SOURCE-CODING OF WAVELET-TRANSFORMED DIGITAL HDTV FOR RECORDING APPLICATIONS

A novel intraframe source-coding algorithm suitable for the recording of digital high-definition television signals is presented. A multilay ered, hierarchical description of the source signal is obtained by mea ns of a quad-tree, halfband wavelet transform. This transform decompos es the input signal into a collection of spectrally nonoverlapping sub -bands. These are used to influence the allocation of the available co ding resources to the various layers, so that the integrity of visuall y significant features can be preserved. Individual sub-bands are quan tised and entropy coded by using a predictive arithmetic coding techni que. The algorithm is tuned to achieve bit-rate reduction ratios in th e range 8:1 - 4:1 which is most useful for recording applications. Res ults obtained from simulating the coding algorithm show noticeable imp rovement over the current state-of-the-art international standard algo rithm for still picture encoding, both in terms of subjective quality and of measured mean-square error.