Video recording is one of the most important components of a video surveillance system. The video recording mode has gone from the original VHS video cassette recorder (VCR) to the currently widely used hard disk recorder (
DVR), and will eventually realize the all-digital
Network Video Recorder (
NVR) or "direct video to iSCSI" .
In recent years, with the continuous development of Internet, broadband network technology and information processing technology, server-based remote video surveillance, also known as network video recorder NVR, has greatly solved the transition from analog to digital systems. problem.
The so-called "network video recorder (NVR)" is actually a video storage solution based on network video transmission. In simple terms, the digital surveillance system first digitizes traditional video, audio and control signals and transmits them on the network in the form of IP packets. The network video recorder can receive video and store it anywhere on the network.
For a complete digital surveillance system, NVR should be a network video subsystem that contains basic storage hardware and centralized management software. The core advantages of the NVR include: First, the communications are all concentrated in the IP network, the interface is simple, the use of a standard integrated wiring system, installation and management is convenient; Second, focus on video data storage, a single coding component failure or control part Failures will not affect the entire recording system. Third, the architecture is flexible. It can realize front-end recording, centralized recording and operator client storage, and can realize multiple-point backup. Fourth, the network video stream is difficult to transmit during the original distance transmission. The quality is reduced due to interference. Fifth, RAID5 is adopted to improve data security. The system-wide centralized management based on IP network monitors all NVR working states in real time, and the entire system's storage capacity is flexibly allocated. Load balancing fully utilizes all storage space. , to avoid the shortage of storage space on some devices and excess storage on some devices.
Therefore, both the DVR and the NVR have great differences in the design of the supported signal types and products. DVR is more of a local operation and management application, taking into account certain network transmission functions. NVR is a network-based video data storage product. It has been designed to strip out unrelated management control functions and interfaces. The capacity is larger, more secure, and the system is more flexible. NVR is mainly used in IP digital surveillance systems.
At present, most video surveillance systems use analog cameras and analog video transmission. Applications are also concentrated on local operations and management. Cross-region monitoring needs are not numerous, and technologies, applications, and installations are relatively simple and mature. Therefore, DVRs The application actually occupies a major market share (more than 70% of the share). In China's central and southern markets in particular, due to fierce price competition, users and most engineering companies do not have sufficient knowledge of IP, and lack of trust in the stability of IP, they tend to adopt DVR video. In summary, its application areas are very extensive, including small-scale independent operation systems with DVR as the core and conventional simulation systems with matrix as the core. In general, DVRs can be used for projects with a small number of monitoring points, which are not far from the transmission distance and are mainly based on local monitoring and operation.
NVR is mainly used in IP digital surveillance systems. At present, the application of IP monitoring systems is relatively small, mainly concentrated in large-scale projects such as large airports, subways, highways, oil industries, large buildings, and bank central databases. The common features of these projects are the huge number of cameras, cross-region, long storage time, high storage security requirements, and rich system features. Therefore, with the increase in customer demand for IP across regions (landscapes), flexible architecture, and easy-to-manage network monitoring systems, more and more customers will adopt network video recording methods.
Simply speaking, the future direction of video recording must be moving from analog to digital and narrowband to broadband.
In the final analysis, the development of the NVR depends on the overall development of the IP surveillance system, including the popularization of high-definition and cost-effective
IP Cameras and codecs, high-performance broadband IP network facilities and construction, and the increase in customer demand for network monitoring.
We believe that the NVR will gradually erode and squeeze the DVR market, and it is expected that this transition period will last for a long period of time (5 years or longer). The reasons are as follows: First, the IP surveillance system is still not popular; Second, the price cost is higher than the traditional matrix, DVR; Third, the digital system compatibility of various manufacturers is still difficult to be compatible; Fourth, the emergence of new technologies may also replace the DVR And NVR, such as "direct iSCSI video storage technology."
Here, I have to mention iSCSI video storage technology. Personally, iSCSI is likely to become the terminator of the ultimate replacement of both DVRs and NVRs due to its stability.
iSCSI is an Internet TCP/IP-based network storage protocol developed by the IETF. iSCSI storage technology is currently the most widely used and most mature combination of iSCSI and TCP/IP technologies. Therefore, these two technologies make the iSCSI storage system an open architecture storage platform with very flexible system components. iSCSI is also actually a member of the SAN family, which can be used to build an IP-based SAN so that remote users can also share data and storage space in an iSCSI storage system.
iSCSI has more advantages and adopts iSCSI technology for video recording: first, the cost is less, the management is more convenient, and the maintenance cost is lower; secondly, it is more secure than the NVR network; and third, iSCSI is no distance limit. Fourth, the data transmission speed of iSCSI varies according to the speed of the Ethernet network. Fifth, the formation method is flexible and the scalability is high.
In short, with the continuous development of IP technology, more video and video recording technologies will surely be produced, but IP will inevitably be the end result of the digitalization process that starts with DVR.
July 24, 2021
