MPEG-2 to H.264 video transform-domain downscaling transcoder

In this paper, we proposed a transform-domain MPEG-2 to H.264 intraframe downscaling transcoding algorithm. The proposed algorithm effectively performs 2:1 down sizing from an 8 x 8 discrete cosine transform coefficient matrix into a 4 x 4 integer transform coefficient matrix without involving any spatial-domain process. By exploiting the proposed approach, the complexity of the transcoder is reduced. From the experiment results, we can find that the proposed transform-domain MPEG-2 to H.264 transcoder leads to a similar PSNR compared to that derived from the Cascaded Pixel-Domain Transcoder (CPDT) while the propose method can save 38% and 91% of computation on the numbers of multiplication and addition, respectively.