Anisotropic 3-D wavelet packet bases for video coding

Video coding algorithms based on 3-D wavelet transforms exist which have a competitive rate-distortion performance and are very fast because motion compensation is not needed. The compression efficiency of these algorithms can be increased by the use of more general wavelet packet transforms. Anisotropic wavelet packets are an even more generalized type of wavelet transform, where multidimensional wavelets do not necessarily have equal dilations in each dimension. This property is advantageous especially for 3-D video coding because video data has different characteristics in the time and spatial dimensions. This paper develops methods to adapt the SMAWZ codec to anisotropic 3-D wavelet packet bases and investigates algorithm complexity and the resulting rate-distortion performance. It can be shown that there exists a fixed anisotropic wavelet packet basis that is able to outperform MPEG-4 by up to 4dB especially for video sequences with low motion.