There are many ways to monitor and transmit high-definition video. The purpose is to push video, audio, data, and other signals through the carrier to the place where they are needed. The stability of the transmission is the stable core of the video surveillance system.
First, the main transmission mode and characteristics of high-definition monitoring
With the development of networked, high-definition, intelligent and integrated monitoring systems, the monitoring and control system projects have also undergone continuous technological upgrading and innovation. As an integral part of the monitoring system, different transmission methods have different characteristics.
High-definition video surveillance According to different camera output signals, there are multiple transmission methods. 1. Network HD cameras: use standard Ethernet transmission, short-distance transmission using unshielded twisted-pair, long-distance transmission mainly through optical fiber or wireless. Optical fiber transmission uses Ethernet fiber transceivers, Ethernet switches, and PON equipment. Wireless uses 3G, 4G, WiFi, WiMAX and other methods.
The video transmission method in the network mode has the characteristics of small transmission bandwidth, low cost, and flexible networking, and is the main transmission mode of high-definition video surveillance. But at the same time, because the video is compressed, the details of the video quality, delay, and the clarity of the motion process are worse than non-compressed video. It is not suitable for some monitoring occasions that require higher video quality. . In addition, because the network mode itself is not very secure, the system is vulnerable to illegal access and attacks. It is necessary to consider the design of the network.
2. HD-SDI camera: High-definition digital component serial interface (physical interface is BNC), non-compressed. Short-distance transmission uses coaxial cable, long-distance transmission mainly through optical fiber, using HD-SDI high-definition optical transceiver equipment. Using HD-SDI to transmit video, the image quality is high, there is no codec delay, and the security is good. It is suitable for applications where there are high requirements for image quality and security. Because the transmission bandwidth of HD-SDI video is 1.485Gbps, the bandwidth consumption is high, especially when the number of large channels is transmitted is higher than the network mode. At the same time, the networking mode is also limited, and only point-to-point fiber transmission can be used.
Currently, in order to solve the HD-SDI bandwidth occupation problem, a visual lossless coding technology has emerged. It uses an HD-SDI interface on the interface, and performs visually lossless encoding of high-definition video during transmission, which can reduce the bandwidth to the original. 1/6 or so, at the same time does not affect the subjective experience of high-definition video, codec delay does not feel out. In this way, transmission costs can be greatly reduced. A single wavelength can support 8-channel HD-SDI video transmission. The networking mode can also support node-based transmission.
3, HDTVI, HDCVI camera: the use of analog transmission of high-definition video, image quality has reached high-definition, you can follow the original standard definition video coaxial cable, the system transformation costs low. Long distance transmission requires HDTVI or HDCVI optical transceivers.
According to the current development of the security industry, there are several common transmission methods for high-definition video surveillance:
The first is wired network transmission. Representative types include: high-definition network optical transceivers; switches combined with transceivers; EPON.
The second is wireless network transmission. The representative types are 2.4GWLAN and 5G network.
The third is non-compressed digital transmission. The representative types are SDI mode and MDI mode.
Second, how to ensure the effect of high-definition transmission?
HD monitoring is a unified whole, involving multiple aspects of the monitoring system, including front-end video capture, intermediate video transmission, back-end HD storage, display, analysis, and linkage. From the transmission link, how to ensure that the information is clear and effective?
Transmission is an indispensable part of the monitoring system. How can the video, data and other signals be guaranteed in the project during the transmission process? The individual thinks that the entire system video can be made clear and effective from the following points:
The choice of transmission scheme: Each transmission method mentioned above has its own characteristics, and the construction environment of the project system is not the same, so it is very necessary to choose the transmission method that accords with the project. For example, if the transmission distance is very long, optical fiber transmission should be selected. In the initial planning of the transmission scheme, taking into account the transmission bandwidth problem and the resource issues such as considering the total bandwidth of the entire system, such problems must be detected and confirmed according to the actual situation.
The choice of wire: This question personally considers one of the factors that are critical to the long-term operation of the entire system. For example: the transmission of SDI signals as a serial digital signal requires a very high transmission rate, and the use of this signal in the project is short. The transmission carrier of the distance will use the coaxial cable, but the specification of the coaxial cable is numerous, this time chooses the wire rod to be a test.
The choice of connector: As a connection bridge between cable and equipment in the transmission system, the quality of the device will directly affect the stable operation of the system; there are projects that encounter SDI and network transmission, among which the BNC video is selected in the SDI project. Inadequate results led to the slightest snow point, the network project due to the RJ45 head selection is not in place, leading to front-end camera disconnection; so the choice of the connector, need to arouse special attention; other factors: after the entire system is connected, The physical wiring of the line is normal, and it is easy to ignore the soft setting, which will cause the entire system to fail to operate normally.
Third, opportunities and challenges
With the development of 4K in the security industry, what challenges will the high-definition video transmission face? How will the development trend of high-definition video transmission in the next two years?
The 4K picture definition advantage makes everyone appreciate it, but the challenge is not small. First of all, the need for a higher resolution lens, as 4K × 2K IPC product supporting lenses need to reach at least 8 million more resolution, but the current few to achieve this standard, can be applied to the security industry is even less. Secondly, with higher network transmission bandwidth and greater storage capacity, 1080P HD H.264 streams are generally transmitted in security applications, requiring a bandwidth of about 4 Mbps. Under H.264 encoding, 4K resolution currently requires at least 12 Mbps or even higher bandwidth to meet the demand, and the storage capacity requirement also increases. Third, the higher performance of the encoding chip, according to the current chip cost performance, is clearly unacceptable to the security industry. Fourth, with stronger back-end decoding and display capabilities, back-end devices need more computing power than they are today. Fifth, larger resolution display devices, with at least 4K physical pixels, can render images without damaging the effect. For the current application technology, it is obviously not economical. Sixth, more powerful video processing capabilities will require more attention to detail. Although the development of science and technology is now unpredictable, we can also see some development trends from the history of the development of high-definition video surveillance.
In the future, as people's needs continue to increase, the demand for the definition of video will become higher and higher. Therefore, higher clarity is always the general direction of development. However, with higher clarity, the storage space is also increasing. Therefore, how to reduce the storage capacity is also a difficult problem for everyone, so it is also important to save the storage space. After that, it is the interconnection of information, because we are in the Internet era, and information is interconnected. Important, high-definition video transmission should be based on this background.
Fourth, the conclusion
With the development of technology, security in the future will gradually enter the 4K level image applications, combined with new intelligent analysis technologies, cloud data storage and mining technologies. As a high-definition video transmission application will also be tested, the future of network high-definition transmission technology requires higher bandwidth (front-end device Gigabit aggregation), higher chip technology (popular 4k chip), higher application platform ( Cloud data analysis), a more demanding work environment (combined with business monitoring of production applications in the first line), clearer images (monitoring images at the medical image level). The next two years of high-definition network transmission will inevitably combine application services, step-by-step boundary (preceding application analysis), networking (all adopting standard network architecture), intelligence (data mining analysis built in the transmission system), and software hardening ( Remove the operating system of the switch, use the quick and scalable curing system, and cloudize (the construction of security private cloud becomes the trend).
First, the main transmission mode and characteristics of high-definition monitoring
With the development of networked, high-definition, intelligent and integrated monitoring systems, the monitoring and control system projects have also undergone continuous technological upgrading and innovation. As an integral part of the monitoring system, different transmission methods have different characteristics.
High-definition video surveillance According to different camera output signals, there are multiple transmission methods. 1. Network HD cameras: use standard Ethernet transmission, short-distance transmission using unshielded twisted-pair, long-distance transmission mainly through optical fiber or wireless. Optical fiber transmission uses Ethernet fiber transceivers, Ethernet switches, and PON equipment. Wireless uses 3G, 4G, WiFi, WiMAX and other methods.
The video transmission method in the network mode has the characteristics of small transmission bandwidth, low cost, and flexible networking, and is the main transmission mode of high-definition video surveillance. But at the same time, because the video is compressed, the details of the video quality, delay, and the clarity of the motion process are worse than non-compressed video. It is not suitable for some monitoring occasions that require higher video quality. . In addition, because the network mode itself is not very secure, the system is vulnerable to illegal access and attacks. It is necessary to consider the design of the network.
2. HD-SDI camera: High-definition digital component serial interface (physical interface is BNC), non-compressed. Short-distance transmission uses coaxial cable, long-distance transmission mainly through optical fiber, using HD-SDI high-definition optical transceiver equipment. Using HD-SDI to transmit video, the image quality is high, there is no codec delay, and the security is good. It is suitable for applications where there are high requirements for image quality and security. Because the transmission bandwidth of HD-SDI video is 1.485Gbps, the bandwidth consumption is high, especially when the number of large channels is transmitted is higher than the network mode. At the same time, the networking mode is also limited, and only point-to-point fiber transmission can be used.
Currently, in order to solve the HD-SDI bandwidth occupation problem, a visual lossless coding technology has emerged. It uses an HD-SDI interface on the interface, and performs visually lossless encoding of high-definition video during transmission, which can reduce the bandwidth to the original. 1/6 or so, at the same time does not affect the subjective experience of high-definition video, codec delay does not feel out. In this way, transmission costs can be greatly reduced. A single wavelength can support 8-channel HD-SDI video transmission. The networking mode can also support node-based transmission.
3, HDTVI, HDCVI camera: the use of analog transmission of high-definition video, image quality has reached high-definition, you can follow the original standard definition video coaxial cable, the system transformation costs low. Long distance transmission requires HDTVI or HDCVI optical transceivers.
According to the current development of the security industry, there are several common transmission methods for high-definition video surveillance:
The first is wired network transmission. Representative types include: high-definition network optical transceivers; switches combined with transceivers; EPON.
The second is wireless network transmission. The representative types are 2.4GWLAN and 5G network.
The third is non-compressed digital transmission. The representative types are SDI mode and MDI mode.
Second, how to ensure the effect of high-definition transmission?
HD monitoring is a unified whole, involving multiple aspects of the monitoring system, including front-end video capture, intermediate video transmission, back-end HD storage, display, analysis, and linkage. From the transmission link, how to ensure that the information is clear and effective?
Transmission is an indispensable part of the monitoring system. How can the video, data and other signals be guaranteed in the project during the transmission process? The individual thinks that the entire system video can be made clear and effective from the following points:
The choice of transmission scheme: Each transmission method mentioned above has its own characteristics, and the construction environment of the project system is not the same, so it is very necessary to choose the transmission method that accords with the project. For example, if the transmission distance is very long, optical fiber transmission should be selected. In the initial planning of the transmission scheme, taking into account the transmission bandwidth problem and the resource issues such as considering the total bandwidth of the entire system, such problems must be detected and confirmed according to the actual situation.
The choice of wire: This question personally considers one of the factors that are critical to the long-term operation of the entire system. For example: the transmission of SDI signals as a serial digital signal requires a very high transmission rate, and the use of this signal in the project is short. The transmission carrier of the distance will use the coaxial cable, but the specification of the coaxial cable is numerous, this time chooses the wire rod to be a test.
The choice of connector: As a connection bridge between cable and equipment in the transmission system, the quality of the device will directly affect the stable operation of the system; there are projects that encounter SDI and network transmission, among which the BNC video is selected in the SDI project. Inadequate results led to the slightest snow point, the network project due to the RJ45 head selection is not in place, leading to front-end camera disconnection; so the choice of the connector, need to arouse special attention; other factors: after the entire system is connected, The physical wiring of the line is normal, and it is easy to ignore the soft setting, which will cause the entire system to fail to operate normally.
Third, opportunities and challenges
With the development of 4K in the security industry, what challenges will the high-definition video transmission face? How will the development trend of high-definition video transmission in the next two years?
The 4K picture definition advantage makes everyone appreciate it, but the challenge is not small. First of all, the need for a higher resolution lens, as 4K × 2K IPC product supporting lenses need to reach at least 8 million more resolution, but the current few to achieve this standard, can be applied to the security industry is even less. Secondly, with higher network transmission bandwidth and greater storage capacity, 1080P HD H.264 streams are generally transmitted in security applications, requiring a bandwidth of about 4 Mbps. Under H.264 encoding, 4K resolution currently requires at least 12 Mbps or even higher bandwidth to meet the demand, and the storage capacity requirement also increases. Third, the higher performance of the encoding chip, according to the current chip cost performance, is clearly unacceptable to the security industry. Fourth, with stronger back-end decoding and display capabilities, back-end devices need more computing power than they are today. Fifth, larger resolution display devices, with at least 4K physical pixels, can render images without damaging the effect. For the current application technology, it is obviously not economical. Sixth, more powerful video processing capabilities will require more attention to detail. Although the development of science and technology is now unpredictable, we can also see some development trends from the history of the development of high-definition video surveillance.
In the future, as people's needs continue to increase, the demand for the definition of video will become higher and higher. Therefore, higher clarity is always the general direction of development. However, with higher clarity, the storage space is also increasing. Therefore, how to reduce the storage capacity is also a difficult problem for everyone, so it is also important to save the storage space. After that, it is the interconnection of information, because we are in the Internet era, and information is interconnected. Important, high-definition video transmission should be based on this background.
Fourth, the conclusion
With the development of technology, security in the future will gradually enter the 4K level image applications, combined with new intelligent analysis technologies, cloud data storage and mining technologies. As a high-definition video transmission application will also be tested, the future of network high-definition transmission technology requires higher bandwidth (front-end device Gigabit aggregation), higher chip technology (popular 4k chip), higher application platform ( Cloud data analysis), a more demanding work environment (combined with business monitoring of production applications in the first line), clearer images (monitoring images at the medical image level). The next two years of high-definition network transmission will inevitably combine application services, step-by-step boundary (preceding application analysis), networking (all adopting standard network architecture), intelligence (data mining analysis built in the transmission system), and software hardening ( Remove the operating system of the switch, use the quick and scalable curing system, and cloudize (the construction of security private cloud becomes the trend).
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