There are two HD formats which provide one thousand and eighty lines of resolution. The two formats are,

1. 1080i
2. 1080p

The i stands for interlaced and the the p for progressive scan. The 1080i format is capable of displaying content at a resolution of 1920 x 1080. Depending on the country a 1080i television is operating in, it will function at either a 50 Hz or 60Hz frame refresh rate. As of 2010, Sky, and reputedly the BBC and ITV, broadcast their HD content in the 1080i format. The interlaced format builds up an image frame by first displaying the odd numbered resolution lines, and then the even numbered resolution lines. Because the interlaced technology takes two passes to build an image, compared to the progressive scan's one, it is considering the inferior technology.