A multiscale video representation using wavelet decomposition and variable-block-size multiresolution motion estimation (MRME) is presented. The multiresolution/multifrequency nature of the discrete wavelet transform makes it an ideal tool for representing video sources with different resolutions and scan formats. The proposed variable-block-size MRME scheme utilizes motion correlation among different scaled subbands and adapts to their importance at different layers. The algorithm is well suited for interframe HDTV coding applications and facilitates conversions and interactions between different video coding standards. Four scenarios for the proposed motion-compensated coding schemes are compared. A pel-recursive motion estimation scheme is implemented in a multiresolution form. The proposed approach appears suitable for the broadcast environment where various standards may coexist simultaneously.>

The statistical characteristics of full-motion video sources using motion-adaptive variable-bit-rate coding techniques is studied. Analytical models are developed to describe the behavior of the coded video signals based on the encoder structure. The video-compression algorithm used is in compliance with the general MPEG syntax and bit-stream definition. Statistical characteristics associated with each block type and their aggregate are presented. A composite model to represent the number of bits per field for the encoded video traffic that comprises multiple autoregressive models for the number of blocks per field and the number of bits in each coded block is derived. The statistics measured from a sample video sequence are compared to those obtained by the model and it is observed that the model captures the coded video behavior for each block type and their combination reasonably well. This model can be used to further study the cell-generation process of full-motion video codecs and the aggregation of such video sources at the statistical multiplexers.>

A variable-block-size multiresolution motion compensation (MRMC) scheme in which the size of a block is adapted to its level in the wavelet pyramid is proposed. This scheme not only considerably reduces the searching and matching time but also provides a meaningful characterization of the intrinsic motion structure. The variable-block-size approach also avoids the drawback of the constant-size MRMC in describing small object motion activities. After wavelet decomposition, each scaled subframe tends to have different statistical properties. An adaptive truncation process is implemented, and a bit allocation scheme similar to that in transform coding is examined. Four variations of the proposed motion-compensated wavelet video compression system are identified, and it is shown that the coding approach has a superior performance in terms of the peak-to-peak signal-to-noise ratio as well as the subjective quality.>