IT Accessibility News – April 2011

Table of Contents

Thinking about Audio Descriptions in Videos

While we are all pretty familiar with alternative text for images, there is also a corresponding equivalency for videos called an “audio description”. Whereas in images the alternative text provides a textual description of the image, in videos the audio description provides details of important events occurring in the video. The audio descriptions are actual audio snippets inserted into the video to provide information about events that are happening in the video that aren’t available to the user in a non-visual way.

Audio descriptions are part of the new WCAG 2 standard (Section 1.2.5). Section 508 and the Americans with Disabilities Act are currently being updated and amended, and it is looking increasingly like they will require conformance to WCAG 2 Level AA. As we move forward it is important to start thinking about these issues as we produce more and more video online.

Here is an example of audio descriptions in action in a preview of an animated version of Hamlet. Here is an example of a television program with audio descriptions. Notice how there are actual descriptions of the scene along with the regular dialogue. You can also read a more in-depth description of audio descriptions in this blog posting.

Since this topic will be new to many people I will be providing some additional resources for it on a future date.

Accessible Video Players

One of the problems with videos that are embedded in a Web page is that the actual controls to navigate the video (play, pause, fast forward, etc.) are not accessible. Either they require a mouse to use them or they don’t work well with screen readers. HTML5 provides some great possibilities for accessible video players for the future, but as the HTML5 spec is still being worked out if you need an accessible video player, I recommend looking at the JW Player from LongTail Video. It is quite accessible and very flexible.


If you need to put math on a Web page, MathJax is something you need to check out. MathJax is a JavaScript library that allows you to write math equations in TeX, LaTeX, or MathML and have the equations rendered directly in the browser without having to create separate image files. Since the equations are already written in a standard language like TeX or MathML, it is much easier for assistive technologies to interact with the equations.


AccessibleU is a site that demonstrates several common accessibility issues with Web pages and how to correct them. I will continue to develop the site to include more accessibility issues and demonstrate more techniques. This site is based on work previously developed at the University of Washington.

Speech Recognition within the Browser

You have probably seen and/or experimented with Web-based or mobile-based speech recognition applications. They all have varying degrees of accuracy and hilarity (the two are inversely proportional). There is a proposed W3C Speech API to enable speech recognition directly in the browser. Who knows where this will actually lead, but Google has already implemented it in Chrome, and you can try it out for yourself.

To test it out, it’s not as simple as pointing and clicking.  You will have to start Chrome using the enable-speech-input flag. On my Windows 7 computer, from the command line I ran

C:\Users\gdkraus\AppData\Local\Google\Chrome\Application\chrome.exe --enable-speech-input

After starting Chrome in this way you can follow the previous link and click on “this little demo” or go to the page directly. (Thanks to Hal for pointing out this resource!)