Fast mode decision algorithm in H.263+/H.264 intra transcoder

Abstract

In this paper, we proposed a fast mode decision algorithm in transform-domain for H.263+ to H.264 intra transcoder. In the transcoder, the residual signals carried by H.263+ bitstreams are threshold controlled to decide whether we should reuse the prediction direction provided by H.263+ or reestimate the prediction direction. Then the DCT coefficients in H.263+ bitstreams are converted to H.264 transform coefficients entirely in the transform-domain. Finally, by using the new prediction mode and direction, the H.264 transform residual coefficients are coded to generate the H.264 bitstream. The simulation results show the performance of the proposed algorithm is close to that of a cascaded pixel-domain transcoder (CPDT) while transcoding computation complexity is significantly lower. © Springer-Verlag Berlin Heidelberg 2006.