Joint rate distortion optimal shape and texture coding

Abstract

In this paper, the problem of joint shape and texture coding in video compression is considered. The shape is approximated using polygons or higher order curves. The texture is encoded using the shape adaptive discrete cosine transform (SA-DCT). The solution is optimal in the operational rate distortion sense i.e. given a coding setup, the solution will guarantee the smallest possible total rate for a given distortion for both shape and texture coding or the smallest possible distortion for a given rate. Both a fixed-width and a variable width distortion band for shape coding were considered. The variable width of the distortion band is a function of the texture profile i.e. the width is inversely proportional to the magnitude of the image gradient. We present experimental results using the Kids and Bream sequences.