Rate control scheme plays an important role in improving and smoothing the decoding video quality. Over the years

rate control techniques have been studied very intensively for various standards and applications

such as video conferencing with H.261 and H.263

storage media with MPEG1 and MPEG2

and the recent video object coding with MPEG4.This paper firstly described the basis of rate control problem. And secondly classic rate control technology in the standard was introduced. Thirdly we summed up the present techniques as three kinds: rate control technique based on DCT video coder

rate control technique based on wavelet video coder and rate allocation of Fine Granular Scalable video coding. Then we generally discussed and compared the three kinds of methods including the core idea and the advantages and disadvantages of every algorithm of each kind of techniques. Finally

the state of art and possible new directions of rate control were stated.