In doing some more internal research here at PB Web Development on accessibility and videos I've come across this video presentation by Silvia Pfeiffer at a Google Developer's conference in March 2011.
I've seem a similar presentation by Silvia late in 2011 at the OZeWAI conference where she presented the same if not similar content. We'll worth watching if you're involved in accessibility and videos.
It is exciting to see some new technologies emerging and things slowly being taken up.
Link directly to YouTube video of the presentation.