What is the difference between SD-CVI and HD-SDI in the security monitoring industry?

HDCVI technology is based on coaxial cable to transmit high-definition composite video signals, and adopts analog modulation technology to transmit high-definition video signals with resolutions of 1280H( 1280x720) and1920h (1920x1080) line by line. HDCVI technology has a bearing capacity of one million pixels, including 1280H@25fps, 1280H@30fps, 1280H@50fps, 1280H@60fps,1920h. The monitoring system using HDCVI technology can realize lossless and delay-free video and audio transmission and data communication between devices before the high-definition camera reaches the high-definition DVR, and ensure the reliable transmission of high-definition video within a distance of more than 500 meters.

HDCVI and HD-SDI

Compared with HD-SDI technology, HDCVI has a great competitive advantage in the field of coaxial cable transmission of HD video. First of all, both HDCVI and HD-SDI can transmit high-definition videos with effective resolutions of 720P and 1080P, but HDCVI has natural advantages in transmission distance.

First of all, in a good transmission medium environment, HD-SDI can transmit 100 meters. Even after the next version v2.0 of HDTV Alliance adopts compression technology, the transmission distance can only reach 300 meters in a good transmission medium environment. At present, HDCVI can transmit at least 500 meters with very low signal distortion when using 75-3 cable. Using 75-5 or better cable, the transmission distance can be further extended and the quality of transmitted video can be guaranteed.

Secondly, the anti-interference ability of HD-SDI is poor, especially in the environment of high-frequency radiation such as mobile phones and wireless routers. The strong interference of high-frequency wireless electromagnetic radiation on HD-SDI leads to high error rate of video data, which is characterized by abnormal image, open screen and inability to lock. HDCVI adopts low-frequency analog modulation technology, which essentially avoids the interference of high-frequency wireless electromagnetic radiation. Even in the environment of strong interference sources, high-quality image transmission can still be guaranteed.

Thirdly, in the actual construction, HD-SDI has strict requirements on the selection of wiring environment and construction methods, mainly in that the installed cables require high quality and are not allowed to be connected halfway; The welding quality of the terminal and the low radiation of the installation path put forward high requirements for the quality of construction personnel, construction cost, complexity of installation and maintenance, and wiring design. HDCVI technology follows the construction requirements and wiring specifications of analog standard definition, and ordinary weak current construction personnel can quickly deploy high-definition monitoring subsystem.

The relationship between HDCVI and IP

Compared with mainstream network high-definition cameras, HDCVI also shows the advantages of security industry applications.

First of all, HDCVI adopts point-to-point transmission to ensure the reliability of signal transmission. IPNC adopts Ethernet transmission technology, and the transmission path is routed and switched through the network, so there are risks such as network jitter and packet loss. In order to adapt to the network environment and ensure the fluency of video, video buffering technology is often used. At present, the point-to-point transmission with good network environment can be controlled within 300ms, and the delay phenomenon with poor network environment is more serious. HDCVI technology has no delay in point-to-point transmission, and the preview process of high-definition video source from camera to back-end equipment has not been encoded and decoded, and the image completely maintains the original effect, providing users with more perfect visual effects.

Secondly, the upgrade of analog SD equipment can also be seamlessly switched to HDCVI products, and the demand for comprehensive HD monitoring can be realized by replacing the camera and DVR. The construction and deployment mode of analog standard definition equipment is the most widely used, and it is the main system used by engineers and constructors in the current security engineering construction. HDCVI technology follows the transmission mode of analog standard definition, which is most easily accepted by users and quickly realized in construction and deployment. However, IPNC is similar to IT construction, which requires higher construction personnel, topology design, traffic design and node equipment selection.

Thirdly, the usage of HDCVI system is completely consistent with that of SD system. Analog camera and DVR deployment system are plug-and-play between devices, and DVR interactive operation is the main way. Compared with the use of IPNC, the camera often needs to be set and initialized, and there is also the risk of abnormal communication or configuration caused by network protocol compatibility problems. Even with the application of standardized protocols such as Onvif and the popularization of IPNC plus NVR system, its ease of use is still not as good as that of analog system.

In addition, due to the multi-signal cable transmission technology adopted by HDCVI, video and audio signals and bidirectional data transmission can be completed with one coaxial cable, thus realizing synchronous transmission of video and audio signals and reverse transmission of control signals, such as pan/tilt rotation and zoom control, and further reducing the complexity of construction and installation.

More importantly, HDCVI technology not only has practical value, but also adapts to long distance, no delay, strong interference transmission mode and complex deployment occasions, and has competitive advantages of low cost and high cost performance. The HD video surveillance system based on HDCVI technology will maintain the same cost as the original analog standard definition system, and experience the charm of HD surveillance at the same system cost.

Without compression and delay transmission, the image is clearer, smoother and more direct, and the monitoring effect is obviously better than that of network HD.

2. Pure physical layer, electronic system architecture without operating system, small size, low power consumption, and obviously better stability than high-definition network cameras.

3. Point-to-point physical connection is more stable, reliable and practical than network bus.

4. The return of uncompressed video data stream is convenient for back-end equipment to process, including display, switching and data analysis.

5. The high-definition digital signal is directly transmitted back several hundred meters to the MDI back-end encoder, and the back-end processor is used for double-stream or multi-stream high-definition coding, which saves the cost and enhances the reliability compared with the network high-definition video of each system (hardware and software) in the front-end.

6. The original digital video flows to the back end, which is convenient for direct display, and the compressed video stream does not need decompression, saving the DSP computing resources at the back end.

7. Use the same transmission medium (super Category 5 network cable or Category 6 network cable) without increasing the line cost. Save hundreds of meters of switching transmission.