Based On Arm Linux Embedded Streaming Media Player

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 purpose of this thesis is to build streaming media player based on ARM920T.Firstly, this paper analyzes the structure of streaming media playing system. As the aspect of processor, we choose ARM as hardware platform and Linux as the operation system. In respect of real-time transmission protocol, RTP/RTCP and RTSP are chosen. Through simulation results, MPEG-4 and MP3 have been chosen as multimedia standards that the system supports recently, because of their high compression rate and low computational complexity relatively.Secondly, the embedded LINUX is built, and the integrated architecture of streaming media playing system is designed and realized. Based on requirement of OS, we build an embedded LINUX OS for ARM. Based on practical requirement of streaming media player, this paper divides the whole system into five tasks, and realizes all these tasks using five classes and some libraries' APIs. Based on character of multi-media and multi-task, we analyze inter-media synchronization mechanism and inter-thread synchronization mechanism, and solve such synchronous problems. Taking further multimedia compression standards into account, this paper gives a uniform interface for all decoders.Thirdly, we divide all optimization methods into system level, algorithm level and architecture level. For system level ones, we use a method called SCGM (Scene Cache Graph Management). As the aspect of algorithm level ones, we propose a De-blocking Filter based on relationship between blocks, which has lower computational complexity comparing with recent algorithms by simulation results. For architecture level ones, this paper introduces three kinds of optimization methods, which called operation optimization, instruction optimization and pipeline optimization. Simulation results show that, after synthesizing all mentioned methods, the operating frequency for MPEG-4 video decoder is decreased by more than percent 30 comparing with decoder which has been optimized already, and the operating frequency for MP3 audio decoder is decreased by more then percent 40 comparing with LIBMAD before optimization, which has computational advantage.Fourthly, this paper introduces platforms and tools involved in developing the system and gives simulation result.Finally, conclusions of this paper and suggestions for future research are given.