SHAPE-ADAPTIVE DCT WITH BLOCK-BASED DC SEPARATION AND DELTA-DC CORRECTION

This paper refers to a shape-adaptive DCT algorithm (SA-DCT) originall y proposed by Sikora and Makai in 1995, The SA-DCT has been developed in the framework of the ongoing MPEG-4 standardization phase of ISO/IE C, and has recently been included in the video verification model of M PEG-4. In this context, the focus of the present paper is to emphasize a systematic performance limitation of conventional SA-DCT, and to pr opose an extended version (Delta DC-SA-DCT) which avoids this restrict ion in general. This modification considerably improves the efficiency of SA-DCT, and can easily be implemented in existing SA-DCT tools.