IETF
The "Internet Engineering Task Force" (commonly known as the "IETF") is responsible for documenting many defacto standards. They produce many specifications as a part of doing that. See also: Category:Documentation.
RTSP
- main article: RTSP
User:RobLa made a point to going to IETF meetings between 1996 and 2002 because he was working on RTSP. RTSP was published as RFC 2326 (and updated as RFC 7826). Apple still seems to support RTSP in Quicktime. RealNetworks was originally known as the publishers of RTSP-based servers and clients, btu it's been a while.