Like H.323, RTSP uses RTP (Real-Time Transport Protocol) to format packets of multimedia content. But whereas H.323 is designed for videoconferencing of moderately-sized groups, RTSP is designed to efficiently broadcast audio-visual data to large groups.

RTSP grew out of work done by Columbia University, Netscape and RealNetworks.

RTSP FAQ from RealNetworks
Contains a list of frequently asked questions about the Real Time Streaming Protocol (RTSP).

RTSP Information page
Includes links to draft documents, as well as other information about RTSP, RTP and other protocols that fit into the Internet Multimedia Conferencing Architecture (IMCA). This page is hosted by Dr. Henning Schulzrinne, co-author on RTSP as well as RTP.

RFC 1889
Request for Comments document for the Real-time Transport Protocol (RTP).

RFC 2326
Request for Comments document for the Real Time Streaming Protocol (RTSP).