DCT domain intra MB mode decision for MPEG-2 to H.264 transcoding

This paper presents a macroblock (MB) mode estimation technique for MPEG-2 to H.264 intra frame video transcoding. This technique can be applied in number of consumer electronic applications such as DVRs and content delivery systems. The DCT coefficients gathered from the MPEG-2 process are used to estimate the MB coding mode. The estimated mode is used to constrain the MB prediction mode computation just to the estimated MB mode. Our approach uses the DCT coefficients obtained during the MPEG-2 decoding stage and classifies an MB as INTRA16times16 or INTRA4times4. The computational cost of the DCT domain operations is negligible but results in substantial savings in the H.264 mode estimation. The results show that the PSNR drop caused by this direct estimation is negligible