Introduction to IP Video Surveillance / Network Video Recorders (NVRs)

IP Video Surveillance and Network Video Recorders (NVRs) are two of the most common terms describing the use of IP cameras and network based computers in physical security. Both of these terms are marketing phrases and are not controlled by standards body. As such, no authoritative definition is possible and many diverging opinions are held. This article attempts to document the most agreed upon assumptions and highlight the most widely debated elements.

Moreover, a debate exists in the industry over what to call these solutions. Reflecting the legacy of DVRs, many call these systems NVRs. However, this term suggests hardware and proprietary appliance. Many feel strongly that these solutions should be open architecture and 'software only'. As such, many do not consider their products to be 'NVRs'. Frequently manufacturers refer to their products as "IP Video Management" solutions or "IP Video Surveillance" solutions. For purposes of brevity, I use the acronym "NVR" in this document.

NVRs Must Support IP Cameras

Almost everyone agrees that to be designated an NVR a solution must support IP cameras. Indeed, the network in “network video recorder” is generally accepted as referring to the use of an IP network to connect IP cameras to an NVR.

NVRs are Software Only Applications (DEBATED)

Most NVR suppliers offer their product as software only. That is to say the NVR provides the user with installation files that are loaded on a computer of the user's choosing. The user does not have to purchase the hardware of the NVR supplier. This is widely considered to be a major benefit of NVRs and is referred to by Milestone Systems as busting out of proprietary jail. Choosing your own hardware can reduce total costs and increase flexibility to design and deploy a system that best meets your needs.

However, many NVRs suppliers do offer appliances. Appliances in IT refers to bundles of hardware and software that you must purchase together. A cellular phone is a common example of an appliance. You cannot mix and match phone software from one supplier and load it on the hardware of another. On the small scale, companies such as VideoProtein, offer appliances that offer the potential of reducing setup and installation complexity. On the large scale, companies such as Steelbox offers appliances that offer the potential of reducing costs and hardware necessary for deploying 100 or 1000s of cameras.

DVRs Cannot Support IP Cameras

By generally accepted definition, a product referred to as a DVR does not support IP cameras. The digital in “digital video recorder” generally refers to analog camera feeds being converted to digital inside of the recorder and therefore not being sent over the IP network. By definition, a DVR can only support analog inputs. Therefore, a DVR can only support an IP camera if the video feed from the IP camera is first converted back to analog using a 'decoder.'

NVRs Support Analog Cameras by Encoders

Encoders are appliances that converts the video feed from an analog camera into an IP stream that can be transmitted over a computer network like an email or a “You Tube” video. Almost all NVRs support encoders. Commonly held benefits of encoders include:

• Allowing existing analog cameras to be used with NVRs
• Eliminating the use of proprietary coaxial, twisted pair or fiber networks

Some Systems are Both DVRs and NVRs (DEBATED)

Some appliances support both IP cameras and directly connected analog cameras. Specifically, these appliances do not require encoders to support analog cameras. Analog cameras can be directly connected to the back of the appliance. This eliminates the need for encoders. Such appliances are generally referred to a hybrid DVR/NVRs. The main benefits cited for hybrid systems is that they can be cheaper than software only NVRs and that they ease the transition from analog cameras to IP cameras.

Many debate the validity of hybrid systems as true NVRs or IP Video Surveillance systems. Major concerns include the lock into proprietary hardware and the often incomplete choices of IP camera support and number of IP cameras a hybrid system can support.

All NVRs Support Certain Basic Functionalities

It is widely agreed that all NVRs support certain basic functionalities:

NVRs can Differ Significantly in Advanced Functionalities

While all NVRs are software applications, the software functionalities that NVRs offer can vary significantly. This variance can appear between suppliers and even amongst supplier's offerings.

For instance, Milestone Systems offers 4 categories of IP Video Surveillance / NVR solutions and a number of options. Examples of categories include:

• Basic: small camera systems, basic functionality
• Medium: medium camera systems, more advanced camera and system controls
• Multi-Site: large camera systems with servers in multiple locations
• Global: super-large camera systems with failover and central management

While all 'versions' offer basics like video recording, viewing and searching, different versions offer more powerful tools to improve reliability and usability as well as the number of cameras and locations supported. Likewise, significant differences can exist between NVR suppliers in the functionalities, reliability and scalability they offer.

NVRs can also differ in the types of options they offer. Examples include:

• Options for Different Verticals/Applications (Retail, Banking, Perimeter Protection)
• Options for Different Video Analytics (Virtual Tripwire, LPR, Facial Recognition)
• Options for Access Control integration, Central Alarm Management integration, etc.

Not all suppliers will support all categories and options. So, even within NVR solutions, buyers must examine what combination of features are most relevant for the operational and security needs they possess.

Large and Growing Number of NVR Suppliers

Worldwide, there are easily a few dozen suppliers of NVR solutions. That number is expected to grow as (1) DVR suppliers launch NVR offerings and (2) new entrants, attracted by growth, add offerings.