Which Camera to Choose: HD-SDI Cameras or Megapixel IP Cameras?
Which camera will be more suitable for future video
security system: HD-SDI cameras or Megapixel IP cameras? This is a hot topic widely discussed among manufactures, end-users and media. As both HD-SDI cameras and IP cameras
are with megapixel resolutions and both of them are hot cameras in video security field.
IP cameras can achieve the video capturing, encoding, video stream network distribution and storage, embedded Web page contains video applications, and intelligent IP cameras even own intelligent
analysis functions consequently. IP camera has all the effect features of the video security system. So the video security
system can be constructed by only using the IP cameras in theory.
On the other hand, The function of HD-SDI camera
is only video capturing, which is identical to the traditional security analog cameras, and only change is the image resolution improved from D1 to mega pixels . So HD-DVRs is the core of this systems in the HD-SDI cameras based video security system.
HD-SDI cameras have two important points: image quality and latency of live video. Their live video has not been encoded,
the image quality is better than network cameras’ in principle, but it is only has mathematic meaning. There is almost
no difference between megapixel IP cameras and HD-SDI cameras as there is limitation for human eyes to identify image details.
As for latency of live video, it basically doesn’t exist for HD-SDI cameras. While for IP cameras, the theoretical
latency of network IP 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. So there is no practical difference between IP cameras and SD-HDI
cameras If IP camera developers pay enough attention to this problem and finally reach this theoretical minimum latency.
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.