Standards for Video Accessibility

Session Type: Working group
Session Category: Open Media Developers
Session Leader: Silvia Pfeiffer (Google), Philip Jagenstedt (Opera)

Day: Saturday
Time: 4:00pm – 5:30pm
Faculty Commons

Session Notes


Video and audio have become native Web citizens through their inclusion into HTML5 and implementation in modern Web browsers. Media accessibility approaches have been specified in HTML5, but not yet been included into any released browser. This includes subtitles and captions as much as audio descriptions and sign language video tracks.

In this session we will discuss the new WebVTT file format which provides timed text for video and audio elements. We will discuss limitations that implementers have come across and new challenges that haven’t yet been resolved.

HTML5 video accessibility also has implications on accessibility features of desktop video applications. So, another focus of the session will be to analyze requirements and limitations that desktop (and more generally non-web) applications face in the new HTML5 video environment. One issue to consider in this context will be the authoring of WebVTT files.

We will also discuss the HTML5 multitrack specification which will allow publication of audio descriptions and sign language video in sync with a main video and determine obstacles for its implementation.

Another topic of interest could be about whether it makes sense to add WebVTT as an in-band track to the open WebM and Ogg file formats.

Finally we will discuss other requirements that users of open video have for video accessibility and see if technical solutions can be found.


This session will make progress on the technical realization of video accessibility on the Web.

One possible outcome could be the registration of new bugs on the HTML5 specification, and of bugs on browsers.

Another possible outcome could be the creation of a list of further requirements for video accessibility and video accessibility applications.

Other documents of recommendation or best practices could also result from this session.