The three HDTV formats are 720p, 1080i and 1080p, with the latter being the highest resolution. See HDTV and DTV for more details.
"HDTV formats." YourDictionary, n.d. Web. 15 June 2018. <http://www.yourdictionary.com/hdtv-formats>.
HDTV formats. (n.d.). Retrieved June 15th, 2018, from http://www.yourdictionary.com/hdtv-formats