Abstract
The present invention is a transcoder and method for low-complexity DCT-domain video transcoding. The method of the present invention is to find a ni of anchor block Bi, which is neighboring the target block, herein i=1 to 4 and the ni is the smallest can satisfied the energy ratio energy(ni)/energy(8). Then according to ni to calculate n that is used to compute lowest-frequency coefficients matrix of the DCT block. Replace the coefficients with zero to each anchor DCT block excluding scope ni x ni, then combine each the anchor DCT block. The lowest-frequency DCT block is generated by replacing the part of coefficients with zero excluding scope n x n of the combined block.