- Expandability: Although both video servers and DVRs leverage existing investments in analog cameras, only video servers make total use of network infrastructure. This is particularly important when expanding the network video system, as an IP surveillance system is expandable in increments of one camera. A DVR on the other hand, is more difficult to expand. Once the capacity of a DVR is maximized, an entire new DVR box (usually with 16 or more channels) needs to be added to the system, even to accommodate one or two cameras.
- Wireless Functionality: Unlike DVRs, video servers allow users to create a wireless system. These systems can be expanded easily without the need to run additional coaxial cabling. This allows cameras to be placed in remote or difficult-to-reach locations that cannot be wired with coaxial cabling. For example, wireless transmission is useful in classified buildings, where the installation of cables would not be possible without damaging the interior. Wireless is also beneficial when camera locations need to changed frequently or when two sites need to be bridged without investing in costly ground infrastructure.
- Audio: While audio is now possible in a DVR system, it is much more cumbersome than with IP surveillance. DVRs create a system where audio is routed back to the DVR itself, while video servers allow the audio to be accessed from anywhere on the network. This allows users to communicate with visitors or intruders from any computer connected to the network.
- Future-proof: Video servers decentralize the digitization and compression functions found in DVRs. This helps process video faster because more information is handled at remote locations. It also opens the door for up-and-coming applications like intelligent video, which can be used in identifying abandoned luggage at an airport or reading a license plate number in a parking garage. A DVR cannot handle such applications because video is digitized and compressed in one location, creating a system in which centralized computer power is a scarce resource that cannot handle additional functions.
Video Servers in Action
Video servers are often used in professional security systems and enable live video to be viewed remotely by authorized personnel. Easily integrated into larger, complex systems, video servers can also function as stand-alone solutions in entry-level surveillance applications. Video servers can connect to the existing IP-network and enable real-time updates of high-quality video accessible from any computer on the network. Sensitive locations can be remotely monitored in a cost-effective and simple way, over the LAN or Internet.
For example, video servers have been used in installations as large as Sydney Airport's international terminal in Sydney, Australia, and in those as small as Canton High School in Canton, Miss. The airport used video servers to network hundreds of analog cameras, while the high school used the same technology to network just 24 cameras. Despite the difference in installation size, both end users were able to use the video server technology to improve their monitoring capabilities and now have the option of easily sharing video with the proper authorities via the LAN and the Internet.
Jim Walker, vice president of CameraWATCH, the company that installed the IP surveillance system for Canton High School, believes that the biggest benefit of video servers is the ability to view images in real time over the Internet.
"It's better than having a security guard at the school because a security guard can only see what is around him, and we can see all areas of the school at one time," said Walker. "The video servers also allow us to e-mail pictures to the police so that in case there is a problem, they know exactly what to look for."
For users searching to migrate from an existing analog CCTV system to the digital world, video servers provide a cost-effective, future-proof solution that goes beyond the functionality of DVRs. As IP surveillance continues to evolve, integrators will increasingly find that DVRs simply cannot meet client demands and fall short of a truly digital system.
About the author: As the general manager for Axis Communications, Fredrik Nilsson oversees the company's operations in North America. In this role, he manages all aspects of the business, including sales, marketing, business expansion and finance. He can be reached at firstname.lastname@example.org.