Implementation And Rate Of The Wireless Video Communication System Is Optimized

In recent years, wireless communications have experienced unequalled rapid growth. As one of the most important future communication operations, video communication has been attached importance to. The incoming 3G could not only support the existing mobile operations, but also broad band video operations high quality voice packet data transmission and real time video communication. 3G starts a new era of the combination of wireless communication, Internet and video.Lots of information taken by video signals could not be expressed by other ones, for example, text, voice or still image etc. Wireless communications break away from wire fetter and become a important way for free transmission. Because of huge data quantum and high demand of channel bit error rate for video transmission , and fallibility, time variability and limited band of wires channel, wireless video system is faced with lots of problems. H.263+ is one of the mature standards to deal with high compress rate and strong channel error correction ability, which could be perfectly used in wireless video communication areas.This article discusses the modified frame rate control algorithm based on TMN11 and the modified macroblock-layer rate control algorithm. In packet based wireless video communications, when best band distribution, not only source distortion should be considered, but also channel distortion caused by channel errors. The existing macroblock-layer rate control schemes calculates quantization parameters of all macroblocks(MB)in a frame in a raster scan order, and then encodes the MBs in the same order. Actually, the quantization distortion is heavily dependent upon the coding order of MBs. We modify the encoding order of MBs to favor the more complex MBs.The article also present a new kind of wireless video communication system based on WinCE platform. It is based on packet exchange and H.263+ standards. The client is also modified to satisfy the special traits of PDA. Users could incept real time video stream with PDA through GPRS anytime and anywhere , which validate the possibility of video transmission under the third mobile communication systems.