In the ‘platform preview’ of Internet Explorer 10 that is currently available to developers, Microsoft has introduced support for two captioning formats, TTML and WebVTT <track>. This feature adds to the already present support for HTML5 <video> playback which supports both the industry standa4rds H.264 format and the newer WebM format.
As reported in Media Access Australia’s W3C column last year, HTML5 video is a positive step towards accessible media player support that is built into web browsers rather than having to rely on third part plugins such as Adobe Flash Player. The benefits include default video playback controls that are provided by the web browser and accessible using the keyboard as well as a standard captioning format.
The latest implementation of the TTML and WebVTT <track> captioning support means that developers can now show HTML5 <video> captions and subtitles. A demonstration of the latest captioning support in Internet Explorer 10 is available on the Microsoft test drive website.
In the future, developers will be able to use the WebVTT <track> element for audio description, where a screen reader will be able to read out audio descriptions that are time aligned with the video, rather than have to include a separate audio track for audio description which is the common practice now.
The platform preview version of Internet Explorer 10 is currently only compatible with Windows 7 or 8, and only available to download for developers. A number of web browsers already support parts of HTML5, including Mozilla Firefox and Google Chrome. As Internet Explorer remains the most commonly used browser, its move towards improved accessibility is highly promising.
HTML5 is currently under development by the World Wide Web Consortium.
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