Then to Now – Network-centric Digital Video
I believe in a wise old saying that goes, “If you don’t know where you’ve been, it’s hard to know where you’re going.”
With that adage in mind, understanding and navigating the myriad of video storage solutions and the trend toward sleeker and more pared down centralized monitoring or command centers can better be achieved by looking at what developments were previously available and new options afforded chief security officers today.
A majority of video surveillance systems now in use typically consist of analog cameras, matrix switchers and multiplexed or standalone VCRs. While these systems provide basic monitoring and recording capability, they have several restrictions – limited quality and quantity of recording, no simultaneous recording and playback and the problem of where and how to store and manage all those VHS tapes. The advent of the digital video recorder (DVR) was a significant technological advance in addressing the problems of storage and retrieval as well as the management, quantity and quality of recorded data.
By internally converting the analog video feed to a digital format, DVRs can store the compressed video images to the unit’s internal hard disk drive or peripheral recording devices such as DVDs. Systems requiring higher quality, real-time video or extended storage periods require, RAID, NAS or SAN technology to be implemented. On-board or PC-controlled software allows for rudimentary database management for video retrieval and analysis. These hybrid systems (analog cameras/switchers and DVRs) signaled a change in the industry and revolutionized the notion of systems integration.
Using a common network platform and controlling software, access control systems, fire and alarm and even point of sale and ATM systems can now integrate with security video. All of the information gathered is stored on their respective devices with the ability to amalgamate the data for retrieval and advanced management. While this new configuration is light years ahead of the camera/VCR configuration, it presents a new challenge of working through a comprehensive.
New Storage SolutionsThe introduction of IP-centric digital video cameras has helped to eliminate some of these problems and provide new solutions for storage. Unlike analog cameras, IP video cameras perform image compression within the camera and data sent over to the recording device via an Ethernet connection. The conversion/compression function of the DVR is redundant with IP video cameras and these devices are now being replaced by network video recorders (NVRs).
Similar to a DVR’s features and functionality, NVR’s architecture is not restricted to installation in one room, but rather can be installed or distributed anywhere throughout the site where there is a connection to the network. For example, a fiber or even copper backbone in some applications can be tied into IDF closets or TR rooms containing camera power supplies and network switches, keeping cable costs and real estate back in the data center to a minimum. Additionally, if IP cameras are not in your plans, sites with analog cameras can use this same NVR system design by placing encoders that convert the analog signal to digital in the same closets with the network switch.
The advantage to the NVR in relation to archiving and retrieval is that it can usually be fully independent of storage and can run on either SAN (Storage Area Network) using multiple RAID units (redundant array of independent disks) or larger NAS (network attached servers), both of these options would be located in the data center. These devices increase storage capacity dramatically. This separate storage capability also helps to protect the video from hard disk drive failures through the added use of RAID Level 5 redundancy. In addition design can implement options to include backup or failover storage in the event a RAID goes offline. There are many variables that need to be considered when choosing a NVR or DVR and a storage solution to meet your needs.
While some enterprise security operations have turned to their IT department for assistance with on-going maintenance, due to regulations in some jurisdictions and the need for a broader knowledge in networked video, most will continue to have their own surveillance and security technicians remain in charge over the video network, servers and storage. In many cases, the technician’s skill set requirements have now evolved to also include IT and networking familiarity.