Some Basics on Video Surveillance Recording Systems


Choosing the right cameras is only a small part of putting your surveillance system together. At least as important, in the long term, is deciding how you’ll record and store your video. The best solution will depend on your needs and how you anticipate them changing. While large deployments at government institutions or campuses will usually depend on server-based solutions, we’ll be focusing on household and small business needs.

Long gone are the days when surveillance video was recorded to a video cassette. A surveillance DVR (Digital Video Recorder) is pretty much the same thing as the average device from your cable company. It just has a bunch of extra functions, and records from cameras instead of your cable. It can be connected to the Internet so you can review video remotely. OK. Maybe they’re completely different things, but they both record video.

FLIR M3100E Series 16-Channel 1080p HD-CVI DVR with 2TB HDD
FLIR M3100E Series 16-Channel 1080p DVR

A DVR and an NVR (Network Video Recorder) are similar products used with different types of cameras. Analog cameras with BNC outputs will connect to a DVR, which converts and stores video in digital format, and IP cameras will connect to an NVR, usually. Hybrids are a thing, and they straddle the line between the different devices as far as inputs, but usually (usually) perform as DVRs.

Hikvision Pro Series 16-Channel 12MP NVR

The Absolute Basics

The primary function of both recording devices is the recording of video for storage and review; just like it says on the tin. They both record to hard drives. DVRs and NVRs are both classified by the number of video channels they can record simultaneously (4-channel, 8-channel, 16-channel, etc.). They store data to hard drives, just like a computer. While many have additional inputs for things like microphones or alarm sensors, it’s the number of cameras they can support that defines them. Many also act as controllers for PTZ (Pan/Tilt/Zoom) camera functions.

What to Look for And What It Means

A DVR, as mentioned above, records from analog cameras. It’s essential for anyone who wants to do more than live monitoring, and is generally the best way to set up multi-camera views. A DVR will be the center of your video surveillance system, so you’ll want to pay attention to a device’s features before purchasing.

Look at hard-drive compatibility. Most devices include storage, but you may want to replace what yours comes with. If you do, make your decision carefully. A surveillance recorder should be able to run for long periods without rebooting. Higher-end DVRs will use surveillance hard drives designed for near-24/7/365 up times.

Every system has a maximum number of video channels it can support, as well as a maximum total video resolution and frame rate. Resolution and frame rate will generally be split across available channels; an 8-channel DVR can record 8 channels of video in 720p resolution each at 15 fps, or 4 channels at 1080p 30 fps, for example.

One of the advantages that network cameras have over analog cameras is their ability to perform scene analysis and store data themselves. Connected DVRs perform almost all those functions for most cameras, while NVRs will act as backups and add-on functions. Recording can be triggered by motion in a scene, the tripping of external sensors, setting schedules.

What you can do with recorded video varies, too. There are several common analytics functions found in many DVRs and NVRs. These are just a few:

  • Line Crossing Detection: Highlights points in a video where someone or something crossed a virtual line you drew across a scene
  • Entrance/Exit Detection: Highlights points in a video where someone entered or exited the camera’s view
  • Scene Change Detection: Highlights points in a video where there was a drastic change in the camera’s field of view, usually indicative of a camera having been moved
  • People Counting: Indicates how many individuals entered the monitored area in a specific segment of video
  • Heat Mapping: Highlights areas in a scene where the most activity occurred.

Video will almost always be able to communicate over Ethernet for live monitoring, playback, and making updates to settings, and have an HDMI and/or traditional video output for local use.

Video Streaming

Capabilities and quality can vary based on whether a recorder is accessed locally or over the Internet. Most will display at a lower resolution when connected remotely. Check to see if separate resolutions and frame rates are listed in a device’s specs, to know for sure. Many devices even have companion apps that allow users to view surveillance video and make some changes to settings from anywhere they have Internet access.

Some manufacturers also offer automated web backup and cloud storage of your footage, for an additional fee, giving you an additional layer of protection and peace of mind.

Everyone’s needs are different. Whatever yours are, we can help you to meet, and maybe even beat, them. Contact our product specialists and we’ll help you put together the system that’ll work best for you. For more information, stop by the B&H SuperStore in New York, speak with a sales professional on the telephone at 1-800-606-6969 or contact us online via Live Chat.