A

AGC

See 'auto gain control'...

auto gain control

Auto gain control (AGC) is a feature that allows the camera to automatically adjust the overall gain of an image to help normalize the output levels. As the lighting changes, the camera will attempt to keep the overall image at a consistent level of brightness.

auto iris

In an auto iris configuration, the camera maintains a fixed shutter speed and varies the size of the lens aperture in accordance with lighting conditions. See also 'manual iris'.

auto white balance

Auto white balance (AWB) is a feature in cameras that is used for color correction. Shifting lighting conditions can sometimes cause improper video coloration, and AWB attempts to correct this.

AWB

See 'auto white balance'...

B

backlight compensation

Backlight compensation (BLC) is a feature in cameras used for scenes with too much light behind a subject, which can cause silhouetting. BLC will automatically adjust the contrast to help bring out the detail that was lost.

BLC

See 'backlight compensation'...

H

H.264

H.264 is the most recent addition to the MPEG4 family of audio/video formats. It supercedes MPEG4 part 2 which is commonly used in DVRs, and offers significantly greater compression than JPEG2000 and MPEG4 part 2 with only slight degradation of quality. See also 'MPEG4' and 'JPEG2000'.

J

JPEG2000

JPEG2000 is an audio/video format developed by the Joint Photographic Experts Group. As it relates to DVRs, it is one of the major compression algorithms used, and offers a higher image quality than most other formats, but at the expense of bandwidth/recording space. See also 'H.264' and 'MPEG4'.

L

looping video

Looping video is a feature on DVRs and monitors that simply means that the video input also has a pass-through video output. On monitors it is used to chain multiple monitors together. On DVRs it allows you to hookup individual spot monitors for each camera.

lux

Lux is the SI unit of illuminance, and in cameras is used to measure the minimum lighting required for the camera to register a usable image. A well-lit office area is about 400 lux.

M

manual iris

In a manual iris configuration, the lens aperture is fixed and the camera adjusts its shutter speed in accordance with lighting conditions. See also 'auto iris'.

MPEG4

MPEG4 is a widely used audio/video format created by the Moving Pictures Experts Group. As it relates to DVRs, it is one of the major encoding algorithms used, and offers greater compression and lower bandwidth requirements than JPEG2000, at a slight loss of visual quality. Typically DVRs labeled as MPEG4 utilize MPEG4 part 2, which is not to be confused by MPEG4 part 10 (H.264). See also 'H.264' and 'JPEG2000'.

P

PTZ

PTZ is an acronym for Pan, Tilt & Zoom.

R

RS-485

RS-485 is a 2 or 4 wire interface that is common among devices that support pan/tilt features. Most DVRs have support for controlling RS-485-enabled cameras and pedestals.

T

TVL

TVL is an acronym for TeleVision Lines, and is a measurement of resolution for composite video. It is not to be confused with the pixel resolution used to describe digital images. An average CCTV camera has about 420 TVL, while a high resolution camera would be 480 TVL or higher.

twisted pair

See 'UTP'...

U

UTP

Unsheiled Twisted Pair (UTP) is a type of cable primarily used in networking. It can also be used to send composite video over much longer distances than RG59/RG6 cable.