Here we show the difference between standard definition CCTV and High Definition CCTV.
Within two years, HD-SDI has established substantial awareness in the marketplace, as tangible products materialize from an earlier TV transmission concept. Market penetration, on the other hand, has been less than stellar, due to component/ system, pricing and deliverability issues. Is 2012 really the year of HD-SDI?
HD video surveillance is an unstoppable, irreversible trend. Indeed, it is one of the few driving forces behind growth in the global security market today, according to market research.
Previously, the only means to get HD surveillance footage was via megapixel cameras and IP-based networks. Although they gave rise to new contenders and business opportunities, traditional installers have been struggling with the lack of networking and IT know-how.
HD-SDI came as a boon for “the rest of us.” With characteristics similar to analog CCTV, HD-SDI provides an alternative to IP-based video surveillance. However, other than a select few subcontracted installations in China and Korea, HD-SDI currently does not have any large-scale applications to illustrate extended usability and manageability. Most players are still focusing their energy on stabilizing overall system performance, bringing down cost and educating the market, wedging their way onto the HD video surveillance arena.
Negligible Latency
Latency has always been the Achilles' heel for IP-based video surveillance. A key advantage of HD-SDI is its real-time delivery of every frame.
Of course, this is a priority that differs in each market. For example, Chinese end users have displayed extremely high interest in HD-SDI, although they may not full understand the technology yet. "HD-SDI has a bright future in China, since some vertical markets place higher value on its low latency. This is different than other regions, where latency in video surveillance is acceptable," said Wan Yun Feng, Project Manager, Winhi.
However, latency still exists for HD-SDI, contrary to what many claim, said Zou Yu Fan, Solution Manager, Axis Communications. "It is simply relatively less noticeable. As IP-based video surveillance continues to improve at a rapid pace, latency in HD network cameras is also becoming shorter and shorter, to the point that it is now barely noticeable."
Latency is no longer a big deal-breaker for HD network cameras, Zou continued. "Compared to other technical advantages of IP-based video surveillance, latency becomes a non-issue. In contrast, HD-SDI has limited transmission distance; remote surveillance still needs to be accomplished via IP networks, which introduces additional latency."
Zhou Sheng Qiang, GM of Video Surveillance at Keda Technology, commented on HD-SDI's low latency characteristic as well. "This supposed advantage of HD-SDI's low latency over IP-based video surveillance is very small. Latency in HD network cameras is already barely noticeable, so this particular advantage over IP-based video surveillance is really not a big issue at all. In larger installations, images come from wide variety of sources, and are delivered to the video wall chiefly via IP networks. HD-SDI is more a 'last mile' solution; video still runs through the networks in real-world settings, which still requires compression. The small advantage of having low latency is not a big deal."
Indeed, as bandwidth has increased over the years, network failures and latency issues have become much less common. However, even when the naked eye fails to acknowledge the latency, a few dropped frames can be the deciding factor in whether the system is effective. End users must decide what they value the most in a video surveillance system.
No Compression…Good?
HD-SDI contenders have also touted zero image compression as a key winning point over their IP-based counterparts. Raw data is indeed delicious, just like how fresh vegies and sushi are infinitely tastier than lesser, processed foods.
However, network camera manufacturers say the lossless video is merely useful when viewing in real time, and that storage still requires the images to be compressed via HD encoders or DVRs.
Furthermore, video analytics is based on the analysis of pixels. The data still needs to be digitized and compressed for it to be processed by the analytics engine. Ultimately, the images will still be compressed.
One problem that arises is that pressure is placed on back-end devices to process all the data from every camera, added Poseidon Technology's Zeng Chun Wei. "Back-end storage and processing are HD-SDI's weaknesses."
Although lossless video sounds like a sweet deal, there are some "gotchas" to be aware of. More efficient back-end storage and processing, as well as video analytics, are common issues that HD-SDI manufacturers must resolve in the near future.
Source: a&s International | Date: 06/27/2012
