FUNCTIONAL CODING OF VIDEO USING A SHAPE-ADAPTIVE DCT ALGORITHM AND AN OBJECT-BASED MOTION PREDICTION TOOLBOX

This paper presents an object-based layered video coding scheme which achieves very high compression efficiency along with the provision for advanced content-based functionalities, e.g., content-based scalabili ty or content-based access and manipulation of video data. In a first step, a video sequence is segmented into several arbitrarily shaped '' object layers.'' To achieve the desired content-based functionalities, a baseline shape-adaptive discrete cosine transform (DCT) coding algo rithm is introduced which can be seen as an extension of conventional block-based DCT coding schemes (e.g., H.261, H.263, MPEG-1, or MPEG-2) toward coding of arbitrarily shaped image content, In order to increa se compression efficiency, the baseline object-based layered approach can be extended with an object-based motion prediction toolbox. Using this toolbox, the coding scheme can potentially select specific predic tion techniques for every object layer to be coded. To illustrate the concept, an extension of the baseline shape-adaptive DCT algorithm wit h a technique for global background motion estimation and compensation is described which significantly improves the compression efficiency of suitable video sequences compared to standard MPEG coding schemes.