Is there an official standard for streaming HTTP?
IIS Smooth Streaming refers to a technical overview document here:
http://learn.iis.net/page.aspx/626/smooth-streaming-technical-overview/
Apple has an offer for HTTP Live Streaming here:
http://tools.ietf.org/html/draft-pantos-http-live-streaming-01
but I could not find the official standard for HTTP streaming.
EDIT / Answer
Thanks to Remy for his correct answer.
The more I looked at it, the more I realized that all this is very spoiled. Several companies support HTTP Streaming, but are completely unrelated to each other. The basic concept is the same, they all use a segment to split the video (either in advance or on the fly), a server with a header with information about the parameters and segments of the bitrate, and then serve individual segments upon request.
However, Microsoft, Apple and Adobe each have a completely different way of making these parts that are completely incompatible. The only good thing is that the implementation of Microsoft HTTP Smooth Streaming supports both its own standard and Apple. However, Apple only supports this in QuickTime X on OSX, and even then only in Safari or standalone, and not in the QuickTime plugin used by Chrome or Firefox.