An apparatus and method of signal processing for rounding digital data, such as digital video data, wherein ten-bit digital data may be rounded to eight-bit digital data. Included is a bit pattern generator for generating at least four bit patterns, each bit pattern having at least two single-bit samples. One fixed bit pattern is selected whereby the value of the low-order two bits of the ten-bit digital data is rounded and added to the high-order eight bits to produce rounded eight-bit data. Since fixed bit patterns are used in the rounding process, the rounding of digital video data, and thus picture quality, is improved. In addition, the adverse generation of an inherent vertical bit pattern can be prevented by re-ordering the single-bit samples into a fixed bit pattern.