Abbreviation for Absolute Time. Absolute Time is the same concept as Absolute Time Code as it has been used on digital tape systems. A-Time seems to be more associated with discs, but in as much as it’s basically the same thing also applies to tape. Essentially it is the measure of time elapsed from the beginning of the tape or disc, normally measured in hours, minutes, seconds, and frames. This is as distinct from other timing references such as SMPTE, track time, remaining time, etc.