Based On The Dm642 Mpeg-4 Encoder

With the development of information society, multi-media technology is getting more and more applications. In the world of multi-media, video coding plays the key role, especially in the areas of image communication, video surveillance, stream media, digital TV. Through image compression, the sampling, storage, processing and transmitting ultra-large data become possible. Among them the effect of motion estimation is important. It effectively reduces the temporal redundancy between successive frames. Then more compacted video data is obtained.With the development of the embedded video application need, Currently, the implementation of video encoder is as follows. Firstly, using dedicated ASIC chip for video coding. Secondly, using special video digital signal processor. The last one is using a universal media DSP, such as DM642, with 600 MHz and 4800 MIPS, designed by TI corporation. These points make the last way more flexible than the other ways as well as high performance.At the beginning of this paper, we will introduce the development history of the video standard, then introduce the key modules of MPEG-4, such as motion estimation, texture encoder. After that, we will put the emphases on the fast motion estimation algorithm including 'Half-Pixel Motion Estimation Based on Linear Prediction' and 'A Fast Two Step Search Algorithm for Half-Pixel ME'. Experimental results show that significant reduction in computation of motion estimation is achieved by using the proposed method, without visible loss in video fidelity and increment in bit rate. At last, we will optimize the MPEG-4 video encoder based on the DM642 platform. Several methods will be used such as changing the flow the code, optimizing the memory system, refine the code style, enhance the level of code parallel. During the project, I obtain some methods and skills in developing a media application based on the DSP platform.