This document aggregates the accessibility requirements of users with disabilities that the W3C HTML5 Accessibility Task Force has collected with respect to audio and video on the Web.It first provides an introduction to the needs of users with disabilties in relation to audio and video.Then it explains what alternative content technologies have been developed to help such users gain access to the content of audio and video.A third section explains how these content technologies fit in the larger picture of accessibility, both technically within a Web user agent and from a production process point of view.This document is most explicitly not a collection of baseline user agent or authoring tool requirements. It is important to recognize that not all user agents (nor all authoring tools) will support all the features discussed in this document. Rather, this document attempts to supply a comprehensive collection of user requirements needed to support media accessibility in the context of HTML5. As such, it should be expected that this document will continue to develop for some time.
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