Now that we understand the basic differences between SD and HD video, and particularly the concepts of resolution and aspect ratio, it will be easier to discuss the three HD "modes," 720p, 1080i and 1080p. Sometimes referred to as "flavors," these will be called "modes" in this guide in order to distinguish them from "formats," which will be covered in the following section.
The three video modes are designated by their resolution and scan method. Within these modes only one aspect ratio, 16:9, is possible, though several frame rates are possible.