Abstract: To eliminate the `drift' artifacts, to increase the robustness of HDTV signal against transmission noise, and to accrue to users of existing MPEG applications the benefits of forward/backward compatibility, in this paper, we present a scalable coding scheme for HDTV using hierarchical overlapped block motion-compensated (OBMC) wavelet transform and the Lapped Orthogonal Transform (LOT). The effect of `drift' artifacts is one of the major problems in a classical scalable video coding such as frequency scalable coding where different resolutions do not have their own accurate motion information. A data loss concealment scheme is required to provide graceful degradation, especially in HDTV broadcast and transmission environments. Our research not only exploits advantages of discrete wavelet transform (DWT) and hierarchical OBMC to solve the `drift' problem, but also enhances MPEG standard by replacing the DCT with the LOT to improve the data loss concealment and mitigate the degradation of picture quality due to transmission noise. Furthermore, this enhanced MPEG scheme, which is applied to the lowest subband, also provides the compatibility to the widely-adopted MPEG standard and its existing applications. Three resolutions for applications of HDTV, conventional TV, and videophone, are aimed. Optimal bit allocation is developed for each resolution. Simulation results show that very good subjective and objective quality can be achieved for all the three resolutions. The elimination of `drift' artifacts is observed and performances of LOT and DCT incorporating with the DWT are compared in terms of error concealment and coding gain.!24
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