Today most of the browsers use a flash plugin to play the videos.This works pretty well but Flash unfortunately requires a lot of computing power.This would be an issue if the system has a low end configuration Hence the new web standard HTML5 is trying to change that.
For example, with WAI-ARIA, developers can identify regions of pages and enable keyboard users to easily move among regions, rather than having to press Tab many times.
It is primarily for developers of Web browsers, assistive technologies, and other user agents; developers of Web technologies (technical specifications); and developers of accessibility evaluation tools.
WAI-ARIA, the Accessible Rich Internet Applications Suite, defines a way to make Web content and Web applications more accessible to people with disabilities.