Todd Rockoff, Executive Director of the HDcctv Alliance, discusses managing storage from network, analog and hybrid devices.
The role of managing surveillance video has historically been dominated by DVRs. The increasing availability of network cameras over the last 10 years has motivated the introduction of hybrid DVRs, which manage video both from analog and network cameras. With the emergence of HDcctv camera connection technology, a new breed of hybrid DVR manages video from analog, HDcctv or network cameras. This article addresses the impact that HDcctv cameras might be expected to have on the designs of hybrid DVRs.
What is a Hybrid DVR?
A legacy analog system typically includes a collection of cameras, each sending analog video over coaxial cable to a DVR. The DVR is typically the nexus of a surveillance installation, the primary point at which the collection of evidence is controlled, and where system operators and investigators first review video. Many conventional DVRs offer Internet capabilities, so they and the attached cameras may be integrated, via a managed security network, with access control, fire alarms, HVAC systems and so forth.
The camera connection technology is the set of electrical and logical requirements governing the signaling between a camera and the DVR. Standards facilitate interoperability. The more completely specified the camera connection technology, the more readily interoperable the equipment placed at either end of the connection. The proliferation of IP surveillance systems has given rise to the introduction of NVRs, which are similar to DVRs but accept inputs only from network cameras. Fundamentally, a hybrid DVR combines disparate camera connection technologies, accepting inputs from a variety of cameras. Today's surveillance camera market is dominated by two camera connection technologies: analog and network video. Accordingly, hybrid DVRs accept inputs from both analog cameras and network cameras.
Conventional Hybrid DVRs Acc ommodate Both Analog and IP Video
In many modern video installations, the DVR has the capability to connect to the Internet. The Internet makes it possible to see and control video surveillance for any facility or collection of geographically distributed facilities from anywhere in the world. As a result, IP video has become a critical surveillance technology whose importance will only increase in the future.
The increasing importance of IP video, coupled with the desire to capture the high-resolution images that analog cameras cannot deliver, led to the introduction of megapixel network cameras that apply IP video as a camera connection technology.
Network cameras do not connect directly to the Internet; instead, they connect to a LAN within a facility and can communicate with the outside Internet via a router, hub or firewall.
Which Surveillance Customers Need Hybrid DVRs?
The relative merits of analog and IP video as camera connection technologies are a topic of industry debate that is beyond the scope of this article. The issues considered in the debate include the relative reliability, convenience, cost and performance of the competing camera connection technologies.
Irrespective of the outcome of that debate, there are two scenarios in which a conventional analog plus network video hybrid DVR is compelling, as outlined below:
1. Requiring High-Resolution Video
IP video as a camera connection technology enables high-resolution (megapixel) video, wherein the camera transmits around one million pixels or more per frame of video. Analog cameras cannot deliver megapixel resolution. In fact, analog video may be subject to a much lower theoretical maximum resolution at about 400k pixels per frame.
Therefore, an end user requiring high-resolution video has no choice but to specify IP video as a camera connection technology. The growing market demand for high-resolution video appears to be a driver in the adoption of IP video as a camera connection technology. This observation would be consistent with the proliferation of megapixel network cameras highlighted at the 2010 spring trade shows.
The owner of an existing analog system looking to upgrade to high-resolution video would be compelled to implement a LAN to add megapixel network cameras. Today's hybrid DVR offers the option to add some high-resolution cameras without throwing away all of the existing cameras, most of which may remain sufficient for the updated risk management requirements. That high-resolution capability is added to the video system at the cost of the added complexityof managing a LAN, which is more complicated to implement, maintain and troubleshoot than a legacy analog system.
2. Hedging Against Future Infrastructure Developments
Even there is no LAN available for adding IP video to an existing surveillance system, a hybrid DVR might be viewed as a purchase opportunity during a scheduled equipment upgrade to hedge against such time when a LAN might become available. The choice of the hybrid DVR over a conventional DVR becomes compelling in
this scenario, when the hybrid DVR can be obtained at no more than a modest price premium over the conventional DVR.
Even when hedging against future infrastructure developments, it might be important to consider that IP video and analog are fundamentally incompatible camera connection technologies. The introduction of network cameras to an existing analog facility typically requires implementing a LAN. LAN implementation is daunting in that it requires specialized skills to address the technical challenges it presents. Even if the needed skill set is available, LAN operation tends to be more expensive and require more hands-on management than a typical set-it-and-forget-it analog installation.
HDcc tv DVRs: A New Kind of Hybrid DVR
High-resolution video is one of the fastest growing segments in the surveillance equipment market. High-resolution cameras (defined as transmitting image resolution of 720p or 1080p, or about 1 or 2 megapixels) transmit up to six times more pixels per second than analog cameras.
Today the high-resolution video market is served primarily by megapixel network cameras. HDcctv has emerged as an alternative to IP video for camera connection in high-resolution video applications. HDcctv offers advantages over IP video as a camera connection technology for some applications, because it is more convenient to implement for existing video installations, less complicated to operate and intrinsically less costly. HDcctv preserves the operating paradigm of conventional video systems, while digitally delivering the highest quality video available.
The owner of a legacy system may wish to upgrade some, but not all, cameras to high-resolution video, or add new high-resolution cameras while preserving as much of the investment in existing equipment as possible.
Anticipating this requirement, many HDcctv DVRs accommodate both HDcctv and analog inputs. In the parlance of the HDcctv Alliance, the industry consortium managing the international HDcctv standard, an “n + m” hybrid HDcctv/analog DVR provides “n” HDcctv inputs and “m” analog inputs. Hybrid HDcctv/analog DVR configurations being brought to market this year include 1 + 4, 2 + 4, 4 + 4, 4 + 8 and 4 + 16, among others.
The ideal hybrid DVR allows the most appropriate cameras to be used to best advantage for a given application, whatever the camera connection technology implemented by each camera. Because the camera connection technology is not directly linked to video evidence management, the ideal hybrid DVR implements a user interface that treats all video identically, irrespective of the camera connection technology used to deliver that video to the hybrid DVR.