减少码率变换再量化误差的优化方案

阐述了码率变换再量化过程中再量化误差的产生及其实质，给出了应用最小均方误差（MSE）准则减少再量化误差的原理，在码率变换再量化器一端，根据首次量化值在量化区间的概率分布中心决定该量化值的区间，有效地消除了量化区间跨区交叠所引入的再量化误差，给出了减少再量化误差方案的实现步骤。实验和模拟结果均表明：该方案有效地减少了再量化误差，获得了较好的图像质量。

Optimized scheme of reducing re-quantization errors in MPEG transcoding

We precisely expose a problem occurred during re quantization process in MPEG 2 transcoding. Firstly, we expatiate the origin of the problem; then, we systematically propose a scheme which uses MSE rule to reduce the re quantization errors. In the end of this paper, we formulize the differences between traditionally used method and our proposed method. Theories and simulation results show that our proposed scheme efficiently reduces the re quantization errors while results in higher picture quality.