The Session Description Protocol (SDP) is a format for describing multimedia communication sessions. It is used to negotiate parameters for audio and video streams in real-time communication applications, such as Voice over IP (VoIP) and video conferencing.
SDP is a text-based protocol that describes the media streams, codecs, and network information needed to establish a communication session between two or more parties. It includes details such as the session name, media types (e.g., audio, video), network addresses, and codec information.
SDP is typically used in conjunction with other protocols, such as the Real-time Transport Protocol (RTP) for transporting media streams, and the Session Initiation Protocol (SIP) for session establishment and control.
Example (SDP Message): An example of an SDP message describing a session with audio and video streams:
v=0
o=- 2890844526 2890844526 IN IP4 192.168.1.1
s=My VoIP Session
c=IN IP4 192.168.1.1
t=0 0
m=audio 49170 RTP/AVP 0
a=rtpmap:0 PCMU/8000
m=video 51372 RTP/AVP 31
a=rtpmap:31 H261/90000