Video transmission moves to next level
As network and digital camera use grows, so grows the need for transmitting these cameras' images in the fastest, clearest formats possible.
"What has always been an issue," explained Ben Donahue, director of product development for Axcess Inc., "is whether the bandwidth is large enough to allow most compression schemes to transmit reasonable frame rates at a reasonable resolution."
With image quality a key in security-related situations, slow-moving, blurry images aren't a viable option, industry experts noted.
Craig Scott, director of marketing and product management for Silent Witness, said the answers, however, may not lie in the time-honored solutions of building a bigger bandwidth pipeline and improving compression. "A lot of compression used for streaming video is not good for security," Scott added, "because you want picture quality."
Instead, he said, the key is looking for better network management of video.
One solution is to send a stream of video from the camera to a server in the middle of the network where the pipeline is larger. Cameras are typically at the end of the network pipeline, "where the pipes are narrower," he said.
By creating an IP camera that is a client, rather than a server, users won't need to sign on to the camera, he said, and will avoid the logjam of too many users trying to access video. "A web camera might allow four people to connect without degradation," Scott explained, "but it won't do it with 150."
Scott said the cost of a client-oriented camera is also lower, "because you don't have to have the server in the camera."
Donahue said digital video has marked the convergence of security with the IT network. More and more products, he noted, are making use of networks to transmit, and store video as well as access it from web page portals or "anywhere they can get connectivity."
Tom Kochenberger, senior CCTV technical specialist for Bosch Security Systems (formerly Philips CSI), said the cost of digital products continues to come down "due to the increase in volume and market competition."
In addition, he said, LAN-based systems are taking hold "due to the ease of installation and the ease of expandability."
Ed Davis, vice president-marketing for American Fibertek, said "everyone is talking digital," and the industry continues to see expansion in the technology.
In its area of concentration, the number of channels being transmitted over fiber optic lines continues to rise, Davis explained, from the current eight to where "12 and 16 are doable."
Also significant, said Davis, is that CCTV systems data "is going both ways."
Mike Girton, product manager for Optelecom, said one of the industry's current debates is between uncom-pressed analog images vs. video over fiber and video compressed on IP. Fiber, he notes, allows "virtually unlimited bandwidth," while MPEG over IP "has limitations."
With digital over fiber, Girton noted, "the picture remains perfect until the fiber gets too long," then it disappears. With analog images, he said, pictures will degrade over distance.
"Everyone knows the limitations of analog," added Silent Witness' Scott.
Another debate centers on the use of phone lines for transmitting video. While most observers see the eventual demise of video via phone, for the time being, the application will continue to exist, albeit as a shrinking market.
Scott said "there is an application for (video over) phone because some people believe the Internet isn't secure."
Alarm companies and central stations are also big users of phone lines, explained Axcess' Donahue. "It's a conundrum in the security industry," he said. "Most central stations are dial up, yet most want to offer these (video) services, but they don't have WAN, Internet connectivity."
Donahue said dial-up opportunities will exist for at least three to four more years "until central stations change over."
Optelecom's Girton said the company gets a few request for phone line-based systems, "but that will go away."
Also getting more notice these days is the use of unshielded twisted pair for video transmission.
Bosch's Kochenberger said "for many integrators, the big question is selecting the correct media for the job," whetherÃ‚Â that means coax, fiber optic, RF or UTP.
Bosch, he not-ed,Ã‚Â provides dealers and integrators "the pros and cons on the different media."
As a result, Kochenberger said, the security community is embracing new technologies as a way to save time and money as well as "allow them to offer their customers more global access to their security systems."
While acknowledging that "coax is still king," Girton said twisted pair can be an inexpensive alternative if it already exists in a setting where cameras are going to be added.
Guy Apple, vice president-marketing and sales for NVT, concurred that existing UTP makes it "possible to run lots of cameras at a low cost."
He noted the example of a grocery store chain that pre-loomed its store with UTP. "They have lots of dome spheres wired," he said, "so they can be relocated easily."
Twisted pair also offers certain technological advantages, Apple said, such as interference immunity and the ability to transmit over distances up to a mile.
Apple said several digital and network camera manufacturers, including Ademco, Kalatel, Ultrak and others have made or are making their cameras UTP compatible.
While acknowledging the benefits of UTP for distances and campus setting such as prisons and schools, Scott said "coax is still the choice for most people" citing statistics that show 87 percent of installations are still coax-based.
Also weighing in on the coax vs. UTP debate, Davis of American Fibertek, called coax cable "a safe harbor. People are used to using it."
UTP, Davis said, "lends itself to flexible architecture."
And while distance was the first reason customers moved to UTP, he said, it also has the added benefits of a clean signal, which doesn't face interference from other systems that are running alongside it.