The 1920x1080 "progressive scan" HDTV format. Also called "Full HD" or "True HD," 1080p is the highest resolution found on most digital TV sets. However, starting in 2012, 4K TVs emerged with 2160p resolution (see 4K TV). On TV screens smaller than 40", it may be difficult to distinguish the difference between 1080p and 720p, the lowest HDTV resolution. 1080p Out - Not 1080p In Some of the first HDTV sets did not accept incoming 1080p signals from Blu-ray players and other sources. They supported 1080i and lower resolutions, which they upconverted to 1080p for the screen. See progressive scan, HDTV, DTV, HD formats, 1080i and 720p.