Network video surveillance is a relatively analog monitor and digital surveillance purposes, the analog monitoring system, image transmission, switching and storage are based on analog signal processing technology, the introduction of advanced digital surveillance digital signal processing technology to achieve with DVR as a typical representative of digital storage. The network monitoring with digital signal processing, based on a network-oriented approach to achieve signal transmission, switching, control, storage and on-demand video playback, and through the establishment of a strong central management platform (CMS), within the system to achieve all the codecs equipment and video storage devices unified management and centralized control. For users, just log in center management platform, you can achieve the unity of the whole network monitoring resources calls, browsing and management. Network video monitoring to achieve the end of the network, the system architecture consists of front-end IP, TCP / IP network, the center management platform, network storage devices, TV wall decoder, and client and several other components.
Video server from the core functionality can be divided into video encoder and video decoder two categories. Video encoders in network video surveillance system front-end, and the video decoder is located users to access client (or called back). Video encoder used to implement front-end signal (video, audio and other signals) digital compression and networking, specific functions include network monitoring point analog video and audio information and alarm information access, encoding / compression, transmission, and peripheral devices (such as cameras, PTZ, matrix, etc.) control. The video encoder of the information processed through the IP network to upload to a central management platform, and then distributed from a central management platform to the client, the video decoder and the video storage device. Video encoders and network cameras biggest difference is that the video encoder video source from an analog camcorder, you need to be used in conjunction with analog cameras, and network cameras are integrated, itself integrated analog video capture capabilities. From the current situation, even though the network camera is in large numbers, but because of two reasons, the video encoder will remain in the network video surveillance system occupies an irreplaceable position: First, a lot has been built analog and digital surveillance systems Urgent network transformation, in order to protect existing investments in analog cameras, these renovations will generate huge demand video encoder deployment; Second, the choice of network cameras currently face far analog cameras, it is difficult to meet the differentiated applications of different users demand, so many applications must be based on analog camera plus video encoder mode for front-end digital network. Video decoder is used on the PC under the control of the client receiving platform transmitted over the network video surveillance stream, decoded output analog signals to the TV wall, audio and other peripheral equipment, usually deployed in the user’s control center. The video decoder and the difference is that the client PC, the video decoder is generally based hardware decoding, through a dedicated network monitoring image display device to display, and PC clients directly monitored by the PC display image. Since the PC client and more control and management functions, and access to flexible operation, so the PC-based client applications to monitor browsing more and more common. However, due to the video decoder hardware-based, stable performance, image quality, so for a lot of need to focus on the application of decoding on the wall still has a very general sense.
Faced with an array of video servers, we are mainly based on functional requirements to select the appropriate video server products. First look at whether the product has the relevant qualifications, although the product does not fully represent the qualification of product quality and performance, but it is a lot of system integration project acceptance of the basic conditions, but also whether the product is qualified basic conditions; secondly transmission standard to meet the real-time activity image of the actual bandwidth demand, which is a measure of network video server an important indicator of overall performance. High-bandwidth network usage means increased costs for end-users, this will shake their determination using digital monitor mode, after all, is the economy of any business unit had to consider the issue; remote video transmission latency, although transmission delay of any kind of network video servers are inevitable, but different network video server latency values are different. Delay value will directly affect the effectiveness of digital network monitoring; regular monitoring and management software for the realization of functional integrity, complicated operation inconvenient, or even need special training to learn to master. Management software provides leadership for network monitoring and management of personnel or non-professional use simple WEB version control management software selection, IE Web form can provide single-screen image viewing, recording, control functions, users need to install specialized software, making monitoring image selected memory input without the complexity of different network video server IP address, simply download the WEB server to access the system control point name of the pre-set configuration information such as controls, mouse click to select the image name associated monitoring function can be achieved; Image Compression algorithm standard, the current mainstream network video server standard compression algorithms are MJPEG, MPEG-1, MPEG-4 three kinds;network monitoring center can simultaneously monitoring, recording video ones. As the network monitoring server used for remote network to multiple distributed, real-time, centralized monitoring, therefore, the monitoring center can simultaneously monitoring, recording video channels is a measure of the effect of remote centralized monitoring key indicators.In theory, an infinite number of simultaneously monitoring sites for the implementation of remote real-time image monitoring, recording. But in practical application by the monitoring center the actual network bandwidth limitations, such as the central network bandwidth of 10M words, assuming each video takes 250K, you can achieve up to 40 channels of video recording, unless the lower per-channel video bandwidth or increase the network bandwidth; Contractors warranty issue is one of the most concern, because contractors directly to end users, less than satisfactory after-sales warranty service will directly affect the project’s reputation.