Significance of tree structures for zerotree-based wavelet video codecs

In this paper we investigate the significance of tree structures on the performance of zerotree based wavelet video codecs. Since zerotree approach is based on aggregation of insignificant coefficients in trees, therefore design of a tree structure is the key issue for a better performance. We have considered four different tree structures with characteristics varying from a simple to relatively complex and composite tree structures to code the luminance-chrominance components of a video sequence. We observe that in general more complex and longer trees do not necessarily improve the coding efficiency. Further, the simulation results show that by designing an efficient tree structure, depending on the picture content, the performance of the video coder can be improved by up to 2.0 dB.