Video Streaming Protocols
Video surveillance systems currently are undergoing a transition where more and more
traditional analog solutions are being replaced by digital solutions. Compared with an analog
video surveillance system, a digital video surveillance offers much better flexibility in video
content processing or data transmission. At the same time, it, also, have ability to implement
advanced features such as motion detection, facial recognition and object tracking.
Applying digital systems, makes the security system capable of transmitting video through
the Internet, so we need to study the different methods of video streaming over the network.
Streaming is the process of playing a file while it is still downloading. Streaming video is a
sequence of "moving images" that are sent in compressed form in a way that it can start being
proceed before it is completely received like video clips on a Web page.
Here, some of the network protocols used in video streaming are described. The focus is on
the features of most important protocols in video surveillance including TCP, UDP and RTSP.
Protocols in streaming technology:
Protocols are the rules implemented for a particular technology, which in streaming technology
are used to carry message packets, and communication takes place only through them. Some of
the protocols used in streaming technology are described as follows:
SDP, standing for Session Description Protocol, used to describe multimedia sessions
in a format understood by the participants over a network. The purpose of SDP is to convey
information about media streams in multimedia sessions to help participants join or gather
information of a particular session.
In fact, SDP conveys information such as session name and purpose, times the session is active,
codec format, media in the session, Information to receive those media (addresses, ports, formats
and so on). A participant checks these information and takes the decision about joining a session.
SDP is aimed primarily for using in large WANs (Wide-Area Network) including the internet. However,
SDP can also be utilized in proprietary LANs (Local Area Networks) and MANs (Metropolitan Area Networks).
Dynamic Host Configuration Protocol (DHCP) is a network protocol that enables a server
to automatically assign a dynamic IP address to each device that connected to the network.
By this assigning, a new device can be added to a network without the bother of manually assigning
it a unique IP address. The introduction of DHCP eased the problems associated with manually
assigning TCP/IP client addresses, resulting in flexibility and ease-of-use to network administrators.
DHCP is not a secure protocol, since no mechanism is built to allow clients and servers to
authenticate each other. Both are vulnerable to deception, as one computer can pretend to be another.