Error Control For Wireless Transmission And The Decoder Implementation With ARM Based On The H.264

The advent of information society, as well as the emergence of IP technology, are profoundly changing the face of telecommunications networks and the future direction of technology development. Wireless communication technologies provide strong pledge for the realization of the development of digital communities. Video communication is the kernel of multimedia operation. The transmission of video content over wireless networks poses big technical challenge duo to the specific characteristics of wireless channel such as bad environment, so it becomes a hotspot for the research.For the wireless channels, the available bandwidth is limited. Due to the multipath effect, multipath delay, multipath fading and some other reasons , the mobile communication has the characteristics that its bandwidth is undulate and high bit error rate, so some continuous and gusty error of transmission usually appears. The reliability of the transmission decrease because of the available bandwidth and the transmission rate are time-variant.Video display needs well timeliness, this requires the sufficient bandwidth,guaranteed time lag and the bit error rate. In order to replay the video , we need at least 28 Kbits bandwidth. Video transmission is very sensitive to the time lag. But mobile network couldn't provide credible services.Based on the challenge of the wireless video communication, this paper dose some research on the H.264 , especially on how to well control error diffuseness and improve coding efficiency as well as how to realize the H.264 decoding on ARM platform.In wireless communication system, there are many great challenges in transforming reliable video signals. So, how to effectively control bits error becomes urgent and significant. In this method is proposed to control bits error in low bit rate wireless transmission system. This method can use less overhead bits to control bits error of the interesting areas to improve the quality of the area of the image, and can automatically adjust the number of MB( Macroblock ) to make fully use of the limited bits rate according to the location, the size , and the shape of the interesting area.In order to effective balance contradiction between coding efficiency and the anti-error code ability, the author proposed one auto-adapted FMO code method; could auto_adapted and choice FMO encoding pattern needed according to the image complexity.The simulation result indicated that this FMO encoding method is completely feasible, especially the effect is more obvious when movement complexity frequent change.It can apply in the bad wireless channel environment.Based on the research on the hardware of the PXA270 and the X264, we basically realized decoding process on ARM platform. Do some environment setting on PXA270,customize WinCE Operation System,compile,produce SDK for application exploitation and download kernel into target ship. make use of exploit tool EVC ,make application program realtime and debug on line, finally realized realtime decoding for no error H.264 code.