MPEG-2/MPEG-4实时转换Ⅰ帧的快速补偿算法  

A Quick Compensation Method for Ⅰ Frame in MPEG-2 to MPEG-4 Real-Time Transcoding

作　　者：覃团发[1] 唐振华[1] 

机构地区：[1]广西大学计算机与电子信息学院,南宁530004

出　　处：《北京邮电大学学报》2008年第1期116-119,共4页Journal of Beijing University of Posts and Telecommunications

基　　金：广西高校人才小高地建设创新团队计划项目(桂教人[2007]71号);广西科学研究与技术开发计划项目(桂科攻0330010-1)

摘　　要：基于离散余弦变换(DCT)域的MPEG-2到MPEG-4实时转码中,MPEG-2的帧内编码帧(I帧)进行部分解码后所得到的DCT数据不能直接在MPEG-4重量化中使用,提出了一种基于DCT域的Ⅰ帧快速补偿算法.该算法避免了重新进行DCT变换和逆变换,每个宏块节省6次DCT变换和6次逆DCT变换的时间.实验结果表明,与采用像素域补偿算法进行Ⅰ帧转码相比,采用快速补偿算法节省了65.05%的时间,并且转码后Ⅰ帧的峰值信噪比(PSNR)值偏差不超过0.001 dB.The real-time transcoding from MPEG-2 to MPEG-4, the discrete cosine transform （DCT） domain data of intra frame（I-frame） decoded in part by MPEG-2 decoder could not be directly used in re-uantization of MPEG-4. A quick compensation method based on DCT domain is proposed, in which the calculation time of six DCTs and six inverse DCTs are saved in each macroblock for implementing DCT and inverse DCT are not needed. Experimental results show that the transcoding time for I frame is saved by 65.05 % and the peak signal-to-noise ratio （PSNR） error is in 0.001 dB compared with the pixel domain compensation method.

关 键 词：MPEG-2 MPEG-4 码流转换 离散余弦变换域 重量化 

分 类 号：TN919.81[电子电信—通信与信息系统]