H.264 to MPEG-4 Transcoding Using Block Type Information

In this paper, we propose a heterogeneous transcoding method of converting an H.264 video bitstream into an MPEG-4 video bitstream. When the H.264 video bitstream is transformed into the MPEG-4 video bitstream, the conversions between the H.264 block types and the MPEG-4 block types are performed by minimizing the distortion, and 4times4 block-based motion vector mapping is performed. The proposed transcoder runs 5.2 times faster than the cascaded transcoding method, while maintaining the similar PSNR (peak-signal-to-noise ratio).