To reduce the data rate for the digital transmission of a high definition television (HDTV) signal different three-dimensional downsampling patterns were investigated with regard to the three-dimensional spectral domain that can be represented. Resulting from these investigations and from computer simulations sampling patterns allowing the transmission of spectral domains which are optimally adapted to the human visual perception are proposed. For the luminance signal a 2:1 downsampling procedure with motion adaptive pre- and post-filtering is presented. The spatial resolution for stationary areas is not reduced in comparison to the interlaced signal. For the chrominance signals a non-adaptive procedure with a reduction factor of 4 is suggested. In contrast to other procedures the spatial resolution for nonmoving parts is uniformly reduced by a factor of 2 in both the horizontal and vertical direction.