Abstract: The ITU-T recommendation H.263 specifies a coded representation that can be used for compressing the moving picture component of audio-visual services at low bit rates.The basic configuration of the video source coding algorithm is based on Recommendation H.261 and is a hybrid of inter-picture prediction to utilize temporal redundancy and transform coding of the remaining signal to reduce spatial redundancy.TM1300 is a media processor for high-performance multimedia applications that deals with high-quality video and audio.TriMedia's DSPCPU family delivers exceptional performance and high-level language programmability for multimedia applications through the use of its VLIW architecture.TriMedia's VLIW architecture combines innovations in compiler and software design with advances in logic design.pSOSystem is a modular,high-performance real-time operating system designed specifically for embedded microprocessors.It provides a complete multitasking environment based on open systems standards.The feasible video codec running on TM1300 is designed according to the characteristic of the hardware structure.It includes real-time video signal sampling,video codec,video playing and so on.The emphatically key technologies and problem of the real-time implementation of H.263 video codec on TM1300 are discussed.The optimization technical is given in detail to the H.263 encoding and decoding algorithms for this hardware and compile system.This paper also describes several optimization ways,such as using custom operation,loop unrolling,disposing variable and function,decision tree grafting,compile and algorithm optimization,and various optimization methods supported by the TriMedia compilation system as well as techniques for exploiting the fine-grain parallelism of the TriMedia architecture.The test results are listed in the end.