MPEG-4 to H.264 Transcoding using Macroblock Statistics

In this paper, a temporal resolution reduction transcoding method that transforms an MPEG-4 video bitstream into an H.264 video bitstream is proposed. The block mode statistics and motion vectors in the MPEG-4 bitstream are utilized in the H.264 encoder for block mode conversion and motion vector interpolation methods. The proposed motion vector interpolation methods are developed not to perform brute-force motion estimation again in the H.264. In the experimental results, the proposed methods achieve 3~4 times improvement in computational complexity compared to the cascade pixel-domain transcoding, while the PSNR (peak signal to noise ratio) is degraded with 0.2~0.9dB depending on the bitrates