视频监控视频监控服务器的特点与选购（Video monitoring server features and selection）

视频监控服务器的特点与选购Video monitoring server features and selection

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 devices are still video servers. 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 server generally includes audio and video collection parts, central processor part, data encoding part, network part and alarm cloud control part. Since the camera outputs the data of the DVS as the analog signal,and the signal transmitted in the network is the digital signal,the audio-audio collection of A/D conversion must be converted into A digital signal. 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. Network protocols such as DHCP, DDNS, UPNP and NFS need to be supported.

Some of the basic features of the current video server are.

1. Small model. 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.Simplicity. 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.

3. Powerful 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 directly access any camera and can also access the monitored image through a central server.

4. Easy to upgrade and extensibility. You can easily add more cameras, and the center 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 802. 11a, b, g communication protocol, while internal contains 3G function module, which can integrate video server and 3G mobile network. This product can be transmitted by cable and wireless network, and users can choose themselves, which fully reflects the features of video server product simplicity. 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.

The camera and DVS are connected by a short transmission line,which eliminates the cost of long laying cables, which fully reflects the characteristics of both economy and good cohesion.Video server shopping guide

1. Picture quality

This is the basic premise of remote monitoring, which is the basic factor to ensure the realization of remote monitoring and unattended. Currently, there are two kinds of quality CIF and D1 choices in the market, which are 352 x 288 and 704 x 576respectively. The DVD quality of D1 is the most ideal,regardless of the other factors, but if you consider the bandwidth issue, the CIF can handle the needs of ordinary occasions.

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.

2. Different image bandwidth requirements

This is one of the important indexes of the overall performance of 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 relativelyunified 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. Internet explorer monitoring function

The routine monitoring and management software for the

implementation of the integrity, the operation of the cumbersome inconvenience, and even specialized training to learn to master. 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. Network environment

When buying a product, the first thing to look for is the product to be used in what place and what is the network environment?Instead of buying blindly. If the network environment is not very good, choose the product with high demand for the network,in the actual application, also has no practical significance.Like a Mercedes, crawling along the dusty mountain road, there is no room for manoeuvre.

5. Latency of remote video transmission

Transmission latency is inevitable for any network video server,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 field signal, and the general bandwidth is not limited, the

product is required to be kept at the microsecond level. That is to say, the video server itself has a negligible latency in the absence of bandwidth constraints, so it' s better to give sufficient bandwidth and test its performance in a local area network.

6. Front-end capturing 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 surveillance, in the case of insufficient bandwidth, it is a good option to retain evidence after an accident.

7. 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.

8. 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, video server has been widely used in the promotion of "pingan city" and "global eye". , 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 lies in a strong system integration capability.

The soul of video server lies in the system integration of software. In the absence of standards, it is more the big system of the manufacturer itself.

The level and scale of system integration is limited by the software' s ability to undertake and the structure of the hardware. Sometimes you can buy video server to send software,

it can be used in a small system, but it can' t adapt to large-scale application. Therefore, in large-scale application, we should consider the number of roads that software can bear, and corresponding 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 a video server, emphasize the hardware while not ignoring the software.

11. 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 site without hindrance.Currently, many products in the market have voice intercom interface. When purchasing products, please check the function on the network to test whether the voice has a delay.

12. ADSL automatic dialing function

Regular ADSL broadband applications must be driven 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 the above situations, whether the

ADSL automatic dialing functionwill directly affect the user' s investment budget.

13. Warranty issues

Warranty problems are one of the most important issues for engineers. As the engineers face the end users directly, the unsatisfactory warranty service will directly affect the reputation of the engineers. Therefore, it is possible to choose well-known brands, because small brands tend to be unreasonable in price and lack of follow-up technical support,and even some products enter the market through stickers. The average manufacturer has a one-year free warranty on the product.