Here’s a list a accessible HTML5 Media Players—I have not tested them all—and some articles on how to build one yourself. Know any others? Please leave info in a comment.
Existing Players
Nomensa’s media playerFlash, no longer maintained- JW Player by LongTail
Making Video Accessible(no longer available) by LongTailAccessible JW Player Control using Dojo(no longer available) by Ohio State University
WebPlayer from Yahoo and the WebPlayer WordPress plugin(no longer available)The Workshop video player(no longer available)- Acorn Media Player – via @ghindas, author of Opera article below
- MediaElement.js
- Video.js – an open-source HTML5 video player
- Able Player – by Terrill Thompson (GitHub)
- OzPlayer – by AccessibilityOz
- Fluid Project VideoPlayer (archived)
- Accessible HTML5 Video Player – by PayPal
- Accessible and Responsive HTML5 Video Player – (Universal Video Player) by @LauraKalbag code source
- Plyr – by @sam_potts
Do It Yourself
- Accessible HTML5 Audio Player with Yahoo! Media Player Fallback by Terrill Thompson
- Practical Cross-Browser HTML5 Audio and Video by MSDN
- Accessible HTML5 video player by Dev.Opera
More
- HTML5 Video Player Comparison
- Media Player Accessibility Comparisons (Google Doc)
- Embedded YouTube Test by Terrill Thompson
- Media players and accessibility by AccessIQ