Detailed explanation: The six shortcomings of IP network video surveillance system

The structure of the IP video monitoring system is simple, basically consists of various servers, and the wiring cost is low. In particular, a variety of signals can be transmitted on the same network. At the same time, it is very convenient to add monitoring points or clients. Only relevant equipment is needed. Access to the IP network can be, the openness of the IP system also allows users to use multiple ways to view monitoring video data anywhere, which brings convenience to the user is not comparable to the traditional analog monitoring system, due to various advantages, At present, the IP video surveillance system is almost an option for users to think about when building a new monitoring system. However, we must also look at the shortcomings of the IP system. In general, the IP system implies the following six major drawbacks:

Video quality After the original video is converted by analog to digital, it usually takes two paths—compressed or uncompressed. Due to the large amount of data after analog-to-digital conversion of the original video, it must be compressed before it can be transmitted on the IP network. Therefore, the video and audio signals in the IP video surveillance system are all compressed. The current video compression algorithm has advantages and disadvantages. It is lossy compression. The loss of video quality is an important reason why IP standard-definition video systems are difficult to popularize. Any person who compares analog video with coded video will see the difference. Of course, if the compression algorithm is not too bad, high-definition video will generally be better than standard definition analog video even after compression and decompression. Thin dead camels end up being larger than Ma Da.

Operational delay current mainstream H. The 264 algorithm has high requirements on the hardware performance of the codec device. Once the codec device cannot meet the requirements, the time required for encoding and decoding will increase, which will further cause video delay. The delay of the control will first bring about great inconvenience to the user's operation experience. Since the bandwidth after control signal compression is extremely small, the control command may be considered to be real-time relative to the video, if the delay of the video in the IP system is one second. When the user issues a PTZ control command, the front-end dome has responded to the PTZ command in a timely manner to start the rotation, but the rotated video takes 1 second to be seen by the user. In this second, the user will think that the dome camera If the PTZ code continues to be transmitted without rotation, the result may be a loss of control of the front-end PTZ and it is difficult to accurately position it. If the network environment is very poor, then the PTZ command to control the ball is likely to be lost, so that the front-end fastball can't really receive the order. In short, the delay of monitoring is an important factor that restricts the development of IP video surveillance systems. In some applications that need to monitor high-speed moving objects or require high real-time performance, such delays are unacceptable. Delay defects in IP systems are difficult to resolve in the future for a long time.

Security risks caused by openness The openness of the IP system is a double-edged sword, which brings great convenience to users and also brings great hidden dangers to the monitoring system. In an IP surveillance system, a video encoder or IP camera is often installed at the front end of the field. The video stream is transmitted to the monitoring center through the optical transceiver and other devices. That is, the signal transmission path of the IP system is open, and anyone can theoretically The transmission network that enters the monitoring system can also upload virus files through this route, which will cause great harm to the monitoring network and lead to the collapse of the system.

With the gradual promotion of IP systems, more and more professionals have noticed the security of IP systems. Since IP is a relatively mature and common technology, and the development of antivirus technology lags behind the development of viruses, the security of IP surveillance systems is foreseeable for municipal or public security projects with high security requirements. The future will be a major hidden danger.

QoS cannot guarantee that in the IP surveillance system, a large amount of video and audio signals are transmitted on the IP network. One of the characteristics of these signals is that they belong to liquid media. However, the principle of IP transmission and switching requires that these continuous media signals be interrupted and packaged separately. After the complex route is transmitted to the terminal. Due to the complex network environment, it is difficult to ensure that all data packets can reach the receiving end. This will easily result in the loss of image frames. It is reflected in the back-end is a mosaic and other fault phenomena, at the same time, there are multiple signals in the IP network, and the channel Bandwidth resources are also limited. How to ensure that the transmission bandwidth of video data packets is not occupied by other data packets is also a major problem. Once preempted, video transmission is blocked, which is reflected in the back-end is delay. Liquid media transmission over IP networks is a recently emerging application. Originally, IP network design could not be said to be a tailor-made transmission medium for surveillance video streaming media. Video streams are transmitted in such networks and service quality will be difficult. Guaranteed.

The complexity of related knowledge is not conducive to the engineering company or users to master the IP network involved in the IP video surveillance system. The knowledge is too complicated. It is difficult for the technicians of most product manufacturers who have come from the era of analog systems to master it. Needless to say, grass-roots engineering and technical personnel with different levels of knowledge, all of which will bring a lot of trouble to the design and construction of IP monitoring systems.

Coding and decoding algorithms are not unified The biggest problem in the current stage of IP surveillance systems is that the coding algorithms are not uniform. Even if the same algorithm is adopted, each practice is different. The direct consequence of this status is that the video codec equipment of different manufacturers cannot achieve it. GM also caused great inconvenience for procurement, construction commissioning and later expansion of project equipment. At present, this issue has attracted enough attention from the industry. The relevant international standardization organizations (ONVIF and PSIA) have also emerged. It is believed that this problem will soon be solved.

Looking at the development of monitoring technology, IP monitoring is an important direction for future development, and may even be the mainstream direction. This kind of architecture monitoring system will be widely used in metropolitan area projects, but taking into account the shortcomings of the IP mechanism itself, until these defects are effectively resolved, the IP surveillance system and even the IP transmission exchange mechanism are unlikely to be Transmission of important information over a wide area. Whether the defects of the IP system can be resolved quickly will depend on the voice rights of video surveillance services in various services based on IP networks. If video services gradually become important services in IP applications, then various vendors will seriously Consider the solution to the current deficiencies.