Interpretation of the difference between network video and HD-CCTV surveillance camera

Tag: Network Video HD-CCTV

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From the propaganda of the media, the voice of network video seems to be very high. In fact, in terms of technology maturity and image quality, HD-CCTV has advantages, but it is limited by the transmission bandwidth, and there are certain limits in the application range. At present, network video is mainly used in the networking of video surveillance systems. The focus is also on solving interconnections between networks, inter-system interoperability and inter-data interworking (decoding), etc., and does not propose better implementation of high-definition image transmission. Program.

HD-CCTV is developed from the SDI mode of the broadcasting and television system. From the perspective of system structure: it is an extension of the traditional monitoring mode. The core features are the closed circuit structure and the specificity of the transmission medium. The video stream output by the camera is not packetized or compressed, so the transmitted image is not distorted, not jittered, and has good real-time performance, and provides the best image for intelligent analysis of the image in the background of the system.

Such a structure facilitates the conversion of the system from SD to HD, from analog to digital smoothing. However, smooth conversion does not mean complete compatibility. The so-called "plug and use" is wrong. It is considered to be exactly the same as analog video. It is also wrong. The coaxial cable or BNC connector used in the system is completely different in performance from the products in the analog CCTV system.

The data stream of the SDI system is not a normal video compression coded signal, but a digital stream that converts parallel video component signals into serial sequential signals. Since it is not compressed, the data rate is high. Typically, SDI is a 270M system and HD-SDI is a 1.5G system. Therefore, the transmission distance is greatly limited, but with the advancement and application of optical communication technology, this will be significantly improved, and the application range of the HD-CCTV method will continue to expand.

Network video, using the digital video system of the network platform. Its characteristics are open, the system can be generated autonomously, and it is easy to expand and upgrade the system. At present, there are a large number of applications for video surveillance systems based on network transmission, but compared with analog video surveillance systems, there is no advantage in image quality.