will continue as the classroom and schools become more technologically advanced. However, accessibility of Web multimedia to persons with disabilities is a major hurdle to those who understand the ethical implications of Web accessibility and to those seeking legal compliance. Captions provide a way for the deaf, hard of hearing, and learning or language impaired to access and better understand multimedia content. Cost-effecting and easy-to-use tools for on-demand and real-time captioning will be presented.
Introduction
Captions are text versions of the spoken word. Captions allow Web audio and video to be both perceivable to those who do not have access to audio and understandable to a wider audience. Though captioning is primarily intended for those who cannot receive the benefit of audio, it has been found to greatly help those who can hear the audio, those who may not be fluent in the language in which the audio is presented, or those who may have learning/cognitive impairments.
The Web Content Accessibility Guidelines 1.0 of the World Wide Web Consortium, which are the de facto international standard, indicate that you should, "provide equivalent alternatives to auditory and visual content". Section 508 of the Rehabilitative Act states that, "Equivalent alternatives for any multimedia presentation shall be synchronized with the presentation." According to these guidelines captions should be:
• Synchronized - the text content should appear at approximately the same time that audio would be available
• Equivalent - content provided in captions should be the same as that of the spoken word
• Accessible - caption content should be readily accessible and available to those who need it
On the Web, synchronized, equivalent captions should be provided any time audio content is presented. This pertains to the use of audio and video that is played through multimedia players such as Quicktime, RealPlayer, or Windows Media Player, but can also pertain to such technologies as Flash, Shockwave, or Java when audio content is a part of the multimedia presentation. There are many technologies that allow for the captioning of archived, stand-alone video on the Web. With real-time delivery of audio and video content over the Web, captioning is much more problematic.
The Process & Tools
There are two primary forms of Web multimedia - on-demand and live. With on-demand or archived audio/video resources, captioning is almost always easily accomplished. The process of captioning on-demand multimedia typically involves the following steps:
1. Acquire a text version of any 'relevant' spoken content 2. Convert the text into a form understood by the media technology and generate synchronization information.
3. The media and the captions must be presented to the user.
With live or real-time multimedia, each of these three steps must be completed in real-time. The acquiring of a text version of the audio content is usually done by a stenographer. A stenographer can 'type' what is being spoken with minimal delays and with high accuracy. There are a variety of stenography technologies and applications that can be used. Voice recognition technologies provide another potential method for converting audio into text in real time.
As the text version of the audio is being created, it must be converted into a format that can be broadcast to the end user. A few Web multimedia applications allow the text captions to be transported with or embedded into the audio/video broadcast. In most cases, the text information must be transmitted using another technology. In other words, the end user may view choose to view a video using a common media player, but if that player does not support real-time captions, then another application must be open to display the captions.
Finally, the captions must be presented to the end user in an accessible manner. The text must be timely (i.e., roughly synchronized with the audio of the broadcast) and the user must be able to adequately view them.
WebAIM's Solution
WebAIM is developing a real-time, Web-based captioning program that easily and cost effectively allows live audio and video broadcasts on the Web to be fully accessible to people who are deaf or hard of hearing. WebAIM captioning application allows for stenographer input from a variety of current steno applications. This stenographer data is then converted into manageable portions and packaged in a format for broadcast across the Web. The end users simply open a client application to receive the captions. WebAIM is exploring the capabilities of broadcasting this text to a number of client applications, including the major media player (Microsoft Windows Media Player, Real Network's RealPlayer, Apple's Quicktime, and Macromedia Flash), instant messaging programs (Windows Messenger, ICQ, etc.), browser based Java applets, and is even pursuing accessibility to wireless devices, such as cell phones and PDAs. The text information may even be formatted in a way so that refreshable B! raille devices may for the first time have access to live Web-based broadcasts in real time.
Such technologies are not limited to natively Web-based applications. Real-time captioning applications allow the broadcast of text to any one that has an Internet connection. As such, traditional television, satellite, radio, and other broadcast mediums can provide an accessible alternative via Web-based broadcasting of real-time text.
WebAIM will discuss the difficulties and barriers to making live Web broadcasts accessible to the deaf and hard of hearing. We will also overview existing standards and technologies for real-time captioning, as well as showcase their own real-time captioning application.
Resources
Fortunately, there are many online resources available to help developers gain an understanding of the technologies and standards used for Web captioning. WebAIM has developed extensive tutorials at http://www.webaim.org/techniques/captions/. Developers of the media players also have extensive, though somewhat complicated, resources on how to develop captions for their respective players. See 'Relevant Resources' below.
Relevant Resources
• Flash - http://www.flash.com/
• Hi-Caption - http://www.hisoftware.com/hmcc/index.html
• MAGpie - http://ncam.wgbh.org/webaccess/magpie/
• Quicktime - http://www.quicktime.com/
• Quicktime Text Track - http://www.apple.com/quicktime/tools_tips/tutorials/ textdescriptors.html
• RealPlayer - http://www.real.com/
• RealText - http://service.real.com/help/library/guides/realtext/realtext.htm
• SAMI - http://www.msdn.microsoft.com/library/en-us/dnacc/html/ atg_samiarticle.asp
• SMIL - http://www.w3.org/AudioVideo/
• Timed Text - http://www.w3.org/AudioVideo/TT/
• WebAIM - http://www.webaim.org/
• Windows Media Player - http://www.windowsmedia.com/
Acknowledgements
Web Accessibility In Mind (http://WebAIM.org) is administered in K-12 settings through a grant provided by the Office of Special Education Programs (OSEP) of the Office of Special Education and Rehabilitative Services (OSERS). Funding for our captioning products is funded by the National Center on Disability and Access to Education (http://ncdae.org).
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