Two possible adaptive subsampling strategies for bandwidth compression of an HDTV signal are described and the results of computer-based investigations of their performance are given. The strategies, known as 'slope' coding and 'BASS' (Block Adaptive Sub-Sampling) coding, are examples of 'revolutionary' or non-compatible versions of DATV (Digitally Assisted TeleVision). The results indicate that either of the strategies could be used to achieve a fourfold compression in bandwidth, enabling the transmission of an HDTV signal within a single WARC 77 DBS channel, but that BASS coding is the more promising of the two in terms of output picture quality, particularly when it is used in conjunction with motion compensation. Some practical considerations relating to hardware design are also discussed.