Fast Interframe Transcoding from H. 264 to MPEG-2

This paper deals with conversion from H.264/AVC (advanced video coding) coded video into the MPEG-2 format. The proposed approach exploits similarities between the coding techniques used in both standards in order to achieve a computationally efficient method for transcoding interframe coded slices. The conversion process is based on adaptation of both coding mode and motion information embedded in the H.264/AVC video stream, such that subsequent MPEG-2 encoding takes full advantage of the higher computational effort spent on the first encoding step. The proposed transcoding scheme significantly reduces the computational complexity needed for MPEG-2 interframe coding by reusing relevant information from the H.264 bitstream. The simulation results show that computational complexity savings up to 60%, with a marginal objective quality cost, can be achieved in comparison with a cascaded decoder-encoder.