HD-SDI cameras or megapixel IP cameras?
HD-SDI cameras or megapixel IP cameras?
It is a hot topic widely discussed among manufactures, end-users and media which one will be more suitable for future video surveillance system between HD-SDI cameras and Megapixel IP cameras as both HD-SDI cameras and IP cameras can reach megapixel resolutions, and both are hot products in video surveillance market. This article is to show Proline UK’s opinion.
The article will analyze and compare these 2 products from 6 aspects including function, capacity, cost, user-friendly and reliability.
Network cameras can achieve the video capturing, encoding, video stream network distribution and storage, embedded Web page contains video applications, and intelligent network cameras even own intelligent analysis functions. Consequently, network camera has all the core features of the video surveillance system, so video surveillance system, in theory, can be constructed by only using the network cameras. Some people might not agree with this conclusion: If the network camera can build the video surveillance system independently, what are NVR and VMS for? The reason of NVR’s existence is due to storage capacity shortage of SD cards of network cameras, and potential risk of SD card storage safety. As capacity of the SD card keep increasing and network security technology developing, there will be revolutionary changes of the video storage way in the future. The VMS system's main function is to centralized management of devices. This function can be distributed and deployed to network cameras while CPU performance getting higher and higher and the development of cloud computing technology. Therefore, in the network camera based video surveillance systems, network cameras are the core of the systems.
On the other hand, The function of HD-SDI camera is only video capturing, which is identical to the traditional CCTV analog cameras, and only change is the image resolution improved from D1 to mega pixels . So in the HD-SDI cameras based video surveillance system, HD-DVRs is the core of this systems.
HD-SDI camera’s advocates will emphasis 2 points: image quality and latency of live video.
HD-SDI Cameras’ live video has not been encoded, the image quality is better than network cameras’ in principle, but it is only has mathematic meaning. As there is limitation for human eyes to identify image details, so there is almost no difference between megapixel network cameras and HD-SDI cameras.
As for latency of live video, it basically doesn’t exist for HD-SDI cameras. While for network cameras, the theoretical latency of network cameras at 30fps is 140ms, and 60fps is only 70ms. However, in actual applications latency of network cameras is normally more than one second because of unstable network, If network camera developers pay enough attention to this problem and finally reach this theoretical minimum latency, then there is no practical difference between IP cameras and SD-HDI cameras.
A transmitter module, which modulating megapixel digital video signals to HD-SDI signals, is needed in HD-SDI cameras, while HD-DVR has a corresponding receiver module which demodulating HD-SDI signals to megapixel digital video signals, this is extra cost for HD-SDI system, but multiple HD-SDI cameras can share one video encoding chip of HD-DVR, while every network camera needs an independent video encoding chip. If it is possible to make cost down the multiple channel megapixel video encoding chips, it will compensate the extra transmitter and receiver cost of HD-SDI systems.
At present, the cost of HD-SDI modulating chip is high and the cost of multiple channel megapixel video encoding chips are also high, which leads to a high cost for HD-SDI systems. Anyhow, the chip price is based on volume. So which kind of camera has lower cost will be decided by market share.
A potential advantage of HD-SDI based video surveillance systems is that traditional surveillance systems can easily upgrade to new one by just replacing analog cameras and DVRs with HD-SDI cameras and HD-DVRs. However, the bandwidth of HD-SDI signal is far beyond the analog video signal. The re-wiring may be needed if the current coaxial-cables is not good enough. This potential risk of this problem is still uncertain.
Current society is an information society, all new buildings have considered a layout of information points, and it will become very easy to construct a IP network based video surveillance system. HD-SDI advocates sometimes claim the traditional installers have no idea of IP system. Actually, it is not as hard as they imagine. A lot of network integrators are considering expand to video surveillance, which will help system integrators of video surveillance greatly on the network construction. The advantage will be more obvious for those integrators with experience of network construction as the merge of the video surveillance and user’s other information systems are increasing all the time.
Some people are complaining the complicated configuration of network camera. Actually, it is not a Inherent problemfor network cameras. IT products’ user-friendly is up to the software design. By optimizing the software this issue can easily be solved.
In a HD-SDI based video surveillance system, an independent subsystem consist of a HD-DVR and several cameras connected, Failed HD-DVR will lead to all related surveillance points ineffective. In a network camera based video surveillance system, every camera is an independent subsystem, there is no depot point, so IP surveillance system is with higher reliability.
Some DVR manufacturers prefer to support HD-SDI cameras because they wish to maintain the existing DVR market share and products experience. The players from IT industry usually prefer network cameras because they expect to optimize their experience in networking industry. Which is the future, IP cameras or HD-SDI cameras? Proline UK thinks that it ‘s not necessary to make any final conclusion . What we need to do is to keep our eyes on both with an open mind. By analyzing both their advantages and disadvantages we can have a better understanding of video security market and can keep on providing customers with near-to-perfect video security solutions.