OK, Here's an example: http://channel9.msdn.com/Events/PDC/PDC10/FT13 That's the Herb Sutter Lambdas session. I watched it the other day. Both the high quality and medium quality wmv downloads have severe breakup problems throughout. The streaming version produced the same results, and stopped completely about two-thirds through. The download version stopped too, but I was able to get around it by advancing the scrubber to jump over the bad spot. It was hard to listen to, and there are actually short sections of audio that are missing (different in each encoding version).