One of my developers picked this up at WWW2010 yesterday in the Media on the Web Developer’s Track session. Amazing what modern browsers can pull off:
http://craftymind.com/factory/html5video/CanvasVideo.html
This makes me really eager to see some standardization on video codecs and streaming protocols. Note to google: please open VP8 and back it up with your muscle to give the world a true open video standard! If you can wire a town for gigabit fiber, surely you can foster the adoption of an open video standard.