Research And Design Of Embedded Streaming Media Video Player System Over H.264

With the development of communication technology,data compression technology and processor technology,the realization of multimedia application such as Video-phone,Video on Demand and Real-time Video Conference using portable devices has been one of the most important fields in both industry and research.The efficient and practical multimedia terminal that was based on embedded technology,digital image technology and streaming media technology has become the main direction in embedded areas.So the video research of transmission,decoder and play that based on the embedded streaming media technique was more urgent,and it has theoretical and practical significance.Through in-depth studying in embedded,video compression and stream-media technology,the design scheme of H.264 video player system based on embedded Linux was put forward.The charancteristic and the superiority of the ARM architecture processor are briefly discussed in hardware.In soft-ware,first things to do is forming an entire embedded Linux system platform,including compililg cross-developing tool chain for ARM based on "CROSSTOOL";transplanting the "blob" after analyzing bootloader's startup process; replanting Linux kernel to PXA255;introducing the structure of Linux root file system and creating Linux root file system.H.264 has two characteristic,"Network Friendliness" and high coding efficiencies, which make the complexity of the H.264 codec several times higher than that of existing standards.Accordingly,the software-based real-time video codec demands faster-speed algorithms.At the same time,it needs more strategy to make use of the new specific "Network Friendliness" to enhance the efficiencies of the data transmission and errors correction ability.If want the software-based real-time video decoding become true,we should solve these problems,such as,implementing a new style of streaming networking stack and enhanceing the decoding efficient.Based on the analysis of internal structure of the ARM processor and H.264 decoding module,effective optimization is made at all levels of algorithm,structures and assembly compilation,which improve the system performance.Performance improvement obtained by optimization is about 6.1%,and the ability of the optimized system to decode H.264/AVC bitstream of 242×192 and 25f/s is higher than before by about 100kbit/s.The dissertation introduced the content of the H.264/AVC's "Network Friendliness" technology,and then implements a streaming stack to follow the standard.The stack has the ability to add new module to apply the latest standard for transmission new type media data. The implement of H.264 standard consists of the Parameter Set concept,NAL and packaging. All modules of the stack will be introduced in the dissertation.Finally,the article gives the test platform,designs the test methods of video player system on the embedded Linux system platform,and tests every party of this system.The test result proves that player can play the H.264 movie real-time,the subjective video quality is "acceptable" in this hardware and software environment.At the same time,the play system has been enhanced its performance as the H.264 implementation on it.The goal has been reached.