This document describes a scheme to packetize an H.263 video stream for transport using the Real-time Transport Protocol (RTP) with any of the underlying protocols that carry RTP. The document also describes the syntax and semantics of the Session Description Protocol (SDP) parameters needed to support the H.263 video codec. The document obsoletes RFC 2429 and updates the H263-1998 and H263-2000 media type in RFC 3555.