Direct splitting and merging of 2-D DCT in the DCT domain

An efficient method for splitting an 2-D DCT block into four , two (or ) 2-D DCT blocks is presented in this paper. The reverse direction (the “merge” case) also can be realized by inverse transposing the given matrix operations in the “split” case. The computational complexity of the proposed methods is lower than that of the direct approach and other known efficient converting approaches. Due to its efficiency, the proposed DCT splitter/merger will play an important role in realizing the transcoding between the latest video coding standard, AVC/H.264, and the older ones, such as MPEG-1, MPEG-2, and MPEG-4 part 2. [Copyright &y& Elsevier]