Research And Implementation Of An Embedded Streaming Media Client

With the development of wide-band network technology and multimedia compression technology, the requirement of video on demand with portabel device has become the people's urgent needs. An embedded streaming media player of this kind which is based on the ARM9 platform and embedded Linux system has been implemented in this thesis. In detail, ARM9TDMI (400MHz) and Embedded Linux kernel are used as base platform, RTP/RTSP protocol suite are used as streaming media transfer protocols and H.264, MPEG4, MP3 and etc are used as multimedia coding format.First, the Embedded Linux development platform is constructed, and the embedded streaming media player is developed on this platform. According to the client's functional requirements, the player tasks are divided into four functional modules: multimedia data receiver module, multimedia decoding module, audio and video synchronization module and user interface module. Two Linux threads are used to complete the work of all modules to achieve multimedia data reception, decoding, synchronization and output.Secondly, based on the analysis of internal structure of the ARM processor and H.264/AVC 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 abilily of the optimized system to decode H.264/AVC bitstream of 242x192,25f/s is higher than before by about 100kbit/s.In addition, the H.264/AVC Video Coding Standard is studied in-depth. Based one the analysis of performance of the standard deblocking loopfilter, a Corner Based 2D Adaptive Deblocking Filter(CB-2D-ADF) is present. The proposed algorithm is built on efficient two-dimensional filter structure which can reduce a lot of redundant operations. As a simulation result, more than 50% of computational complexity is cut down compared with the standard algorithm.