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 scalability 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 algorithm 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 increase 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 prediction techniques for every object layer to be coded. To illustrate the concept, an extension of the baseline shape-adaptive DCT algorithm with 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.