Frame

A whole television picture. A frame has shape, its aspect ratio. Today all new TV frames have a 16:9 aspect ratio. Some motion pictures are presented on TV with a wider aspect ratio, typically with a black border above and below. A frame has a specific resolution and is either using interlaced (I) or progressive (P) scans. Most productions now originate in an HD format of either 1280 x 720P or 1920 x 1080(I or P) pixels. Some still use SD with 701 x 576I or 701 x 480I frames. These two SD standards do not have square pixels, all other DTV frames do. In UHD a frame could have 3840 x 2160 (4K) or 7680 X 4320 (8K) pixels. UHD only uses progressive scans. Interlace makes a relatively low frame rate of 25 or 30 f/s (shown as 50 or 60 fields/s) suitable for portraying motion quite well but, without further processing, stop motion freezes can look poor.

Another property of a frame is its color gamut, as defined in its standard. As TV video standards have progressed, so the associated color gamut has expanded. Some say this is the most striking change from HD to UHD. UHD frames may also have a higher dynamic range (HDR) – again enhancing the look of the pictures. A frame has a specific time. Usually 1/25 or 1/30 of a second. Larger frame formats, especially 4K and 8K, require faster frame rates to reasonably portray smooth movement on a big screen. See ‘Frame rate below’.

See also: Interlace