480p is the shorthand name for a family of video display resolutions. The p stands for progressive scan, i.e. non-interlaced. The 480 denotes a vertical resolution of 480 pixels, usually with a horizontal resolution of 640 pixels and 4:3 aspect ratio (480 × 4⁄3 = 640) or a horizontal resolution of 854 or less (848 should be used for mod16 compatibility) pixels for an approximate 16:9 aspect ratio (480 × 16⁄9 = 853.3). Since a pixel count must be a whole number, in Wide VGA displays it is generally rounded up to 854 to ensure inclusion of the entire image. The frames are displayed progressively as opposed to interlaced. 480p was used for many early Plasma televisions. Standard definition has always been a 4:3 aspect ratio with a pixel resolution of 640 × 480 pixels.
The ATSC digital television standards define 480p with 640×480p (4:3) pixel resolutions, at p24, p30, or p60 frames per second.
Both 480p24 and 480p30 are more common in countries that use or have used the interlaced NTSC system like North America and Japan (these formats are somewhat compatible with that system, when used to broadcast progressive film content).