Bandwidth reduction for HDTV transmission-alternatives and subjective results

It is shown that an efficient bandwidth reduction of HDTV (high-definition television) signals can be achieved with separable three-dimensional filters, without compromising motion portrayal. A variety of alternatives for prefiltering at the encoder and postfiltering at the decoder was studied with respect to picture performance and implementation costs. Results are compared on test patterns and related to real HDTV pictures. The basic encoding/decoding scheme of the HDS/NA approach allows for a variety of prefilter and postfilter alternatives to achieve a desired two- or three-dimensional bandwidth reduction. It was shown that prefiltering and postfiltering based on only horizontal and vertical filters gives a good tradeoff between the loss of some diagonal picture detail and the suppression of aliasing artifacts