Welcome to the Video Surveillance Glossary, your reference guide for key terms, definitions, and concepts used in modern security systems.
If you’re expanding your knowledge, explore our Access Control Glossary and Fire Alarm Glossary for more related terminology. These resources are designed to help security professionals, integrators, and end users better understand the technologies shaping today’s security solutions.
Video Surveillance Glossary
A complete A–Z reference of key video surveillance terms for security professionals and integrators.
Video Surveillance Glossary Terms and Definitions
A
AEC/ANR/AGC
Audio echo/noise/gain controls improving clarity.AHD
Analog High Definition is both a general term and the name of a specific variant/implementation of megapixel analog, in contrast to the more widely used megapixel IP.Analog Camera
Legacy camera outputting composite analog video (CVBS) over coaxial cable.ANPR
Automatic Number Plate Recognition, also called LPR (License Plate Recognition), in some parts of the world, is software that analyzes and detects the characters on plates. Typically specialized…AoV
Angle of View describes the camera's coverage area in degrees. It is often used interchangeably with field of view (FoV).Aperture (F-Number)
Lens opening; lower F-number passes more light.API
Application Programming Interface is a means whereby systems (e.g., IP cameras or recorders) allow 3rd party systems to integrate.ASIS
Originally stood for the American Society for Industrial Security, now called ASIS International, an association focused on security end-users.Aspect Ratio
The ratio of image height to width. In surveillance, 16:9 is the most common aspect ratio.Audio In/Out
Microphone/line interfaces for recording or talk-down.AWG
American Wire Gauge is a standard scale of wire gauge used predominantly in North America.
B
Bandwidth Planning
Sizing links for peak aggregate bitrates and overhead.Bitrate
Amount of data per second; determines quality and bandwidth/storage usage.BLC/HLC
Back Light Compensation is a digital image adjustment which adjusts exposure to attempt to improve details on subjects in front of strong backlight. HLC is Head Light CompensationBullet/Dome/Turret
Common fixed-camera form factors for indoor/outdoor installs.
C
CBR
Constant Bit Rate is a camera streaming mode that aims for a constant bandwidth level while video quality is allowed to vary.CBR/VBR
Constant vs Variable bitrate control modes for encoding.CCD
Charge Coupled Device, a type of image sensor which reads pixels of an image one by one.CCP / CPC
China Communist Party or Communist Party of China.CMOS
Complimentary Metal Oxide Semiconductor. In surveillance, a CMOS sensor reads pixels of an image all at once.CMOS/CCD
Image sensor technologies; CMOS is dominant today.CNN
Convolutional Neural Network. Used in deep learning to classify images, perform object recognition, and detect image similarity.Coax/IP Media Converter
Translates coax to Ethernet/PoE for retrofits.Colorâ at Night / Starlight
Low-light color imaging via large sensors/fast lenses/AI denoise.Crowd/Occupancy
Estimates crowd density and occupancy levels.Cyber Hardening
Disable unused services, rotate creds, HTTPS, certificates.Cyber Video Export Policy
Rules defining who can export, how long, and where.
D
dB
Decibels are a measurement of the difference in two power levels, most commonly used to specify WDR in surveillance.Deep Learning
An algorithm which goes through hierarchical classification stages to reach decisions, such as human, vehicle, animal classification.Depth of Field
Range of acceptable focus; wider with small apertures and short focal lengths.DHCP
Dynamic Host Configuration Protocol assigns an IP address to devices on a network within a specified range.DNR
Digital Noise Reduction uses software to attempt to reduce image noise present in low light surveillance images.DVR (Digital Video Recorder)
Digital Video Recorder receives video from connected analog sources, encodes it, and stores it to disk.DWDR
Digital Wide Dynamic Range is a contrast adjustment on multiple regions of the scene, not as effective as true WDR.
E
Edge AI
Running analytics on-camera or at gateway for low latency.Edge Storage (SD)
Recording to microSD inside camera for redundancy or stand-alone.EIS
Electronic Image Stabilization minimizes blurring and compensates for device vibration.EOL
End-Of-Life describes products which have been discontinued by the manufacturer.Event-Based Recording
Record on motion, analytics, input triggers instead of 24/7.Export/Clip Locker
Chain-of-custody export with player, hash and audit trail.
F
F/F-Stop
F-stop measures the relative amount of light that a lens passes, expressed on a logarithmic scale.Face Detection/Match
Locates faces and compares to watchlists with consent/policy.Failover Recording
Automatic recording takeover by standby servers/storage.Federation
Multiple sites/servers managed under one logical VMS.Firmware Management
Planned upgrades with rollback/validation windows.Fisheye / 360¡
Ultra-wide lens producing hemispheric images; dewarped in VMS.Fixed Lens
Fixed lenses are locked into one focal length, e.g., 2.8mm, 4mm, etc.FoV
Field of View, refers to what a camera can see.FPS
Frames Per Second, the number of images a camera captures and/or transmits in one second.Frame Rate (FPS)
Number of frames captured per second; affects smoothness and storage.Frame Types
I-frames, P-frames, and B-frames are different types of frames used in encoding surveillance video.
G
GDPR
European Union's General Data Protection Regulation, covering restrictions on personal information usage.GOP
Group Of Pictures, a collection of frames beginning with an I-frame including subsequent P and B frames.GPU
Graphics Processing Unit, useful for server-side video surveillance analytics.GPU Acceleration
Using GPUs for real-time analytics/transcoding.
H
H.264/AVC
Widely used video codec; good balance of efficiency and compatibility.H.265/HEVC
Newer codec with ~40-50% savings vs H.264 at similar quality; more processing requiredHD-Analog (TVI/CVI/AHD/HDOC)
High-definition analog formats carrying 720p/1080p/4K over coax.HD-CVI
High Definition Composite Video Interface, an HD analog standard developed by Dahua.HD-TVI
High Definition Transport Video Interface, an HD analog standard developed by Techpoint and adopted by Hikvision.HDD
Hard Disk Drive, the most commonly used storage medium in surveillance.Health Monitoring
Proactive checks of disks, camera uptime, stream quality.HFoV
Horizontal Field of View, the angular width of a camera field of view in degrees.HLC
High Light Compensation reduces effects of strong light sources like headlights.Hot Spare
Idle drive that auto-rebuilds a failed RAID member.HTTP(S) Tunneling
Delivering video over HTTP/HTTPS to traverse firewalls and proxies.
I
IK
IK ratings are measurements of impact resistance defined in EN 62262, ranging from IK00 to IK10.Ingress Rating (IP66/IP67)
Dust/water resistance rating of outdoor devices.IP
Ingress Protection ratings dictate how hardened a device is against dust, water, and debris.IP Camera
Digital camera that transmits video over an IP network using standard protocols.IPC
Internet Protocol Camera, a digital surveillance camera that transmits information over a network.IR
Infrared, light above the visible spectrum, used in illuminators to provide light cameras can see but humans cannot.IR Cut Filter
Mechanical filter that moves for true day/night color fidelity.IR Illumination
Infrared light for night vision; integrated LEDs or external illuminators.
L
LAN
Local Area Network, a collection of devices connected together in one physical location.Lens Focal Length
Determines angle of view; shorter=wide, longer=telephoto.Loitering/Intrusion
Rules triggering alarms on behaviors in zones/lines.LPR
License Plate Recognition, also called ANPR, software that detects and analyzes plate characters.LPR/ANPR
Automatic plate capture/recognition with search/alerts.Lux
Illuminance measure; lower minimum lux indicates better low‑light ability.
M
MAC Address
Media Access Control address, a unique identifier assigned to a Network Interface Card.Machine Learning
Uses pre-programmed instructions to allow a computer to recognize images of objects.Maps/Floorplans
Graphical view to click cameras, doors, alarms by location.MBR
Maximum Bit Rate, a streaming mode allowing bitrate to vary up to a maximum while maintaining quality.MJPEG
Stream of individual JPEG frames; high quality, high bandwidth.Motorized Varifocal
Remote-adjustable focal length and focus from VMS/NVR.MP
Megapixel, refers to camera resolution such as 1080p/2MP, 4MP, etc.MSRP
Manufacturer Suggest Retail Price, also called list price.MTF
Modulation transfer function; lens contrast/detail performance metric.Multi-Sensor Camera
Several sensors/lenses in one housing for wide coverage.
N
NAS
Network Attached Storage, a small device used to store video on the network.NAS/iSCSI
Network storage targets used by NVR/VMS for recording.NDAA
National Defense Authorization Act of 2018 banning certain manufacturers in surveillance.NEMA
National Electrical Manufacturer Association, often refers to weather ratings of enclosures.NIC
Network Interface Card, a component that allows a device to connect to a network.NTP
Network Time Protocol synchronizes time of devices to a reference source.NVR (Network Video Recorder)
Recorder that ingests IP streams and stores digital video.
O
Object Left/Removed
Detects abandoned or removed items.ONVIF
Open Network Video Interface Forum, trade group with specifications for Interoperability standards for IP video devices and VMS integrations
P
People/Vehicle Counting
Counts objects entering/leaving zones for KPIs and planning.PoE
Power Over Ethernet, standard for supplying low voltage power over Ethernet cable.PoE/PoE+/4PPoE
Power standards 802.3af/at/bt powering cameras over Ethernet.PPF
Pixel Per Foot, a metric of image quality based on pixel resolution and field of view width.PPF/PPM
Pixels per foot/meter; used to design identification/recognition views.Pre/Post-Alarm Buffer
Frames stored before/after trigger to give full context.Privacy Masking
Blocks areas of the image to protect privacy or compliance.PSIM
Physical Security Information Management, integrates multiple systems into a single monitoring app.PTRZ
Pan/Tilt/Roll/Zoom cameras, similar to PTZ but adds roll adjustment for installation purposes.PTZ
Pan/Tilt/Zoom cameras with motorized movement and zoom capability.PTZ (Pan/Tilt/Zoom)
Remotely moves and optically zooms for active surveillance.
R
Radiometric Thermal
Thermal camera that outputs calibrated temperature values.RAID
Redundant Array of Inexpensive Disks, connects multiple storage devices into one space with redundancy.RAID 0/1/5/6/10
Disk topologies balancing performance, capacity and redundancy.Resolution
Pixel dimensions of the image (e.g., 1920×1080).Retention Policy
Days of video kept before overwrite; may vary by camera.RFP
Request For Proposal, outlines requirements for a project.RMA
Return Merchandise Authorization, process of returning a product for refund, replacement, or repair.Rolling vs Global Shutter
Readout modes affecting motion artifacts and distortion.RTP/RTCP
Transport protocols carrying audio/video streams and control/quality metrics.RTSP
Real Time Streaming Protocol, used by cameras as a link between camera and viewers/VMS software.
S
SAN
Storage Area Network, larger than NAS, used for higher performance storage.Sensor Size
Physical size of image sensor; larger sensors improve low-light.SIA
Security Industry Association, US-based trade organization representing manufacturers.SLA / Uptime
Service-level objectives for availability and response.Smart Codec
Scene-adaptive encoding that lowers bitrate in static regions of the imager.Smart IR
Features that adjust IR illumination to compensate for moving objects or scene changes.Smart Search
Rapid post-event search by motion, region, object class, color, path.SNMP
Simple Network Management Protocol, used for monitoring devices over a network.SoC
System on a chip, computing component of IoT devices like IP cameras and recorders.Static IP
Static IP addresses are manually assigned and do not change, recommended for surveillance devices.Surge/Lightning Protection
SPD and bonding practices for outdoor cameras.SVC (Scalable Video Coding)
Encoding technique allowing resolution/frame‑rate layers.
T
Tamper Detection
Detects defocus, obstruction, movement, spray paint.Temperature Screening
Measuring apparent skin temperature with controlled workflows.Text/Metadata Overlay
Adding time, camera name, logos, or analytics data to video.Thermal Camera
Thermal surveillance cameras use infrared radiation to produce images without visible light.Time Sync (NTP)
Keeps timestamps consistent across cameras/servers.
U
UPS
Uninterruptible Power Supply, a battery backup system maintaining power during outages.
V
Vandal Rating (IK10)
Impact resistance rating for domes/housings.Varifocal Lens
Varifocal lenses allow adjustment of focal length, providing flexible fields of view.VBR
Variable Bit Rate, streaming mode allowing bitrate to vary while maintaining constant quality.VCA
Video Content Analysis, analytics rules like intrusion detection, people detection, LPR, etc.Video Verification
When an intrusion alarm is triggered, monitoring reviews live video or a clip to confirm.Video Wall
Multi-display operator surface for situational awareness.VMD
Video Motion Detection, detects motion based on pixel changes, less accurate than analytics.VMS
Video Management Software, software installed on COTS hardware for managing surveillance video.VMS (Video Management System)
Software platform for live view, recording, search, export, alarms and analytics.VOIP
Voice over Internet Protocol, transmitting voice over a network or internet.VSaaS
Video Surveillance as a Service, cloud-based surveillance models.
W
Watermarking
Cryptographic stamp proving recording authenticity/integrity.WDR (Wide Dynamic Range)
Combines exposures to handle bright/dark areas in one scene.
Z
Zoom Ratio
Ratio of a camera's maximum focal length to its minimum, e.g., 30X.
#
3D DNR
Digital noise reduction to clean low-light grain and reduce bitrate.
This Video Surveillance Glossary is part of our ongoing effort to provide educational resources for the security industry. For deeper insights, check out our related blog posts such as Video Surveillance Best Practices or Electronic Access Control Basics. If you have questions or want to explore product options, contact our team for expert support.