Institute for Telecommunication Sciences / Research Topics / Video Quality Research / Guides and Tutorials / Video Resources / Tools for Video Quality in Public Safety / Guide to Defining Video Quality Requirements / Video System Functions / VQiPS Transport
Transport refers to the effects of moving or copying from one location to another. Transport and Network are terms that go hand-in-hand, depending on the IT engineer’s preference. We refer to it here as transport. The transport can be wired (including fiber optics) or wireless, or any combination of these. The distance of the transport can range from a few feet within a building, to the other side of the world, or into outer space. The transport is known to have unpredictable effects on the transmitting of the electrical signal between two or more electronics devices.
While much engineering work has been done on improving wired and wireless transport, the effect of transport on the electrical signal will continue to be an ongoing issue.
The physical mechanism for moving video from one location to another. Networks may be wired or wireless or a combination of both. Features:
Available bandwidth — how much data a network is able to carry affects the speed and size of the video signal that is able to reach the destination.
Network sharing — other users on the network may reduce the available bandwidth.
Loss of data (digital) — When digital information is transmitted; it is broken into short blocks of data called packets. Each packet is sent separately, and the packets are reassembled on the receiving end of the system. For many reasons some packets are lost in transmission, causing a loss of some pieces of the video picture.
Loss of data (analog) — Noise can interfere with an analog signal (e.g., “snow” on analog TV), permanently obscuring portions of the video field.
Delay — if video is being used for real-time decisions, the network can delay the delivery of the video to the decision maker.