MB Energy Trend-Based Intra Prediction Algorithm for MPEG-2 to H.264/AVC Transcoding

In this paper, we proposed a fast Intra prediction method for MPEG-2 to H.264/AVC transcoding. To reduce the computational complexity, we utilized the information of DCT coefficients in MPEG-2 decoder to measure the Intra macroblock (MB) energy trend. Base on the relationship between the energy trend and the intra prediction direction, we can pre-determine the Intra prediction for both luminance (luma) and chrominance (chroma) components. The numbers of the Intra prediction candidates of luma Intra16x16 and chroma Intra8x8 can be reduced from original four to one or two, and the numbers of prediction candidates of luma Intra 4x4 can be reduced from nine to four. With our proposed algorithm, the computational complexity of Intra prediction for MPEG-2 to H.264/AVC transcoding can be reduced about 60% compared with the conventional cascaded transcoding method at the negligible quality loss.