Very low bit rate video coding for visual communications

This paper reviews the developments in very low bit rate coding of video for visual communication, with emphasis on the transmission of facial images. In this context, model-based coding (MBC) has received considerable attention, and has shown to be a promising approach for coding of video below 64 kb/s. A survey of emerging approaches with respect to different object models, ranging from regional representation of images to 3D wireframe models, is presented. Important issues such as image analysis, parameter coding, and image synthesis are outlined, and a discussion of current problems is given.