System Considerations
One of the most attractive claims of using software is that you can greatly expand the number of cameras you can record on a given server. However, flexibility also introduces complexity, Lakshminarayan warned.
“The configuration, calibration and regular maintenance of the system are required to ensure it performs as specified. Vendors often talk about recording hundreds of cameras per server; they usually mean SD cameras using MPEG- 4 and only motion detection. Once you start using multimegapixel cameras, H.264 codecs and video analytics, the number of cameras per server drop dramatically.”
According to Lakshminarayan, key performance issues with video surveillance systems include:
? Dropped frames: Even if you set the frame rate to 15 fps, the camera may only be able to send 8 fps or the recorder may only be able to record at 7 fps. The network may not be designed to handle the data jitter and delay characteristics. The PC and video processing may not be able to deliver the horsepower required.
This may also lead to false alarms from video analytics, which could be very painful for users and cause them to ignore or turn off the analytics.
? Unresponsive system: The storage unit, recorder or camera may become very slow or unresponsive due to network or server-processing issues. The system may crash or need to be manually rebooted. During this time, if reliability, redundancy and resilience are not built into the design, there could be a lot of loss of data.
The IT world has had years of experience dealing with failing systems, and has long since realized that all systems will indeed fail. “The best way to solve these problems is by a careful, up-front design and building TCO into the system architecture. It is important to work with a design architect who understands the pitfalls and compatibility issues of the systems,” Lakshminarayan said.
Network Bottlenecks
The glaring bottlenecks of HD systems are network bandwidth and the required storage capacity, said Craig Howie, Commercial Director for Visimetrics. “Larger image resolutions coupled with high frame/bit rates, potentially low compression and probably multiple streams from each camera can leave a significant impact on network bandwidth, storage capacity and display performance.” With higher bandwidths, the network configuration or architecture becomes an essential element in the project design.
Bandwidth consumption from HD video is often several times that of its SD counterpart, said Xiang-Qun Ying, IP Camera Director for Hikvision Digital Technology. “For example, a 4-CIF image flows smoothly at just 1.5 Mbps, whereas a 2-megapixel HD camera needs more than 4 Mbps to make the clearer images useable. This places stress on both bandwidth and storage.” While this may not be a problem for smaller setups,networking becomes a headache when a large number of channels is required, and will need professional technicians to design and maintain the network.
HD network cameras often use 720p or 1,080p. In practice, these cameras require 2 to 8 Mbps of bandwidth for an acceptable and practical stream. When a system comprises several hundreds of these, the tremendous amount of data will need a well-designed network to avoid performance issues.
Regardless of equipment manufacturers, the most congested point in the network in terms of bandwidth usage within an HD system is between the cameras and NVR, Howie said. “For this very reason, it is always best to design the network architecture using a distributed storage methodology where the storage systems are located in relatively close proximity to the cameras, keeping the network congestion to as few hops as possible and definitely away from the core of the network.”
In addition, the cost of fiber optics is continuously dropping. A gigabit local network completely comprising fiber is much more achievable than a few years ago. The significance of bandwidth issues will decrease, as transmission technology is constantly and rapidly improving.
Storage Implications
The increasing adoption of IP-based video surveillance and the move to high-resolution cameras translate to more demanding storage needs for security and business intelligence applications. Frost & Sullivan estimates that this market will expand from US$123.1 million in 2010 to $181.1 million by 2016, citing demands for DAS, NAS and SAN solutions.
According to Frost & Sullivan, “IT storage for the physical security industry is still emerging, and dominant IT-based suppliers are modifying their existing enterprise IT storage offerings to suit physical security needs. As end users become more aware of these IT storage solutions and vendors gain greater expertise in serving the specific needs of the security industry, these solutions are poised to gain rapid momentum toward the end of the forecast period.”
However, the recent flooding in Thailand has hindered worldwide production, as the country churns out 40 percent of the world's hard drives. Average drive prices have already jumped about 20 percent because of the flooding, according to Bloomberg News . In a prepared statement, Stephen Luczo, CEO of Seagate Technology, said it will take a year, until the end of 2012, for production to recover to preflood levels.