Network transmission stability and bandwidth impact delay
Network transmission stability and bandwidth impact delay
In addition to the important front-end surveillance cameras in the video surveillance system, the transmission and storage links also determine the quality of surveillance images. Especially in the Internet era, if you want to achieve high-definition monitoring results, in addition to high-end network surveillance cameras, in the video transmission and back-end storage, display must also be fully designed, how to achieve high-quality, no delay is the effect Current monitoring projects focus on solving problems.
In the monitoring system, the delay phenomenon is very obvious. This problem is attributed to two aspects: First, the current network monitoring bandwidth can not meet the bandwidth of a large number of image transmission, so the data will appear "queue" phenomenon; Second, in the storage process, according to different storage methods, compression methods, etc. will appear different Delay phenomenon, which causes the terminal display and the picture taken to appear a slight delay.
In the civil security market or home monitoring system, the small delay phenomenon does not have a great impact on the outcome of the event. If the delay occurs in financial and border areas, even a delay of 1 second may affect the human body. Property security poses a serious threat. Especially in the network remote monitoring system, even in the short 1s, something that we can not control may happen.
A network surveillance camera remote monitoring video capture
Returning to the above topics, let us now analyze why transmission and storage can cause delays in monitoring. Is there any way to solve the delay problem?
Network transmission stability and bandwidth
In the process of network transmission, the biggest problem that will affect the delay effect is the bandwidth problem. In the analog monitoring system, we do not need to worry about the delay, but in the network monitoring system, due to a large number of image information, the network is difficult to load for a time. I have also calculated such a value. The bandwidth required for a 1080p image signal at 30 frames/s is 1920×1080×16×30=995.328 M, which is approximately 1 G. From the perspective of the current transmission media, only optical fiber transmission is possible. The need for high-definition picture quality transmission, otherwise the bandwidth is too small to be susceptible to data transmission "queue" or "drop packet" problems.
Cloud storage can solve monitoring storage delay
In addition, although 3G wireless network transmission is strongly promoted, people who have experienced personal experience know that 3G network stability is still difficult to crack. Therefore, it is difficult to provide a connected network environment. It should not be a 1s or 2s problem compared to the delay problem. .
Editor's advice: Avoid wireless transmission as much as possible under normal network conditions. You can also choose analog and network "mix and match" styles when selecting a wired transmission method. SDI technology not only provides digital signals, but also does not compress codecs. Direct uploading, data lossless transmission and transmission without delay, can realize full HD presentation; in the short distance transmission process can also be completed with coaxial cable.
In the current survey, the storage delay often occurs in the process of storing large amounts of data. In particular, high-definition monitoring or safe city surveillance image storage is a great test for storage devices. In addition to the device's ability to read quickly, it also requires a strong output function, which ensures a high degree of rapid output while ensuring high image quality.
Some of the stored data is stored on cloud storage sites far from the server. These data are collectively referred to as "insensitive" data. They are less affected by the delay, but they are still affected by the network bandwidth and the server distance in the subsequent transmission process. Obviously, on cloud storage, a large amount of monitoring storage data is still not practical and cloud storage.
In the data delay, the general rating standard is within 400ms or 300ms, but from the current market, part of the transmission delay is around 1s is also very common. When long-distance, network bandwidth, storage, etc. become fatal to delay, it is not known when the next technology will appear.
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