Technology of wireless video monitoring and system are summed up

From;  Author:Stand originally

The H that ITU-T promulgates. 261 standards, use at picturephone and conference TV. H.263 standard is ITU organization video of rate of a when put forward to satisfy a code to lead the application under 64kb/s small yard reduces encode proposal; Better picture quality is achieved below the case that it can lead in inferior code, because this applies extensively at the domain such as conference of long-range monitoring, TV and picturephone, be in especially video monitoring domain, it can have been in embedded the compression that real time, stability achieves in the system the effect, it is to apply more video to compress algorithm. At present product of most video monitoring supports MPEG-4 and H.263 level.

Regard current and newest video as encode technology H.264, there is very big perspective in the application that how prevents a trade. H.264 standard used high accuracy, much mode to forecast a technology to be used raise compression ratio to flow in order to reduce a code. The need that H.264 standard transmits in the light of the network designed video to code a VCL and network extract layer NAL structure, network abstraction layer is to offer " the network is friendly " interface, make video codes the layer can receive effective application in all sorts of systems thereby. The needed to design accident to eliminate tool that H.264 standard transmits in the light of the network facilitates compress video to be in pile up by accident, in losing a bag to send an environment more, transmit, assured the effectiveness that video transmits thereby. The product of wireless video monitoring that supports H.264 level already also appeared on the market at present.

To can be in when change, bandwidth is finite, video data is transmitted on the wireless channel that the code leads QoS of taller, lack to assure by accident, video codes algorithm must satisfy the following requirement: (1) efficient video compression ratio; (2) sex of taller transmission real time: Delay when shorter transmission, rapidder encode rate; (3) stronger video transmits rash club sex: Get used to transmission channel better by accident bit interference. Accordingly, research makes up decipher mechanism mediumly in application of wireless video monitoring, the key is making up decipher efficiency and interference rejection ability at rising further.

2. Wireless video transmits network link and group net technology

To wireless video monitoring, of wireless network transmission link choose basically depend on user demand and the particular environment that the system works, already threw use wireless video supervisory system to basically those who be based on mobile network is mix at present the two sort that are based on wireless local area network. But asking to phonic video quality not tall application is medium, the wireless data that also can use low end transmits a network.

In the trade of two big operation that uses communication network in Chinese eye reach, chinese UniCom uses the CDMA2000 1x that is based on the location that pile up cent to make type, highest download speed can amount to 153kbit/s, actual measurement showing a network can amount to 100kbit/s left and right sides. Chinese shift uses GPRS technology, be what be based on GSM network to develop and come is new-style exchange data application business in group, bandwidth theory is highest can amount to 171.2kbit/s, chinese shift shows a net to check to also can achieve 35kbit/s left and right sides. Below current network bandwidth, average user can use colour E to transmit video document, many manufacturer also rolled out the video supervisory system that is based on 2.5G shift public network, regard pair of wired networks as the strong complement of supervisory system.
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