All of the discussions in this blog so far have involved PAL and NTSC television standards, which refer to analog video signals. The majority of CCTV systems today would still have analog cameras, even though an increased number of manufacturers offer digital video (IP) cameras designed to “stream” video over network. The very few components in CCTV that, only a half a dozen years ago, used digital video were the framestores, quad compressors, multiplexers, and the internal circuits of the digital signal processing (DSP) cameras. Today, we can freely say that the majority of new installations, though still working with analog cameras, use digital video recorders for monitoring and long-term storage. Camera quality is an important starting point in the CCTV system video chain, but the quality of the recorded images and its intelligent processing have become equally important. In the interval since the first edition of this book (1996), there have been revolutionary developments in TV, multimedia, video, photography, and Rear View Mirror GPS DVR .
The majority of these developments are based on digital technology. One of the locomotives of the real new boom in Rearview Mirror has been the switch to digital video processing, transmission, and recording. This development gathered a real momentum in the last few years – hence the reason for a complete new edition of this book with extended discussions on digital, video compression, networking, and IP technology. Only a few years ago, the price of high-speed digital electronics capable of live video processing was unaffordable and uneconomical. Today, however, with the ever increasing performance and speed of memory chips, processors, and hard disks, as well as their decrease in price, digital video signal processing in real time is not only possible and more affordable, but it has become the only way to process a large number of high-quality video signals. Digital video was first introduced in the broadcasting industry in the early 1990s. As with any new technology it was initially very expensive and used rarely. Today digital video is the new standard, replacing the nearly half a century old analog video. It comes basically in two flavors – Standard Definition (SDTV) with the aspect ratio of 4:3 and the quality as we know it, and High Definition.
(HDTV) with the aspect ratio of 16:9 and around 5 times the number of pixels of SDTV. Many countries around the world are already broadcasting digital video, usually in both formats (SDTV and HDTV). Not surprisingly, the HDTV is going to be the preferred choice of the consumer market, owing to its much higher resolution and the theatrical experience one has watching movies, but since in the majority of CCTV today we use the standard definition resolution in this chapter, we will cover all the key features that refer to standard resolution video, with a 4:3 aspect ratio. Digital video recorders (DVRs) and IP cameras have now become the main reason for the new CCTV growth, a source of higher revenue and an inspiration for new and intelligent system design solutions that have blurred the line between computers, IT technology, networking, and Rearview Mirror DVR .
More information at http://www.jimilab.com/ .