Optimization Of AVS Decoder And Implementation On Mobile Phone Platform

With the fast development of wireless communication and electronics technique, mobile phone has become more and more prevalent with its performance more powerful. As a platform, complex multimedia applications can be supported. Mobile TV, receiving digital TV broadcasting with mobile phone, is viewed as the development trend in 3G network. The international video coding standards, such as MPEG-4 and H.264, both can act as the implementation measures of stream media on mobile platform, but the expensive patent charge limits their generalization in China.AVS is a video coding standard which owns Independent intellectual property rights by our country. With preferable compression ratio and PSNR, it can be the implementation measure of stream media on mobile platform. Research on AVS-P2 decoding standard is performed in this thesis, fast algorithms are designed against some modules of the decoder, and implementation is carried out based on the standard AVS decoder of USC. In-depth optimization aiming at the program structure and the function mode of the original decoder including bit-stream read and decode, look-up table, local variables and data copy is executed, and a high-performance decoding system is obtained. The average time cost of the optimized decoder in decoding one frame is 14ms contrast to 42ms of the original one. Some simplification methods of decoder are designed in order to promote the performance of decoder at the cost of some loss of image quality.XScale processor and Windows Mobile operating system is in extensive application among hi-end mobile phones. Research on the practical application of AVS decoder is carried out focusing on the platform in this subject. Noticeable problems of transplanting the decoder to XScale platform, optimization of AVS decoder on XScale platform, the application of WMMX and video play with DirectDraw are expounded. Test results indicate that, the average time cost of decoding and displaying one frame with QVGA resolution on our development board is 23ms, practical requirement is reached.The main contributions of this thesis are: a high performance AVS decoder is acquired, which performance is higher than any other known systems; Some optimization algorithms and simplification methods of AVS decoder are put forward, implementation and test is given; A practical AVS decoder is realized on the mobile phone platform.