An efficient transcoding from MPEG-2 to MPEG-1

This paper proposes a fast and efficient transcoding algorithm from MPEG-2 video to MPEG-1 video where spatial resolution reduction is involved. We use quantization parameters along with motion information of the incoming MPEG-2 video bitstream to estimate the motion vectors for MPEG-1 transcoding without any additional motion estimation process. Since such information can be directly extracted from the original MPEG-2 video bitstream, very fast transcoding can be achieved. In addition, since the proposed method is not restricted to a specific coding structure, it can be applied to various types of GOP structures. The experimental results show that the proposed method can provide approximate motion vectors to that of full range motion estimation. therefore transcoding efficiency can be increased and picture quality is enhanced when compared with the conventional fast transcoding methods.