SDI (Serial Digital Input, serial digital interface) the ITU-RBT.656 and SMPTE (Motion Picture and Television Engineers) standard serial link, through a 75-ohm coaxial cable to transmit uncompressed digital video, SDI interface digital HD has matured in the field of broadcast video applications for high-definition video transmission and application provide a reliable and effective way.
SDI interface has today SMPTE259M (SD-SDI, data rates of 270Mbps), SMPTE292M (HD-SDI data rate of 1.485Gbps) SMPTE424M (3G-SDI data rate of 2.97Gbps) more than one standard. SDI interface of the system, there is no introduction of compression and decompression process, the transfer process does not need to consider the image temporal redundancy, and therefore, without the need of the video frame buffer, the video can be transmitted in real time. The camera sensor signal can be through the SDI interface, and direct access to the display unit without any loss. Compared with network digital HD, HD SDI interface-based video systems have the following advantages:
HD images without delay real-time transmission - did not produce the action of compression and packet during transmission, without coding and decoding, the system image does not produce the delay problem can be comparable with the real-time simulation system, the requirements of real-time monitoring occasions with the Network HD systems can not match advantage;
Lossless HD image without distortion - uncompressed digital image on the coaxial cable or optical fiber transmission, without distortion. Uncompressed high-definition image is the the intelligent monitoring best image sources. In addition, even if the epitaxial will not bring the network epitaxial SDI interface center system with front-end system is completely isolated, it is not possible after SDI interface generates network intrusion security over the network system. Further, since the video is transmitted in real time, does not appear video interrupt or delay, to avoid error information in the network system;
The system is easy to upgrade - similar to a traditional analog CCTV system, the distance permitted to replace the camera and back-end equipment can use existing coaxial cable, fiber optic lines, direct upgrade from analog to Full HD resolution. Dealers / contractors do not need to do additional upgrades network of knowledge and learning complex than conversion to IP network monitoring. SDI-based transmission systems, but also embedded audio information, and can support data transfer, easy-to-use site.
SDI Optical the HD SDI monitoring system necessary transmission equipment, how to identify the SMPTE-compliant SDI Optical puzzled many users, in fact, by the SDI pathological code test to verify. SDI Optical transmission characteristics when the signal in the transmission specifications bitrate barely available, but the time the problem of the the irregular transmission bit rate signal is immediately reflected problems in 1.5G rate (720P or 1080i application) low probability in 3G high probability rate (1080P Applications) problems, mainly for HD video transfer process sometimes splash screen, black screen, blue screen, can not guarantee smooth playback screen continuous cause these problems for two main reasons: First, the immature SDI Optical scheme or design defects account for a small part of this reason; Second, the cost factors, the market most of the SDI Optical the common SFP optical module, SFP optical
module with 1.25G rate and 2.5G rate digital instead SDI Optical the VIDIO SFP optical module, so that the inevitable transmission rate irregular when a large number of BER. SDI Optical fields of application higher screen quality requirements, naturally intolerable screen is not smooth, and so should be used for SDI Optical the VIDIO SFP optical module, in order to ensure that no splash screen high-definition image transmission, black blue screen and other phenomena.
SDI Optical video distributor, SDI HD video matrix are built into the line equalizer circuit for conditioning a plastic high-speed video signal will go through the cable transmission, and the whole process can ensure the real-time access to the rear end of the image data output of the photosensitive device, and reaches the switch matrix application control, and ultimately reach the monitor. Entire Optical transmission, signal distribution, high-definition video matrix switching control, networked video transmission process using high-speed serial digital signal transmission, transmission, switching process would not result in any image damage.
SDI interface with the corresponding standard, therefore, in the transmission, distribution, standard test equipment for the actual test process can be used, or can be used directly with SDI interface monitor video viewing determines the installation process may occur problems.
The signal is divided into multi-channel SDI Optical to enter the engine room, a video distributor, a group used to SDI matrix for local display and real-time upload to the law and order system at a higher level (such as the traffic police force, the police station, etc.); another group directly The transmission to the SDI encoder, video encoding, and then via the switching network, there is provided the use local storage or remote access to the backend platform. Given the large HD video code flow, each station should subnetting to shield the broadcast packet useless data.The SDI optical transceiver upcoming large number of applications in the field of high-definition monitor.
