Wireless Network Environment Video Compression And Transmission Study

This article is based on the module of video compressing and wireless network transmission of our mobile robot on land ,it contains two parts:robot part and remote control part. Our robot works out of the vision of the operator, so,operator can only do operations using the video data that the robot sends to the remote control .But the bandwith of the wireless network is so limited and the quality of the channel is not so stabilization that we must do some research on the video encoding and network transmission to work out some methods to make the robot's integrity video data reach to the remote control on time and correctly .We will focus on the optimizations of the video encoding and the network transmission,and give the designs of our system at last.At the part of the video compression ,after comparing with some standards on video,we use M-JPEG as our video encoding standard, then we give the process of encoding and decoding of our system, because the M-JPEG does not use the inter mode,so in order to raise the compress ratio,we add the part of motion estimate mechanics to it. We make some improves on the DS arithmetic, by using the technology of forecasting of the starting points ,stopping ahead of schedule and the automatic detecting of the stand block, we improve the veracity and reduce the complication;By classifying the motion vectors,our method is suitable for the video sequences that have large changes.The experiments also show that it works well on our system.At the part of video transmission over wireless network, In order to make the part of decompression work well,we work on some technology just like error conceal, error control and velocity control basing on the protocol of RTP/RTCP, we analyze these methods and use a transmission strategy based on the encoding part, this method can make the velocity of video accommodate with the change of the network ,and reduce the congestion. To solve the problem of packet lost and delay, we also use a buffer control strategy.At last ,in order to deal with the two problems of displaying of the real video and the synchronization of video data and audio data,we give our methods.