Issues in H.264/MPEG-2 video transcoding

The H.264 video coding standard has recently been standardized under the auspices of both the ITU and the ISO video experts groups. This new generation video standard, with its significant bandwidth savings, is expected to replace the use of MPEG-2 video compression in digital video systems. The complete migration to the new video coding algorithm will take several years given the wide scale use of MPEG-2 in the market place today. This creates an important need for transcoding technologies that transcode the widely available MPEG-2 compressed video to H.264 compressed format and vice versa. The high transcoding complexity can be reduced by reusing the information gathered in the video decoding process. However, given the significant differences between the MPEG-2 and the H.264 coding algorithms, transcoding is much more complex compared to MPEG-2 to MPEG-4 transcoding. We give a brief introduction to H.264 and discuss the issues in transcoding and complexity reduction.