H.264/AVC to MPEG-2 Video Transcoding Architecture

Video transcoding is assuming an important role in modern video communication systems in order to allow interoperability between different equipment and standards. So far most effort has been spent in transcoding from older standards to the most recent ones. However, as new standards reach higher levels of compression efficiency, the diversity of bitstream formats also increases. In this paper we propose a new transcoding architecture for H.264/AVC (Advanced Video Coding) to MPEG-2 Video. Since both standards are based on the same coding paradigms, interframe block based motion estimation and intraframe transform coding, the proposed architecture explores their similarities in order to achieve an efficient format conversion. The proposed transcoder significantly reduces the computational complexity of the MPEG-2 Video motion estimation based on the information included in the H.264/AVC bitstream. The presented results from our architecture show a significant computation reduction, as much as 30%, with a small objective quality reduction.