4K resolution
The term "2160p" could be applied to any format with a height of 2160 pixels, but it is most commonly used in reference to the 4K UHDTV resolution of 38402160 due to its association with the well-known 720p and 1080p HDTV formats. Although 38402160 is both a 4K resolution and a 2160p resolution, these terms cannot always be used interchangeably since not all 4K resolutions are 2160 pixels tall, and not all 2160p resolutions are ≈4000 pixels wide. However, some companies have begun using the term "4K" to describe devices with support for a 2160p resolution, even if it is not close to 4000 pixels wide. For example, many "4K" dash cams only support a resolution of 28802160 (4∶3); although this is a 2160p resolution, it is not a 4K resolution. Samsung also released a 51202160 (64∶27) TV, but marketed it as a "4K" TV despite its 5K-class resolution.
Digital cinema
The theoretical resolution of 35 mm film is greater than that of 2K digital cinema. 2K resolution (2048×1080) is also only slightly greater than that of consumer based 1080p HD (1920x1080). However, since digital post-production techniques became the standard in the early 2000s, the majority of movies, whether photographed digitally or on 35 mm film, have been mastered and edited at the 2K resolution. Moreover, 4K post production is becoming more common (Dec 2013). As projectors are replaced with 4K models the difference in resolution between digital and 35 mm film is somewhat reduced. Digital cinema servers utilize far greater bandwidth over domestic "HD", allowing for a difference in quality (e.g., Blu-ray colour encoding 4:2:0 48Mbit/s MAX datarate, DCI D-Cinema 4:4:4 250Mbit/s 2D/3D, 500Mbit/s HFR3D). Each pixel has greater detail per frame.