Wavelet and lapped orthogonal transforms with overlapped motion-compensation for multiresolution coding of HDTV

Abstract

To increase the robustness of high density television (HDTV) signal against transmission noise and to eliminate the drift artifacts, a multiresolution coding scheme for HDTV using hierarchical overlapped block motion-compensated (OBMC) discrete wavelet transform and the Lapped Orthogonal Transform (DWT-LOT) is developed. A data loss concealment scheme is required to provide graceful degradation, especially in HDTV broadcast and transmission environments. The effect of drift artifacts is one of the major problems in a classical multiresolution video coding such as frequency scalable coding where different resolutions do not have their own accurate motion information. Our research not only exploits advantages of discrete wavelet transform and hierarchical OBMC to solve the drift problem, but also enhances MPEG scheme, which is applied for the lowest resolution, by replacing the DCT with the LOT, along with OBMC to significantly improve the data loss concealment and mitigate the degradation of picture quality due to transmission noise. Three resolutions at the constant bit rate (CBR) for applications to HDTV, conventional TV, and videophone are aimed at. Data loss concealment, for both intraframes and interframes, is illustrated, the elimination of drift artifacts is demonstrated, and the superiority of the enhanced MPEG scheme over the existing MPEG scheme is shown. Simulation results also show that good subjective and objective quality can be achieved for all three resolutions.