Broadcasting term for the video and audio streams that ultimately go on-air, as well as the hardware that ensures both streams meet broadcast specifications for standard definition, high definition, analog, and digital.
Play to air (PTA) devices are generally located in Master Control, and are the farthest downstream on any feed in a television station. This downstream video is the lowest quality available in the station, since it is has been shuffled through a multitude of processors, keyers, character generators, and switchers. Video and audio near the end of this chain is referred to as "stepped on."