Compatible HDTV/TV hierarchical scheme for secondary distribution of TV and HDTV signals

摘要

This paper describes a procedure for coding video in the HDTV Interlaced format (HDI) at rates of 34 Mbit/s while satisfying constraints of an embedded specified constant bit rate stream, compatible to an Interlaced Enhanced Definition TV signal (EDI). The term compatibility is used here to imply both (a) resolution compatibility and (b) that a decoder conforming to a specific syntax, should be able to decode an easily extractable stream from the information intended for a higher quality decoder, a feature that is sometimes referred as backward compatibility. Resolution compatibility, while solved easily when dealing with progressively scanned signals is more intricate in the case of interlaced signals and requires careful considerations in the design of the procedure useful for generating the lower resolution (or compatible) signal. Instead of performing a temporal filtering which presents the drawback of blurring the contours in motion, the proposed approach consists of addressing these issues in a spatial hierarchical coding scheme, in which special care is given to the choice of filters, in order to obtain a compatible signal with a good tradeoff between vertical and temporal definition, and with an appropriate suppression of aliasing. The hierarchical decomposition is carried out on a field basis and two constrained filter banks are actually designed in order to deal with the phase shift inherent to field processing procedures.