The methods of calculating the DCT coefficients of the matching blocks from the derived DCT coefficients of the blocks in the reference frames under three different prediction modes of MPEG-2 is discussed

based on which a drift-free MPEG-2 transcoder that achieves motion compensation in the frequency domain is proposed.The rate-distortion optimization is applied to the rate control strategy to get the optimal quantization parameter of each frame

with its fast algorithm further simplified on the basis of G-BFOS method.Our approach can lead to the solutions of satisfactory accuracy but only with a fraction of the complexity of the existing algorithms.