视频监控视频监控服务器的特点与选购

视频监控服务器的特点与选购

Network video server, also known as video server, English name is DigitalVideoServer, hereinafter referred to as DVS, is video monitoring equipment, which is developing rapidly in recent years, with the development of network technology and the popularity of broadband network video monitoring will devour the traditional video monitoring equipment market share gradually.

Video server technology features

Although DVRS also have network monitoring capabilities, the current mainstream network monitoring device is the video server. It can put the analog video, audio or voice signal into digital signal and transmit through IP network, network video server at the same time also has alarm, yuntai control, etc.A lot of auxiliary functions. Video servers typically include audio and video collection, central processing, data encoding,network parts, and alarm cloud control. Because the camera output data at the DVS is analog signal, and in the network transmission signal to digital signal, so must go through A/D conversion of audio collection into digital signals. But, after A/D conversion, the digital signal and large amount of data,and the current domestic computer network bandwidth is limited,it is impossible to transfer A large number of data stream,which requires coding compression processing, in as far as possible to ensure that the image resolution of data compression at the same time, after being compressed into A small flow of data can be transmitted on the Internet. The network component needs to support network protocols such as DHCP, DDNS, UPNP, and NFS.

Some of the basic features of the current video server are.1, small machine. General analog video input is usually 1-4 road,not as a hard disk video recorder at a dozen road video input,and not random hard disk to carry and place your storage devices in the monitoring center is more advantageous to the image data storage and protection, this has saved a lot of space.2, simples. Through the development is rapid, economic and efficient computer communication network video data transmission to the monitoring center, only need a cheap five types of network cable, if you have any WIFI module, video server internal using wireless local area network (LAN) , so even the five types of network cable.

Strong central control. An industry standard server and a set of control management application software can run the whole monitoring system, the user as long as open a computer and Internet connection on the client program, enter the IP address of the corresponding video server inside can be fully remote monitoring. Any authorized client can access any camera directly or through a central server.

Easy to upgrade and extensibility. More cameras can easily be added, and the central server can be easily upgraded to faster processors, larger disk drives, and greater bandwidth.To a certain a certain type of products of the company as the example to specify the characteristics of the product size is 105 * 75 * 25 mm, smaller than the volume of a general network

camera, fully embodies the characteristics of the small machine video server; Using 1 road D1 / CIF video input, compression standard adopts h. 264 coding technology, compatible with PAL system and NTSC format, audio collection standard is 8kx16bitpcm, adopt a highly integration of arm9 and DSP processor chip, make the system more secure and reliable, data can be used in a 100 m front-end ports or wireless WIFI transmission. WIFI supports the 802. 11 a, b, and g communications protocols, while internally there is a 3G capability module that integrates the video server with the 3G mobile network. This product can not only through the cable but also through the wireless network data transmission, user can choose, fully embodies the characteristics of the video server products ease; Products with the client management application software, support network upgrade, but also in the case of network upgrade to support usb through U disk upgrade, fully embodies the characteristics of the video server powerful center control; In addition, the product itself has a common installation hole in the industry, which can be connected to a normal analog camera and a common tripod.

Through brief line connection between camera and DVS,eliminating the long distance overhead laying cable, fully embodies the characteristics of both economy and has a good cohesion.

Video server shopping guide

1, the picture quality

This is thebasic premiseof remotemonitoring, which is abasic

requirement for remote monitoring and unattended. Currently there are two kinds of quality CIF and D1 options on the market,which are 352 x 288 and 704 x 576 resolution. Of course D1' s DVD quality is ideal if you don' t consider other factors, but if you consider the bandwidth issue, the CIF can handle the requirements of some common situation.

When buying a product, it' s important to watch it online. The same D1, some products may be more than good CIF product effect is poor, so can't on the basis of parameter, must see in person,all parameters are to serve you in the eye, must be seeing is believing.

Different image bandwidth requirements

This is one of the important metrics to measure the overall performance of the network video servers. Because of the different image state (stationary, normal activity, high speed movement) , image resolution, send image frames, the network bandwidth difference is very big, so many in the network video server manufacturers recommend products, always tries to blur the index. To this, we can set up a state of relatively unified image, namely for the normal activity of image, image resolution of 352 x 288, frames of 25 frames per second, a video image of network bandwidth occupied.

3, IE monitoring function

The routine monitoring and management software is necessary to realize the integrity of the function, the operation is cumbersome, and even specialized training is required to master

it. Manufacturers should provide suitable for leadership or non-professional monitoring management using a simple WEB version of the monitoring management software to choose from,to offer Internet explorer WEB form single frame image monitor,video, control and professional users do not need to install the software, monitor the image when the choice does not need to input the complex of different network video server IP address, only need access to the system of the WEB server to download a set of configuration information such as the name of point to point control, the mouse to click select the relevant image name can realize monitoring function.

4, the network environment

When you buy a product, the first thing you need to do is to see what the product is and what the network environment is.Instead of buying blindly. If the network environment is not very good, and if you choose a product that is high on the web,there is no practical application. Like a Mercedes on a dusty mountain road, there is no room for manoeuvre.

Remote video transmission latency

Transport latency is inevitable for any network video servers,but different network video servers have different latency values. The delay value will directly affect the effect of digital monitoring. Therefore, to ensure the timeliness of the signal in the field, and the general bandwidth is not restricted,the product is required to remain in themicrosecond stage. That is to say, in the absence of bandwidth limit factors, the time delay of the video server itself to ignore, so it' s best to

within the local area network (LAN) , given enough bandwidth,test its performance.

The front-end snapping function

With low bandwidth, you can transmit high-resolution images via FTP. Namely USES the MPEG/H series compressed format image transmission, watch and storage after compression, video have move trigger, keep out of regularity alarm trigger behavior and artificial cognizance of alarm information, instantaneous in front JPEG format high-definition capture, a very short interval, can be used as evidence in court, considering the M -JPEG and MPEG/H series two series of advantages. In some areas of monitoring, in the case of insufficient bandwidth, it is a good choice to retain evidence after an accident.

Alarm pretrigger video function

On the market a variety of network video server in the video are fairly perfect on the function, such as real-time video,timing, video, videoalarm, canbe divided into the mobile video trigger, manual alarm video trigger video, external sensors (such as infrared detector) trigger video, etc. There are a few manufacturers of network video server has alarm trigger video function, can save the alarm trigger a few seconds to tens of seconds before image signal, a function for the user after the alarm event tracking judgment has a special meaning.

Support local storage

At present, with the development of video server, the

application in many places require video server has the function of the local storage, ensure that under the condition of the network is not smooth, and insufficient bandwidth, save some local alarm video, and provides some necessary evidence after the accident.

9, POE function

At present, the video servers are widely used in the development of "ping an city" and "global eyes". , because the monitoring network, decentralizing the distance is far away, some may take electricity is very difficult, if the network video serverwith POE function, so can save the wiring and take the trouble of electricity, but also can save electricity.

10, system integration

The application of a single video server is only a primary application, and its real function is a strong system integration capability.

The soul of the video server is the system integration of the software, and in the absence of standards, more is the manufacturer' s own big system.

The level and scale of system integration is constrained by the software' s ability to undertake and the structure of the hardware. Sometimes the video server delivers software, which can be used in small systems, but not in large scale applications. So in large-scale applications, we need to think about the number of ways in which software can be borne, and

distributed solutions. That is consider to choose a certain brand of hardware products at the same time, also want to consider the other' s software can solve the actual demand of system, or any third party in the development of similar software, because large system software solving the manufacturer request is higher, and more can guarantee the follow-up service. So, when you buy the video server, emphasize the hardware while not ignoring the software.

Voice to speech function

When it is unattended, the best application to remote control,of course there is alsoneed to choose aon thebandwidth control,audio and video synchronization processing ability have a certain level of products have a guarantee. Voice to speak, can realize the communication with the field without obstruction.At present, many products on the market have voice intercom interface Settings, at the time of purchase products, please test the function inthe network, if there is adelaytestvoice.ADSL automatic dialing function

The regular ADSL broadband application must be powered by a computer connected to ADSLModem. However, if the ADSL for remote monitoring access purposes only, so for a simple ADSL dial-up function in each monitoring front-end configuration of a computer, there is no doubt that caused the user equipment resources enormous waste. In this case, the ADSL automatic dialing capability will directly affect the user' s investment budget.

13, warranty issues

The warranty problem is one of the most important issues for engineers. As engineers face the end users, the unsatisfactory warranty service will directly affect the reputation of the engineers. Accordingly, can choose the famous brand, because small brands tend to price is not reasonable and the subsequent lack of technical support ability, and even some products by entering the market. The average manufacturer has a one-year free warranty for the product.