DVR or NVR
Whether to specify a digital video recorder (DVR) or a network video recorder (NVR) is â€œthe million-dollar question,â€ admits Justin Lott, product marketing manager for digital CCTV, Bosch Security Systems, Fairport, N.Y.
Security dealers and systems integrators faced with the question have several options. The decision rests on the requirements of each job.
A rule-of-thumb is that the larger the installation, the more cost-effective networked video with NVRs or server farms may be. But some people donâ€™t agree with that, and where to draw the line is what can stump system specifiers.
â€œThe new buzz word is Internet protocol (IP), so everybody is pushing some type of an IP system,â€ Lott maintains. â€œIt is very challenging for a lot of these customers to decide what is the right thing for them. Thereâ€™s a couple of advancements that have happened that make the decision even more challenging.
â€œOnce you start getting into a larger system and more geographically spaced buildings, like office campuses and educational campuses, you start running into issues like, What if I have to add a user name and password and touch each of my digital recorders to put this user name in?â€ Lott asks.
In situations like that, networked digital recording becomes more practical, he points out. â€œI do believe IP technology and NVRs and so forth actually still are in the early adopter stage,â€ Lott maintains. â€œWhere that technology is new, they want the best of the best, the latest and greatest without realizing that digital recorders have made a lot of advancements, too.
â€œEven though they would be able to get by with a digital recorder system, some of them just want NVRs because that is what the industry is saying is the future,â€ he thinks.
â€œThe NVR is very much like a DVR, except the DVR takes an analog signal and processes, compresses it and stores it,â€ he continues. â€œAn NVR takes the stream directly from the IP camera and archives it, because the cameras are already putting out a JPEG or MPEG, so thereâ€™s no need to perform a compression at the NVR side. So in essence as far as integrating, our NVRs are almost identical to DVRs except they donâ€™t have a capture board for analog video.â€
DVRs have BNC connectors for analog cameras, whereas NVRs use Ethernet cable, Collazo points out, although hybrid devices and systems are combining both (see accompanying article on page 60). â€œInterfacing to an NVR and DVR is very similar.â€
Despite the industry trend towards networking, not all systems need networks. For some applications, DVRs are the simple and direct solution.
â€œDVRs are going to be around for a long time because the vast majority of people donâ€™t have a network infrastructure they can rely on,â€ Lott maintains. â€œThey want to simply record good video and view it when they need to. Many people donâ€™t want a PC running software because of the extra cost. And even if they have an existing PC, it may not be powerful enough to handle the graphics.â€
DVRs are still used extensively at dealer ADS Security LP, Nashville, Tenn., reports Lynn Davidson, commercial installation manager. â€œWe are still into the DVR section of the business,â€ he notes. One recent installation was a 32-camera DVR with 1 terabyte of storage space, Davidson relates.
â€œThese DVRs are a heck of a lot more stable than the old time-lapse VCR equipment,â€ he maintains. â€œIf some customer has ever asked one of our salesmen for a network recorder, it has not gotten back to me.â€
â€œDVRs and NVRs share many things in common, but they have different sweet-spots,â€ Lott declares. â€œUnderstanding their respective strengths and weaknesses is key to choosing the right solution to solve the problem at hand.â€
More ReliableBob McCarthy, vice president of technology for Dedicated Micros, Chantilly, Va., emphasizes the reliability of DVR use. â€œMost DVR vendors are trying to support DVRs that digitize the video and compress it and store it right there rather than sending it to some centralized storage spot on the network, which I would call an NVR,â€ he maintains.
â€œThe biggest reason people choose DVRs is theyâ€™re concerned that if the network goes down, they lose some of their evidence, because that is what it ultimately is used for,â€ McCarthy thinks. â€œA lot of stores are protecting themselves against fraudulent claims for injury or theft by employees or fraud from customers.
â€œSo people who get a lot of fraud claims or have very expensive ones arenâ€™t willing to lose video if the network goes down for an hour or a day, so they want their video to be local,â€ he explains.
Robert Siegel, general manager of video and software solutions for GE Security, Bradenton, Fla., agrees that DVRs are more reliable than NVRs.
â€œA lot has to do with what are the needs of the system and how much storage is required,â€ he thinks. â€œAn NVR is going to give you more programming flexibility and generally less reliability than an embedded system.
â€œThose paths are narrowing over time as systems become more and more reliable, but an embedded recorder will also give you something that is self-contained, be in one site and be more cost-effective than an NVR,â€ Siegel maintains. â€œDVRs generally have higher reliability. Embedded devices are more reliable but less flexible, and sometimes more cost-effective on smaller scales.
â€œNVR systems also tend to have benefits if you have multiple sites and locations, and theyâ€™re spread out and you want to do remote access and retrieval on a regular basis, such as a large transportation system, or bring data back to a central location,â€ Siegel notes. â€œAn NVR in a large-scale system might be more cost-effective, although thatâ€™s not always true. Sometimes, though, an NVR will give you more flexibility with easily moving video from several sites.
â€œThereâ€™s no easy answer to when an NVR becomes more cost-effective than a DVR â€“ it depends on the overall architecture of the system,â€ he asserts. â€œI canâ€™t give you a rule-of-thumb because it depends on the usage model. But if youâ€™re looking at 16 to 32 cameras, a DVR sometimes can be a better solution.â€
Memory capacity is no longer an issue between DVRs and NVRs, maintains Gary Perlin, vice president of video products for Speco Technologies, Amityville, N.Y.
â€œThe industry has learned how to put almost unlimited recording capacity into a DVR,â€ Perlin maintains, citing models with 1 terabyte of internal storage and unlimited external storage. He insists he can store the video of 15 cameras for a year at 16 images per second (ips) with a DVR.
â€œThe cost of that really is no higher than if I did the same thing on an NVR,â€ he asserts. â€œItâ€™s the same hardware, just in a different location. Price-wise, at the end of day, it will be very similar.â€
What Cable Already Is Installed?Sometimes the decision of whether to install a DVR or an NVR is determined by equipment already installed at a location â€“ for example, the type of cable.
â€œTypically, if coaxial cable exists in a facility, customers go straight to DVRs, and if coax does not exist, then customers are considering NVRs,â€ thinks Rob Morello, product sales manager â€“ digital systems for Pelco, Clovis, Calif. â€œThe trend taking place is a lot more complex than that, but if youâ€™re going to boil it down, those are the two areas.â€
He uses the example of an airport expansion where the new section may use NVRs but the old section still has DVRs or VCRs.
â€œOn a large VCR installation where you have a lot of existing coax cable, thereâ€™s a significant expense in redoing the infrastructure, so a lot of large VCR installations leverage their existing coax and install DVRs,â€ he notes. â€œFor the new installation, they install NVRs, and then theyâ€™re looking for a piece of software that can talk to both DVRs and NVRs.
â€œLogic would have it [that] over time you populate the NVR side of your equation and depopulate the DVR side of the equation, and over time what youâ€™ve accomplished is a seamless migration from analog to digital,â€ Morello relates. What is needed in this case is a solution that can pull video from either the analog or digital side seamlessly, he explains.
But Perlin at Speco Technologies does not think the cable already installed automatically determines whether DVRs or NVRs should be used.
â€œIf you would walk into a building pre-networked, that doesnâ€™t automatically mean you will go to an NVR,â€ he emphasizes. â€œUsing your own security system seems to be a trend now to get it off the IT guyâ€™s back so youâ€™re not fighting with them.
â€œOnce you decide you have to put in your own cable, the difference in cost between putting in coax or Cat 5e is not that significant for someone who sells for both industries,â€ he stresses. â€œLabor is the cost.â€
Perlin prefers coaxial cable from camera to recorder because of its greater bandwidth. â€œCoax is able to send analog signals in real-time high-resolution,â€ he notes. â€œCertainly networking from the DVR out to the world is realistic, but networking from the camera to the recorder is greatly overblown. Itâ€™s still an analog world out there.â€
Boschâ€™s Lott thinks video over IP is good for three things:
A virtual matrix in which many cameras are linked to many monitors, both analog and plasma monitor walls, referred to as â€˜soft monitors;â€™
Point-to-point â€“ using the network as an extension cord;
Geographically dispersed systems, where reusing structured network cabling can cost half of what it would to lay dedicated coaxial cable. Such systems are easier to change, and they can reuse off-the-shelf networking advances like wireless, laser and microwave.
Viruses and WormsAnother consideration McCarthy notes with employing DVRs that use the Windows operating system is vulnerability to computer worms and viruses.
â€œA lot of people see PCs as being very vulnerable to network attacks and maybe being crashed,â€ he maintains. â€œThe first DVRs all used Windows, and some of the newer ones coming out are not, because a lot of customers are very sensitive to having their security systems running on a Windows PC.â€
McCarthy estimates roughly half of DVRs use Windows and others use operating systems such as Linux.
â€œCompare the cost to what your security requirements are,â€ he suggests. â€œCan you risk losing video in transit or that is stored at that centralized site? What is the cost of transmission? Do you have to upgrade from one T1 line to a second T1, and what does that cost you every month?â€
Off-the-shelf ServersLott is familiar with companies that want to use their own servers to store video without DVRs or NVRs. This is being facilitated by companies that are providing NVR software by itself.
â€œSome of these companies have maintenance contracts and agreements with companies like Dell and IBM for storage farms and servers, so some people love the IP cameras and the experience from security and video expertsâ€™ point of view, but theyâ€™re IT experts as well, and they want to be able to handle that themselves,â€ he notes.
This is the advantage of companies whose video equipment has open architecture, he points out. They are able to connect with other companiesâ€™ servers, even those not in the security industry.
The disadvantage of this approach for the end user is that if a problem develops, the security supplier does not take responsibility for the whole system as it would for its own equipment, Lott points out.
But Pelcoâ€™s Morello advises, â€œVideo files are so large whatâ€™s happening is a lot of installations that use existing servers that are in place have a difficult time keeping up with the demands of video requests.
â€œIf you lose a drive and it goes into RAID 5, you suffer a 20 percent to 50 percent decrease in performance,â€ he maintains. â€œThose traditional servers out of the box are not designed for video applications.â€
Rebooting is more accepted among information technology (IT) people, Morello insists. â€œIf you have to reboot a machine, youâ€™re not recording, and if youâ€™re not recording, something bad could happen,â€ he points out. â€œSo the level of acceptance is much lower on the security side than the computer side. Do you want to take the chance of compromising your ability of getting video when you need it?
â€œThe trend is going more towards network-based solutions and using dedicated servers to handle that video, because itâ€™s not about storing, itâ€™s about storing and retrieving when you need it,â€ Morello maintains. â€œSo what good is it if you store video and it takes three or four days to retrieve it because you donâ€™t know where you put it?â€
Dedicated Microsâ€™ McCarthy points out other considerations with using server farms. Sometimes IT departments do not want to lose bandwidth on their networks to video, he adds, and although centralized video storage may be less expensive to buy, what additional costs are incurred?
â€œIf you have 100 DVRs and each has 100GB of storage, thatâ€™s 10TB,â€ he points out. â€œItâ€™s cheaper to buy a single 10TB storage box than a whole bunch of individual ones, so they assume some cost savings in centralizing it.
â€œIf you only look at the dollar amount of the hard drives, then yes, but if you consider that now youâ€™ve got IT staff that has to maintain and monitor the equipment and keep it upgraded, that will add to the cost,â€ he asserts.
GEâ€™s Siegel agrees. â€œA server farm technically is possible, but the question is, Is that a smart thing to do?â€ he asks.
â€œCustomers want their security systems to be a bit independent of their standard IT,â€ he thinks. â€œThat sometimes means separate physical wiring or separate virtual wiring, such as a firewall in between the two, and having things partitioned.
â€œAs weâ€™re adding complexity, itâ€™s up to us to make it simple to operate,â€ Siegel believes. â€œThis is an opportunity for integrators and for us to really develop a close relation with the end user by helping them understand what they can do with new security systems and demystify some of the new technology coming down the line.â€
Frank Ramos, product line manager for digital video recording, Honeywell Video Systems, Louisville, Ky., says his company is providing software expertise rather than the least expensive mass storage devices.
â€œWeâ€™re finding the price pressure is so great to supply those massive server farms or hard drive RAID arrays, weâ€™d be buying commercially available equipment,â€ he admits. â€œItâ€™s really the software that manages the video and archives it. We provide solutions rather than focusing on hard drives.â€
Ken Davis, manager, product management for digital video management systems, Tyco Fire and Security, American Dynamics brand, Boca Raton, Fla., has not seen many server farms actually in use.
â€œServer farms were a popular idea back in the dot-com bubble, but I havenâ€™t seen anyone come up with a server farm in an IT space â€“ it would be like outsourcing your DVR,â€ he asserts.
â€œWhat weâ€™re seeing more and more of is being able to integrate into third-party storage such as a network-attached storage (NAS) or a direct attached storage (DAS), so they can share storage and in a sense back each other up,â€ he relates.
â€œADT likes centralized monitoring where the video is most likely stored very close to where it is captured or at the customerâ€™s site, but managing and retrieving it is going to be centralized through a third-party DAS or NAS,â€ Davis explains. â€œThose generally are localized within an enterprise or corporate park.â€
Tim Rohrbach, vice president and chief information officer of MDI Inc., San Antonio, Texas, also likes centralizing data for large enterprise systems in a storage area network (SAN).
â€œIf I want to accumulate all that video to a central location, I have all the DVRs stream to it and access it there,â€ he suggests. â€œOr you can set it up so it records remotely at those sites and backs up on a scheduled basis to the SAN.â€
Side bar: Hybrid May Suit Todayâ€™s NeedsFrank Ramos, product line manager for digital video recording, Honeywell Video Systems, Louisville, Ky., is enthusiastic about DVRs that include network communication capability along with regular analog camera inputs.
â€œThereâ€™s a real trend now to a hybrid-type combination of the traditional DVR which can also record some IP-type streams, so you donâ€™t have to add a whole separate IP solution,â€ Ramos reveals. â€œThe DVR portion gives you a sense of security. It also can be distributed out, but thereâ€™s local recording there. If you lose your network connection, then you donâ€™t lose your video.â€
Ken Davis, manager, product management for digital video management systems, Tyco Fire and Security, American Dynamics brand, Boca Raton, Fla., thinks of hybrid systems as more than one device.
â€œMost of our larger customers, those who would tend toward IP systems, are using remote access and no longer just using the output directly from the NVR or DVR,â€ Davis explains. â€œThey are not connecting the monitor directly to the device but tucking them in a closet or server room and using remote software to manage the entire system or watch the entire system. Thatâ€™s a hybrid, and weâ€™re seeing a lot of that.â€
He is less sure about one combined DVR and NVR. â€œI think personally thatâ€™s a compelling feature, but I have not seen a great deal of demand for it,â€ he maintains. â€œI think thatâ€™s an interesting technology, but a network-based hybrid is more prevalent out there.â€
He also has seen early adopters connect an NVR to an encoder and a server in the same rack. That serves the same function as a single DVR, he thinks, but theorizes the end users who do this think they are future-proofing themselves by already having an NVR integrated into their system.