可变码率视频编码的缓存控制策略

Buffer Control Algorithm for Variable Bit Rate Video Coding

基于数字多用视频光盘（ＤＶＤ）视频编码在应用ＭＰＥＧ－２ 可变码率压缩算法时要求一种新的码率控制方法，在美国电信科学学院建立的一套图像质量Ｓ评估的基础上，研究了Ｓ和编码码率的关系．Ｓ较低时，Ｓ与编码码率成正比关系．为实现可变码率编码，在线性增长区，对可变码率的编码算法给出了一套计算公式，使得在一定平均码率下，对一定的图像序列进行可变码率编码，得到相对恒定的Ｓ．

DVD video utilizes MPEG 2 variable bit rate (VBR) compression process, its video encoding algorithm requires a new rate control method for VBR encoding that yields best and constant picture quality. On the basis of most commonly used quality measure developed at Institute for Telecommunication Science in Colorado, the relation between image quality and bit rate was studied. It was found that the image quality increases linearly with the increment of bit rate when image quality is less than 4.5. In order to implement VBR coding, some formulas were given in the linear increment area. At some constant average bit rate, relatively constant image quality can be obtained to an image sequence.