In this paper a novel MPEG-2 transcoder based on DCT domain is proposed. After analyzing the differences between MPEG-2 MP@ML and 4∶2∶2 Profile as well as the properties of discrete cosine transform and some spatial domain filters

the upsampling and linear filter algorithm in DCT domain is derived. The new transcoder has low buffer requirement and results in low delay. Compared with common decoder-encoder cascade methods

the current algorithm can reduce the computation and hardware complexity dramatically due to its omission on DCT(IDCT)

ME(motion estimation) and MC(motion compensation) procedures

which are very time consuming. The simulation results demonstrate

the new approach only suffers slighter quality degradation than the pixel domain method on basis of the conventional decode/re-encode schema

and it is more appropriate to be used in real time environment.