Object-based Subband/wavelet Video Compression

This chapter presents a subband/wavelet video coder using an object-based spatiotemporal segmentation. The moving objects in a video are extracted by means of a joint motion estimation and segmentation algorithm based on a compound Markov random eld (MRF) model. The two important features of our technique are the temporal linking of the objects, and the guidance of the motion segmentation with spatial color information. This results in spatiotemporal (3-D) objects that are stable in time, and leads to a new motion-compensated temporal updating and contour coding scheme that greatly reduces the bit-rate to transmit the object boundaries. The object interiors can be encoded by either 2-D or 3-D subband/wavelet coding. Simulations at very low bit-rates yield comparable performance in terms of reconstructed PSNR to the H.263 coder. The object-based coder produces visually more pleasing video with less blurriness and is devoid of block artifacts.