Adaptive scalable video coding using wavelet packets

In this paper a hierarchical spatial scalable wavelet video coder is presented. The scheme employs backward motion compensation, therefore no motion vectors have to be transmitted. The coarser levels of the wavelet decomposition of the current frame are used for motion estimation and motion compensation of the lowpass band of the next finer level. The lowpass band of the coarsest level has to be coded separately, e.g. using DPCM. Here, adaptive wavelet packets are proposed for encoding of the prediction error. The structure of the decomposition tree is found by employing a rate/distortion optimal search. For each predicted subband, the tree information and the coefficients of the wavelet packet bands of the decomposed prediction error are encoded. The drawback of additional forward information for the wavelet packet trees is compensated by the performance gain achieved by coding the wavelet packets subbands. The proposed adaptive scheme reveals an increase of up to 0.8 dB of coded PSNR compared to the non-adaptive scheme.