RTP

The RTP (Real-Time Transport Protocol) is a protocol for 'unreliable' delivery of Real Time data layered on top of UDP. Used a lot for streaming of audio and video it is often controlled by an RTSP session.

Due to UDP it is able to use multicast. It is closely tied to the RTCP protocol.

VLC has built-in support for RTP as a server (streaming output). As a client, VLC uses the LiveMedia library.