The ITU Radiocommunication Assembly considering a) that a number of administrations and organizations throughout the world are currently using and/or evaluating high-definition television systems, and that in many parts of the world HDTV broadcasting is likely to become the primary medium of the next century; b) that subjective assessments are a vital element in HDTV system design and selection; c) that Recommendation ITU-R BT.500 outlines general subjective assessment methods, many of the methodological details of which are also appropriate in the context of HDTV; d) that Recommendation ITU-R BT.500 has been modified to provide only general information on methodology for the subjective assessment of the quality of television pictures.