Captioning Access on the Internet

Captioning Access on the Internet

October 2003

Editor: This workshop was presented at the 2003 TDI convention by Linda Idoni, who is the director of the West Coast office of Media Access Group (MAG) at WGBH. Their website is


Linda reported that about 80% of the work her office does is for broadcasting. They also do some DVD captioning, and expect that work to increase. They currently do very little web captioning.

She pointed out that an estimated 36 million people have some form of sensory loss, and 24 million of them have hearing loss. Text based information is great for both groups (with screen readers for those with vision loss); but now that we are getting more video on the Internet, we need to make sure it’s accessible. Adding captions, descriptions, and subtitles will ensure access.

People with vision loss access Internet information using screen readers, which are programs that convert text to audible speech. Access is provided to those with vision loss by ensuring that all images have alternative text descriptions, which the screen readers can use.

WGBH has developed a program called MAGpie, which allows authors to add captions, subtitles, and description to the four popular video formats. It is available for PC and Mac. You can learn more about MAGpie and download it free at

Source code, examples, etc. are available at That site also has information on general conventions and design guidelines, including Math and Science Solutions; it’s really a wonderful guide to Internet captioning.

MAG continues to develop tools for web-based applications, CDs, etc. They support Windows Media, QuickTime, Real Media, and Flash.

Rich media is defined as elements on a web page or in a separate player that exhibit dynamic motion or responses to user interaction. Examples include streaming video, animated interactive tools, animated Flash, and image slideshows.

MAG is a non-profit organization. It established the Caption Center in 1972, the world’s first descriptive video service in 1990, and NCAM in 1993. NCAM is a research, development, and advocacy entity.

On TV, captions are hidden and must be selected. On the web, captions are in a separate file and can be selected or not.

When you create captions and descriptions with MAGpie, you create a captions track and an audio description track. MAGpie assigns time codes to each caption or description component to ensure that these tracks are synched with the video.

MAG also produces Arthur, an accessible TV program for kids.

They have developed a new software tool called closed captioning Internet Real Time (ccIRT), which extracts television captions from line 21 so they can be used to create Windows Media or Real Player captioning. ccIRT is not yet publicly available.

Rich Media Resource Center contains examples of accessible rich media, various tools, tutorials on captioning and audio descriptions, and current news.

We encourage everyone to be a Web Access Advocate. Each of you can alert webmasters of the need for captions and description, and tell them where to get the tools.

Q: Do any of existing Internet videos have captions already on them?
A: Not many – our stuff is captioned, but a lot of stuff isn’t. There are some deadlines in effect, but they are sliding. IBM, Microsoft, and some others do a pretty good job of captioning their videos.

Note that in all the multimedia players, the user must turn captioning on; this is usually done in the “Preferences” menu.

Q: What is the difference between MAGpie and ccIRT?
A: You use MAGpie to actually create captions. ccIRT takes the television captions and creates a captioning file for the streaming version on the internet.

You must download MAGpie to be able to see captions in Flash. For the other multimedia formats, you don’t need MAGpie unless you want to create captions.