TV formats

HDTV - support for resolutions of 1920×1080 (1080i) and 1280×720 (720p).
ATSC - like HDTV, but supports 1080p video format.
UHDTV - support for the resolution 7680x4320.
DVD9 - 720×576 resolution.

For example,
NTSC - 720×480.
PAL - 720×576.

Letters i and p (720p and 1080i)

i - the video goes at a speed of 50 or 60 half-frames per second (interlaced). This solution allows you to reduce the flow of data in the transmission of video, but there are "artifacts of movement."

p - the video comes at a speed of 24, 25, 30, 60 full frames per second (progressive scan), looks more natural. Disadvantages - a lower speed (less frames per second) or a larger stream for video transmission at 50 and 60 frames per second.