Multiplexing of luminance and chrominance in NTSC compatible extended definition systems based on subsampling

Methods are presented for luminance-chrominance multiplexing in an NTSC (National Television System Committee) compatible extended-definition transmission scheme based on subsampling. A one-dimensional multiplexing scheme has been illustrated with a 4:1 interlaced sampling structure based on HD-MAC. This one-dimensional multiplexing scheme can also be used with the Triscan 6:1 interlaced sampling structure in a straightforward way. A two-dimensional multiplexing scheme has also been illustrated, this time using a modified Triscan sampling structure. These techniques allow methods similar to those proposed in Europe for HDTV (high-definition television) broadcasting to be used with the NTSC system. Then, all the techniques which have been developed for compatible HD-MAC to improve the quality of the compatible picture and to improve motion rendition in the HD picture can be brought to bear on this scheme. These include preprocessing and postprocessing to reduce flicker in the compatible image and motion-compensated processing for improved interpolation and moving areas in the HD picture