What is HD?
The standard for measuring image sharpness is resolution, and the unit is pixel. The so-called HD, SD, the difference is reflected here. The dividing line between the two is megapixels or 720p, that is to achieve megapixels or 720p or more is high-definition, based on this standard, the current mainstream CIF and D1 video surveillance market are standard definition.
Whether it is from the perspective of resolution, display effect or fluency, HD has more advantages than SD. From the point of view of resolution, the resolution of deleting 720p is 9 times of the resolution of CIF, the resolution of 1080i/1080p is 20 times of the resolution of CIF. In the same display environment, HD will be much clearer; and from the display effect In terms of view, HD supports both large-screen display and 16:9 wide-screen display, which greatly enhances the user's viewing experience. In terms of fluency, HD supports higher frame rates, such as 720p and 1080i/1080p. 60 frames/S or 60 fields/S, so the image fluency is twice as high as standard definition.
Therefore, high definition instead of SD is inevitable.
However, in order to achieve true high-definition monitoring, it is necessary to fully support high-definition from the aspects of video source acquisition, video signal compression encoding, video browsing, and video file playback. The front-end adopts network HD camera access, which will cause the DVR of the storage link to make corresponding adjustments in terms of interface technology, image processing technology, and storage technology. There is no doubt that the evolution of video equipment is also in line with this trend.
In the traditional DVR era, video signal processing is divided into video capture and video coding. In the video signal acquisition part, most DVRs are analog video inputs and all use the BNC interface CVBS (ie, composite video signal) signal input. The maximum resolution of the composite video signal is D1. The DVR internally collects and quantizes the composite video signal according to the D1 resolution. High-definition video signals generally use analog component interfaces of YPbPrCrCb, or digital video interfaces such as DVI, HDMI, and HD-SDI. DVRs do not have such video interfaces. In the encoding part, the DVR can encode each channel's collected video signal to CIF, 2CIF, DCIF, D1, etc., but the maximum resolution of the encoding can only be D1, and it does not have the encoding capability of 720p or 1080i, 1080p. Therefore, traditional DVRs have been unable to match the front-end megapixel camera.
The DVR Development Process In 2000, China's first domestic DVR was launched, and DVR began to enter the Chinese security field. Subsequently, under the dual drive of technology and market, DVR began to develop by leaps and bounds. In 2006, DVR has occupied nearly 40% of the market share of video surveillance. DVR plays an extremely important role in the development of video surveillance from analog to digital. It can be said that DVR has created a digital surveillance era.
Since 2006, with the development of networked technologies and the intensification of information construction, the video surveillance industry has begun to enter the era of networking. The market is increasingly demanding for the DVR's networked functions and network adaptability. Under this demand, Some mainstream vendors have also begun to pay attention to network functions and launched DVS products. However, since the DVS product has a powerful network function, it has reduced local management and control capabilities, which obviously cannot cover the original market of the DVR. DVR, as a digital-analog hybrid product, has never been out of its semi-digital and semi-analogue. Therefore, the competition in the video surveillance market has become increasingly fierce, and product homogeneity has become more and more serious - the market is calling for a truly new generation of products. In monitoring the market demand for networking, in 2007, the concept of NVR (Network Video Recorder), a replacement called DVR, was frequently mentioned.
Some people think that NVR will replace DVR within three years. Some people say that DVR will not be replaced in a considerable period of time. Is it on DVR or on NVR? Let's take a look at the respective features and functions of the DVR and NVR.
DVR has the following characteristics:
1. The digitization of video and audio is realized and it is convenient for transmission and storage.
2, using computer systems as a carrier, use and operation more simple and convenient.
3, the use of modular hardware and software design, easy to expand and maintain.
4, digital video data can be long-term preservation and image quality will not be distorted.
5, video data playback and retrieval more convenient and quick.
Therefore, the DVR has truly replaced the VCR, marking the era of analog into the digital era.
NVR's full name is Network Video Recorder, and its core features are mainly reflected in the letter "N (Network)", that is, network characteristics. In NVR systems, the front-end monitoring point installs a network camera or video encoder. Analog video, audio, and other auxiliary signals are digitally processed by the video encoder and then uploaded to the NVR in the form of an IP stream. The NVR performs centralized video storage, management, and forwarding. The NVR is not subject to physical location constraints and can be deployed anywhere on the network. The NVR is essentially a "middleware" that is responsible for capturing video and audio streams from the network and then storing or forwarding them. Therefore, NVR is a completely network-based all-IP video surveillance solution that can be deployed on a network-based system.
In fact, in foreign countries, NVR products and technologies have begun to be applied in some high-end security areas. In China, professional security media and other theoretical circles have also added to NVR's grace, and the assessment of the development prospects of the NVR market is also extremely optimistic. However, in the past two years, the marketing of the entire network monitoring product did not seem to have achieved the expected results, which led to the domestic NVR industry going very slowly and very hard. So manufacturers and users have begun to wonder about NVR, network video surveillance, NVR and even the development of the entire network video surveillance industry go from here?
Let's start with a look at the difference between the NVR and the DVR.
NVR VS DVR
What are the advantages of NVR to "dial" DVR? Looking at the functions and features of NVR, there are several aspects that can be compared with "predecessors" DVRs.
Work mode The traditional embedded DVR system is an analog front end, and the monitoring point is interconnected with the center DVR in analog mode. Due to the influence of transmission distance and loss of analog signals, the location of the monitoring point also has great limitations and cannot be deployed remotely. . The NVR is a video monitoring system with a fully networked architecture. The monitoring point device and the NVR can be interconnected through any IP network. Therefore, the monitoring point can be located anywhere on the network and will not be subject to geographical restrictions.
For NVRs, they cannot work independently and become self-contained systems. NVRs need to work with front-end IP cameras or DVSs to implement storage and management of front-end video. For DVRs, analog cameras can be directly connected for video acquisition, compression, storage, and management, and can work independently on their own.
Because the DVR adopts an analog front-end, the center needs to lay out many lines such as video lines, audio lines, alarm lines, and control lines at each monitoring point. It is inattentive, and which line has a problem requires one manual troubleshooting. The workload of the wiring is rather tedious, and the larger the project size, the greater the workload and the higher the wiring cost. Compared with NVR, in the NVR system, both the center point and the monitoring point can be connected by only one network cable, which eliminates all the above-mentioned cumbersome lines including video lines, audio lines, etc., and the cost reduction naturally occurs.
DVR usually has a wealth of interfaces, including video input and output, audio input and output, PTZ control interface, alarm input and output interfaces, storage expansion interfaces, network interfaces, etc. These interfaces are essential for self-contained system DVR; For NVR, its function is located in the storage and forwarding of video, and is usually deployed as a "middleware" in the secondary room. It means far away from the scene, away from all types of video and audio input and output, far away from the alarm interface, and away from the workstation. Therefore, The deployment of redundant interfaces means increased costs and increased failure points.
Plug and Play For a long time, network products, including NVRs, have been masking the mystery of the Internet. They need to set up IP addresses, operate complex management systems, and so on. Now, using the NVR is no longer necessary. Just connect the Internet cable and turn on the power. The system will automatically search the IP front end, automatically assign IP addresses, and automatically display multiple pictures. It is better than DVR in the installation settings, but it is at least equal. .
DVR systems usually have their own functions such as video capture, compression, storage, and management. They can work independently from their own system. Therefore, they do not consider the compatibility of different manufacturers' systems and lack the “teamwork spiritâ€. Usually video encoding methods, network transmission protocols, video file systems, etc. are all privatized, which is not conducive to integration. However, based on the current high market share of analog surveillance and application rate, DVR can achieve true "plug and play", because the analog monitor and DVR interface is a very standard composite video (BNC) and PTZ control interface (485 ) Therefore, from this perspective, DVRs have better "openness."
An important factor that video storage DVRs are welcomed by users is that it has powerful video recording and storage functions, but this performance is still limited by its analog front end, that is, DVRs cannot implement front-end storage. Once a central device or line fails, video data is lost. There is no way to obtain it. At present, NVR products and systems on the market can support three kinds of storage methods: central storage, front-end storage, and client storage. They can also realize mutual backup between the center and the front-end. Once the center cannot record for any reason, The system will automatically transfer to the front-end for recording and storage. In terms of storage capacity, the NVR also has a large-capacity hard disk and a hard disk interface, network interface, and USB interface to meet the massive storage requirements.
NVR can be stored in various ways, such as DAS, SAN, NAS, etc. Various levels of RAID technology can be used for data protection, and the centralized storage of NVR is more conducive to the centralized deployment of storage devices, thereby reducing the cost of storage devices. Maintenance costs, room costs. In a DVR system, storage is usually performed by multiple hard disks or external disk arrays attached to the DVR, which is inconvenient for the deployment of centralized storage devices. However, it should be noted that because DVRs do not rely on network-based connections, network interruptions have no effect on their storage functions. NVR storage requires real-time network traffic. Once the network is interrupted, video recording data will be lost, or A front-end encoder/IP camera is required to have a local video data buffer function. Storage also determines the positioning of two products, small and medium-sized systems, and large-scale systems.
Security network products have long been considered as a security risk. Indeed, without a safe and reliable mechanism, the network is indeed a lot of trouble. However, in the network monitoring system, once security is ensured through the use of AES stream encryption, user authentication, and authorization, network monitoring products are completely free from the security concerns of the network. At present, NVR products and systems can already achieve these guarantees. In contrast, the audio and video bare signals transmitted by the DVR analog front end do not have any encryption mechanism and are easily intercepted. Once intercepted, they are easily displayed. come out.
The whole network management of the management NVR monitoring system should be said to be a major highlight. It can realize the whole process monitoring and centralized management of transmission lines, transmission networks and all IP front-ends, including the monitoring of equipment status and the browsing of parameters. The DVR is also the same. Because the center-to-front-end is analog transmission, real-time monitoring and centralized management of transmission lines and front-end equipment cannot be realized. When the front-end or line is faulty, it is inconvenient to verify the specific reason.
From the above points we can see that NVR is dominant! On the other hand, the current high-definition video sensor is mainly CMOS, and the CMOS sensor directly outputs a digital video signal. In the camera, the digital high-definition video signal is directly compressed and encoded by a DSP or an ASIC, and then transmitted in a network manner, which is more economical than the direct output of an ordinary high-definition camera. Based on the above reasons, high-definition cameras used for monitoring in the market are basically network cameras. Devices that can receive video and audio streams sent from network cameras and can store and browse locally are NVRs. Therefore, the evolution from DVR to NVR is a trend of high-definition surveillance. However, on the other hand, NVR is directly connected to the network and it is greatly affected by the network transmission bandwidth. This is also an important factor that restricts the development of NVR. In addition, compared with DVRs, NVR lags far behind DVRs in real-time video preview. The preview delay phenomenon is prevalent in NVR products currently on the market.
Looking at the video surveillance market as a whole, the NVR has a promising future, coupled with the product features that have a large market competitive advantage. However, it is not easy to really achieve this result. Compared with the product function alone, DVR has already been settled for several times. It has undergone severe market and time baptism, and its mature market awareness is current. NVR has no comparable. In addition, the domestic DVR market is fiercely competitive, with a large number of DVR manufacturers and varying levels, but on the other hand, competition has also prompted some high-quality mainstream manufacturers to continuously improve product performance and promote technological progress. They have not ignored the trend of the Internet era. . Although DVS differs from DVRs and NVRs in positioning, it at least shows that for NVRs, in addition to possessing technological advantages, the desire for the country’s major advantages requires accurate market positioning, rapid market response, and many other indispensable conditions.
In summary, although NVR is listed on the “scenery†under the attention of everyone with its technology and functional advantages, the current section of the road is still likely to be bumpy. In this game with the DVR, many factors such as technical performance, market channels, brand support, etc., must be treated with stringent scrutiny. With the DVR as a forerunner, we can only endure the pains in the early stage of market development, and it is possible to occupy the leading position of the DVR. Really become the market leader or even a substitute for the DVR.
The current market situation shows that a large number of analog cameras are still being sold and installed. The DVR application still occupies the mainstream. New video surveillance solutions represented by IP cameras and NVRs go much earlier in foreign countries. just began. The alternation between the old and the new requires a process. This process depends on the maturity of the IP video surveillance solution, the decreasing rate of the overall cost, and the acceptance of the IP video surveillance solution by the entire market and customers. This time may be three years. It may be 5 years or even longer.
The market application proves that DVR is now a heavyweight and representative product of digital surveillance. It is a mature front-end analog camera combined with back-end DVR acquisition code storage video. Although everyone can see that some companies in the industry have proposed the concept of “NVR Terminator†early, and the new NVR has been promoting, and foresee and analyze DVR will be replaced by NVR, becoming the new direction of the video surveillance market. However, under the circumstances that the NVR is not mature and fully popularized in the industry, the DVR is still the protagonist of the market. I think that the NVR is still a cloud relative to the DVR market.
The standard for measuring image sharpness is resolution, and the unit is pixel. The so-called HD, SD, the difference is reflected here. The dividing line between the two is megapixels or 720p, that is to achieve megapixels or 720p or more is high-definition, based on this standard, the current mainstream CIF and D1 video surveillance market are standard definition.
Whether it is from the perspective of resolution, display effect or fluency, HD has more advantages than SD. From the point of view of resolution, the resolution of deleting 720p is 9 times of the resolution of CIF, the resolution of 1080i/1080p is 20 times of the resolution of CIF. In the same display environment, HD will be much clearer; and from the display effect In terms of view, HD supports both large-screen display and 16:9 wide-screen display, which greatly enhances the user's viewing experience. In terms of fluency, HD supports higher frame rates, such as 720p and 1080i/1080p. 60 frames/S or 60 fields/S, so the image fluency is twice as high as standard definition.
Therefore, high definition instead of SD is inevitable.
However, in order to achieve true high-definition monitoring, it is necessary to fully support high-definition from the aspects of video source acquisition, video signal compression encoding, video browsing, and video file playback. The front-end adopts network HD camera access, which will cause the DVR of the storage link to make corresponding adjustments in terms of interface technology, image processing technology, and storage technology. There is no doubt that the evolution of video equipment is also in line with this trend.
In the traditional DVR era, video signal processing is divided into video capture and video coding. In the video signal acquisition part, most DVRs are analog video inputs and all use the BNC interface CVBS (ie, composite video signal) signal input. The maximum resolution of the composite video signal is D1. The DVR internally collects and quantizes the composite video signal according to the D1 resolution. High-definition video signals generally use analog component interfaces of YPbPrCrCb, or digital video interfaces such as DVI, HDMI, and HD-SDI. DVRs do not have such video interfaces. In the encoding part, the DVR can encode each channel's collected video signal to CIF, 2CIF, DCIF, D1, etc., but the maximum resolution of the encoding can only be D1, and it does not have the encoding capability of 720p or 1080i, 1080p. Therefore, traditional DVRs have been unable to match the front-end megapixel camera.
The DVR Development Process In 2000, China's first domestic DVR was launched, and DVR began to enter the Chinese security field. Subsequently, under the dual drive of technology and market, DVR began to develop by leaps and bounds. In 2006, DVR has occupied nearly 40% of the market share of video surveillance. DVR plays an extremely important role in the development of video surveillance from analog to digital. It can be said that DVR has created a digital surveillance era.
Since 2006, with the development of networked technologies and the intensification of information construction, the video surveillance industry has begun to enter the era of networking. The market is increasingly demanding for the DVR's networked functions and network adaptability. Under this demand, Some mainstream vendors have also begun to pay attention to network functions and launched DVS products. However, since the DVS product has a powerful network function, it has reduced local management and control capabilities, which obviously cannot cover the original market of the DVR. DVR, as a digital-analog hybrid product, has never been out of its semi-digital and semi-analogue. Therefore, the competition in the video surveillance market has become increasingly fierce, and product homogeneity has become more and more serious - the market is calling for a truly new generation of products. In monitoring the market demand for networking, in 2007, the concept of NVR (Network Video Recorder), a replacement called DVR, was frequently mentioned.
Some people think that NVR will replace DVR within three years. Some people say that DVR will not be replaced in a considerable period of time. Is it on DVR or on NVR? Let's take a look at the respective features and functions of the DVR and NVR.
DVR has the following characteristics:
1. The digitization of video and audio is realized and it is convenient for transmission and storage.
2, using computer systems as a carrier, use and operation more simple and convenient.
3, the use of modular hardware and software design, easy to expand and maintain.
4, digital video data can be long-term preservation and image quality will not be distorted.
5, video data playback and retrieval more convenient and quick.
Therefore, the DVR has truly replaced the VCR, marking the era of analog into the digital era.
NVR's full name is Network Video Recorder, and its core features are mainly reflected in the letter "N (Network)", that is, network characteristics. In NVR systems, the front-end monitoring point installs a network camera or video encoder. Analog video, audio, and other auxiliary signals are digitally processed by the video encoder and then uploaded to the NVR in the form of an IP stream. The NVR performs centralized video storage, management, and forwarding. The NVR is not subject to physical location constraints and can be deployed anywhere on the network. The NVR is essentially a "middleware" that is responsible for capturing video and audio streams from the network and then storing or forwarding them. Therefore, NVR is a completely network-based all-IP video surveillance solution that can be deployed on a network-based system.
In fact, in foreign countries, NVR products and technologies have begun to be applied in some high-end security areas. In China, professional security media and other theoretical circles have also added to NVR's grace, and the assessment of the development prospects of the NVR market is also extremely optimistic. However, in the past two years, the marketing of the entire network monitoring product did not seem to have achieved the expected results, which led to the domestic NVR industry going very slowly and very hard. So manufacturers and users have begun to wonder about NVR, network video surveillance, NVR and even the development of the entire network video surveillance industry go from here?
Let's start with a look at the difference between the NVR and the DVR.
NVR VS DVR
What are the advantages of NVR to "dial" DVR? Looking at the functions and features of NVR, there are several aspects that can be compared with "predecessors" DVRs.
Work mode The traditional embedded DVR system is an analog front end, and the monitoring point is interconnected with the center DVR in analog mode. Due to the influence of transmission distance and loss of analog signals, the location of the monitoring point also has great limitations and cannot be deployed remotely. . The NVR is a video monitoring system with a fully networked architecture. The monitoring point device and the NVR can be interconnected through any IP network. Therefore, the monitoring point can be located anywhere on the network and will not be subject to geographical restrictions.
For NVRs, they cannot work independently and become self-contained systems. NVRs need to work with front-end IP cameras or DVSs to implement storage and management of front-end video. For DVRs, analog cameras can be directly connected for video acquisition, compression, storage, and management, and can work independently on their own.
Because the DVR adopts an analog front-end, the center needs to lay out many lines such as video lines, audio lines, alarm lines, and control lines at each monitoring point. It is inattentive, and which line has a problem requires one manual troubleshooting. The workload of the wiring is rather tedious, and the larger the project size, the greater the workload and the higher the wiring cost. Compared with NVR, in the NVR system, both the center point and the monitoring point can be connected by only one network cable, which eliminates all the above-mentioned cumbersome lines including video lines, audio lines, etc., and the cost reduction naturally occurs.
DVR usually has a wealth of interfaces, including video input and output, audio input and output, PTZ control interface, alarm input and output interfaces, storage expansion interfaces, network interfaces, etc. These interfaces are essential for self-contained system DVR; For NVR, its function is located in the storage and forwarding of video, and is usually deployed as a "middleware" in the secondary room. It means far away from the scene, away from all types of video and audio input and output, far away from the alarm interface, and away from the workstation. Therefore, The deployment of redundant interfaces means increased costs and increased failure points.
Plug and Play For a long time, network products, including NVRs, have been masking the mystery of the Internet. They need to set up IP addresses, operate complex management systems, and so on. Now, using the NVR is no longer necessary. Just connect the Internet cable and turn on the power. The system will automatically search the IP front end, automatically assign IP addresses, and automatically display multiple pictures. It is better than DVR in the installation settings, but it is at least equal. .
DVR systems usually have their own functions such as video capture, compression, storage, and management. They can work independently from their own system. Therefore, they do not consider the compatibility of different manufacturers' systems and lack the “teamwork spiritâ€. Usually video encoding methods, network transmission protocols, video file systems, etc. are all privatized, which is not conducive to integration. However, based on the current high market share of analog surveillance and application rate, DVR can achieve true "plug and play", because the analog monitor and DVR interface is a very standard composite video (BNC) and PTZ control interface (485 ) Therefore, from this perspective, DVRs have better "openness."
An important factor that video storage DVRs are welcomed by users is that it has powerful video recording and storage functions, but this performance is still limited by its analog front end, that is, DVRs cannot implement front-end storage. Once a central device or line fails, video data is lost. There is no way to obtain it. At present, NVR products and systems on the market can support three kinds of storage methods: central storage, front-end storage, and client storage. They can also realize mutual backup between the center and the front-end. Once the center cannot record for any reason, The system will automatically transfer to the front-end for recording and storage. In terms of storage capacity, the NVR also has a large-capacity hard disk and a hard disk interface, network interface, and USB interface to meet the massive storage requirements.
NVR can be stored in various ways, such as DAS, SAN, NAS, etc. Various levels of RAID technology can be used for data protection, and the centralized storage of NVR is more conducive to the centralized deployment of storage devices, thereby reducing the cost of storage devices. Maintenance costs, room costs. In a DVR system, storage is usually performed by multiple hard disks or external disk arrays attached to the DVR, which is inconvenient for the deployment of centralized storage devices. However, it should be noted that because DVRs do not rely on network-based connections, network interruptions have no effect on their storage functions. NVR storage requires real-time network traffic. Once the network is interrupted, video recording data will be lost, or A front-end encoder/IP camera is required to have a local video data buffer function. Storage also determines the positioning of two products, small and medium-sized systems, and large-scale systems.
Security network products have long been considered as a security risk. Indeed, without a safe and reliable mechanism, the network is indeed a lot of trouble. However, in the network monitoring system, once security is ensured through the use of AES stream encryption, user authentication, and authorization, network monitoring products are completely free from the security concerns of the network. At present, NVR products and systems can already achieve these guarantees. In contrast, the audio and video bare signals transmitted by the DVR analog front end do not have any encryption mechanism and are easily intercepted. Once intercepted, they are easily displayed. come out.
The whole network management of the management NVR monitoring system should be said to be a major highlight. It can realize the whole process monitoring and centralized management of transmission lines, transmission networks and all IP front-ends, including the monitoring of equipment status and the browsing of parameters. The DVR is also the same. Because the center-to-front-end is analog transmission, real-time monitoring and centralized management of transmission lines and front-end equipment cannot be realized. When the front-end or line is faulty, it is inconvenient to verify the specific reason.
From the above points we can see that NVR is dominant! On the other hand, the current high-definition video sensor is mainly CMOS, and the CMOS sensor directly outputs a digital video signal. In the camera, the digital high-definition video signal is directly compressed and encoded by a DSP or an ASIC, and then transmitted in a network manner, which is more economical than the direct output of an ordinary high-definition camera. Based on the above reasons, high-definition cameras used for monitoring in the market are basically network cameras. Devices that can receive video and audio streams sent from network cameras and can store and browse locally are NVRs. Therefore, the evolution from DVR to NVR is a trend of high-definition surveillance. However, on the other hand, NVR is directly connected to the network and it is greatly affected by the network transmission bandwidth. This is also an important factor that restricts the development of NVR. In addition, compared with DVRs, NVR lags far behind DVRs in real-time video preview. The preview delay phenomenon is prevalent in NVR products currently on the market.
Looking at the video surveillance market as a whole, the NVR has a promising future, coupled with the product features that have a large market competitive advantage. However, it is not easy to really achieve this result. Compared with the product function alone, DVR has already been settled for several times. It has undergone severe market and time baptism, and its mature market awareness is current. NVR has no comparable. In addition, the domestic DVR market is fiercely competitive, with a large number of DVR manufacturers and varying levels, but on the other hand, competition has also prompted some high-quality mainstream manufacturers to continuously improve product performance and promote technological progress. They have not ignored the trend of the Internet era. . Although DVS differs from DVRs and NVRs in positioning, it at least shows that for NVRs, in addition to possessing technological advantages, the desire for the country’s major advantages requires accurate market positioning, rapid market response, and many other indispensable conditions.
In summary, although NVR is listed on the “scenery†under the attention of everyone with its technology and functional advantages, the current section of the road is still likely to be bumpy. In this game with the DVR, many factors such as technical performance, market channels, brand support, etc., must be treated with stringent scrutiny. With the DVR as a forerunner, we can only endure the pains in the early stage of market development, and it is possible to occupy the leading position of the DVR. Really become the market leader or even a substitute for the DVR.
The current market situation shows that a large number of analog cameras are still being sold and installed. The DVR application still occupies the mainstream. New video surveillance solutions represented by IP cameras and NVRs go much earlier in foreign countries. just began. The alternation between the old and the new requires a process. This process depends on the maturity of the IP video surveillance solution, the decreasing rate of the overall cost, and the acceptance of the IP video surveillance solution by the entire market and customers. This time may be three years. It may be 5 years or even longer.
The market application proves that DVR is now a heavyweight and representative product of digital surveillance. It is a mature front-end analog camera combined with back-end DVR acquisition code storage video. Although everyone can see that some companies in the industry have proposed the concept of “NVR Terminator†early, and the new NVR has been promoting, and foresee and analyze DVR will be replaced by NVR, becoming the new direction of the video surveillance market. However, under the circumstances that the NVR is not mature and fully popularized in the industry, the DVR is still the protagonist of the market. I think that the NVR is still a cloud relative to the DVR market.
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