Question The CCTV/Surveillance Expert

NVR vs. DVR
Q:
I’m finding the big decision for security managers is whether or not to network their video recorders. What do I tell them?

A: Standalone and networked options offer their own distinct advantages. For example, since network video recorders (NVRs) have no distance limitations, they are ideal for remote locations or for environments where cameras are widely distributed throughout the facility. DVRs (digital video recorders) may be the best choice in a facility where surveillance cameras are located only a few hundred feet from the station that the store manager is monitoring.

Another important issue is what type of cameras need to be supported. A DVR is recommended when there is a high density of analog cameras. However, if the organization needs to mix analog and IP devices, an NVR is a necessity.

NVRs also offer ease of integration with existing security infrastructure. Because an NVR, by definition, already exists on a network, its ability to integrate with other network devices is that much easier. Because DVRs do not require networking connectivity to operate with the camera, they’re not always situated in an area that has network connectivity.

The near future of IP holds the promise of enhanced image quality with the integration of mega-pixel cameras. For example, an analog DVR uses standard coax cables, which support a maximum resolution of 4 CIF. NVRs utilize IP network connectivity, which allow for the transmission of higher quality and larger format images. Since NVRs fit into an existing structured cabling model, this vastly reduces infrastructure costs. This is particularly important for top security areas such as casinos and high-value retail stores that often require mega-pixel cameras to make out the fine details of a person’s face or a card in a player’s hand, for example. These cameras are also being deployed at ports to capture images over a long distance and zoom in on details after the fact.

Users of NVRs can gain significant reductions in infrastructure costs with the adoption of Power over Ethernet (PoE), which acts as a conduit for both network communications and electric power. Facilities with legacy infrastructure can use injectors to obtain both power and data connectivity to their PoE cameras. However, this only works in environments with a few PoE cameras.Facilities with numerous PoE cameras would benefit from a CAT6e cable upgrade.

NVRs can take advantage of all the existing tools available to support IP, including wireless level 2 and level 3 devices, providing a wealth of opportunities to obtain inexpensive bandwidth from third-party providers such as traditional cable and telephone vendors that was not possible when they had to port live analog video via coax cables.

While many aspects of NVRs and DVRs, such as storage and search capabilities, are similar, the real difference lies in how NVRs can transform the security environment by enabling IP technology. However, the majority of video surveillance systems remain analog-based due to legacy investment, cost, and design simplicity.

An ideal scenario involves maintaining the ability to leverage both technologies in a single hybrid system. Video surveillance manufacturers have adopted various strategies to bring IP solutions to the market. It is important to choose a manufacturer that provides the most flexibility and leverages existing analog infrastructure while expanding to IP components where appropriate.

Peter Boriskin is the Director of Technology Access Control & Video Systems for TYCO.

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