Improvements in DCT based video coding

We report on recent advances in traditional DCT based video coding at low bitrates. These improvements allow either an increase in coding efficiency or an increase in other functionalities. Our investigation is conductedwithin the framework of the ongoing work towards the MPEG-4 video standard. The ISO Moving Picture Experts Group (MPEG) is currently developing this standard after having completed the MPEG-1 and the MPEG-2 standards. The MPEG-4 video standard is addressing a number of content based as well as traditional functionalities. The development process consists of iterative refinement of the Verification Model (which describes the coding method) via a set of well defined core experiments. Our first experiment is on improved coding efficiency of Intra and uses DC and AC predictions and optimized scanning of DCT coefficients followed by a separate optimized variable length code table. Our second experiment is the study of bidirectional coding to allow additional functionality such as temporal scalability at low bit-rates. We present results of these experiments and summarize our findings.