Tuesday, January 22, 2013

NVR, DVR, or Video Server?

By Virginia Fair

“Questions………we get questions”

Wasn't that a jingle on a popular TV show of the Sixties? (Seventies?)  Well it could be Kintronics' theme song, too. Our sales engineers get all kinds of questions when fielding calls.

 Today we’ll give you a hypothetical conversation that could occur any day. A caller wants to know what type of video storage device her business should use.

Caller: “What is the difference between a Video Server, a NVR, and a DVR?”
Video Server
Sales Engineer: The network video server is a computer that runs special Video Management Software known as VMS and is used to record video from IP cameras. A windows computer is usually the platform for the VMS, and video is recorded onto the computer’s hard drives in a special video format.
Sometimes people are confused by this term because a number of years back a device that attached an analog camera to the networks was also called a video or camera server. Now that’s known as a Video Encoder.

Caller:  Yes, I was confused by that myself. Now what about the NVR?
Engineer:  A NetworkVideo Recorder, or NVR, is a complete IP camera recording device. It includes a computer and special Video Management Software. VMS is required for recording video, but it also allows multiple viewers to monitor real time and recorded video.

Caller: I think I understand, but could you go over the differences between the Network Video Server and a Network Video Recorder one more time?

Engineer: Sure. The Video Server and Network Video Recorder are similar in that they both record video. The Network Video Recorder comes with the Video Management Software already installed.
 The Video Server does not include VMS. You select the software you like and load it.
The Video Server usually runs on a Windows operating system and it’s more flexible than the NVR because it is easier to expand and add cameras. The NVR, on the other hand usually has a fixed limit as to the number of cameras it can support.

Caller:  Okay, Got it. Now what about a DVR?
Engineer: The DVR or Digital Video Recorder is a device that records video from analog cameras to one or more hard drives. The term DVR is also used by the consumer TV market.
 The DVR used in the security market has a fixed number of BNC connections to attach cameras. DVRs are available with 4, 8, 16, 32, and 64 channels, or connections. This means that you have a maximum number of cameras that can be supported by one unit. Once you exceed the number of connections available on that particular DVR, you will need to add another DVR to your system.
 There are some DVRs that can connect to the network, and be viewed using a Windows computer.

Caller: Uh-huh, so what’s difference between a DVR and a NVR?

Engineer: There are several differences but let’s start with these:

  • The NVR connects to the computer network along with the IP cameras. So you can take advantage of the existing network infrastructure, meaning you don’t have to run wire from a home base location.
  • The DVR uses coaxial connections to each of the analog cameras.
  • The NVR supports high resolution megapixel cameras
  • The DVR supports only cameras with VGA resolution

Caller: Do they all let me store pictures on my hard disk for later viewing?
Engineer: Always with a NVR, and with the Video Server and DVR, as long as you’re using VMS.  Also, if you’re using VMS on your Windows compute, you can usually distribute the storage across a number of different hard drives on your network. It depends on the VMS.
But no matter which VMS you use, storing images every second, around the clock means storing a lot of pictures that are exactly the same. So you’re using valuable space to no avail. One way around that is to have a motion detector starting and stopping the recording. Another space-saving alternative is to reduce your frame rate.

Caller:  Okay, let’s talk about this software. What do I need?
Engineer:  There are a number of VMS products out there. The main job of any Video Management Software is to record the video from many IP cameras on the network. It is very important to select software that’s reliable and doesn’t crash. Imagine how you’d feel if you lost important video. It’s also important to use a dedicated computer system to run the software.
The various VMS products available have many additional functions, including motion detection, sending special alerts to tell you if something important has happened, flexible displays of real time and recorded video, easy location and display of multiple recorded video channels. The features you choose depend on your particular objectives.

Caller: Do I need a network switch?
Engineer:  Yes. You may have to add a network switch if you don’t have any empty ports on your current switch, or if you don’t have a network switch installed. You require one port for each camera.  It’s best to use a network switch that includes PoE on all ports.

Caller: PoE? What’s that?
Power Over Internet (PoE)
Engineer:  The latest IP cameras get power over the network. This is known as Power over Ethernet or PoE. You can also add a PoE midspan, or a power injector between the switch and the camera.
Using PoE means you only need to run one network cable to each camera. That makes installation so much easier.

Caller: How about a video switch? Will I need that?
Engineer: No. The LAN network switch operates as the switch allowing hundreds of cameras to be viewed on a network.

Caller: Wow, Let me run this past my boss and I’ll get back to you as soon as we figure out which will serve us best.

Engineer: Would it help if I send you some specification pages and data sheets to help with your decision?
Caller. That would be great. Thanks so much for all the information?

Do you have any questions? Do you need clarification for any of the answers here? If so, our sales engineers can provide you with all the answers you need. They can also help you with IP cameras, Door access control, and IP paging systems. Call us at 914-431-1658 or fill out a request information form at http://www.kintronics.com/RequestInfo.htm

Virginia can be reached at virginia@kintronics.com