The ITU Radiocommunication Assembly considering a) that digital signals defined according to Recommendation ITU-R BT.601 are required to be transmitted through point-to-point transmission links; b) that coding algorithms have been devised and standards established or proposed to enable such transmission to be effected using bit rate reduction techniques; c) that prototype codec equipment using these algorithms is being developed and needs to be assessed; d) that Recommendation ITU-R BT.800 defines the relevant user requirements; e) that bit rate reduction techniques are also being considered for other applications, e.g. recording; f) that the evaluation of such codecs can best be performed on a subjective basis, due to the complex and adaptive natures of the multi-dimensioned impairments introduced by bit rate reduction; g) that subjective testing methods are defined in Recommendations ITU-R BT.500 and ITU-R BT.800; h) that the selection of appropriate test material is a key step in the planning of subjective assessment and that when results are to be correlated between a number of testing sites or groups the same pictures should be used and should be available at the highest level of quality; j) that the availability of digital recording according to Recommendation ITU-R BT.657 enables a consistent level of high quality to be achieved in the compilation of subjective test sequences.