4K resolution
4K resolution is a horizontal display resolution of approximately 4,000 pixels. For digital cinematography, it is ; for digital television, it is , typically with a 16:9 aspect ratio.
The 4K television market share increased as prices fell dramatically throughout 2013 and 2014.
4K standards and terminology
The term "4K" is generic and refers to any resolution with a horizontal pixel count of approximately 4,000. Several different 4K resolutions have been standardized by various organizations.The terms "4K" and "Ultra HD" are used more widely in marketing than "2160p". While typically referring to motion pictures, some digital camera vendors have used the term "4K photo" for still photographs, making it appear like an especially high resolution even though 3840×2160 pixels equal approximately 8.3 megapixels, which is not considered to be especially high for still photographs.
DCI Digital Cinema System Specification
In 2005, Digital Cinema Initiatives, a prominent standards organization in the cinema industry, published the Digital Cinema System Specification. This specification establishes standardized 2K and 4K container formats for digital cinema production, with resolutions of and respectively. The resolution of the video content inside follows the SMPTE 428-1 standard, which establishes the following resolutions for a 4K distribution:- 40962160
- 39962160
- 40961716
Some articles claim that the terms "2K" and "4K" were coined by DCI and refer exclusively to the 2K and 4K formats defined in the DCI standard. However, usage of these terms in the cinema industry predates the publication of the DCI standard, and they are generally understood as casual terms for any resolution approximately 2000 or 4000 pixels in width, rather than names for specific resolutions.
SMPTE UHDTV standard
In 2007, the Society of Motion Picture and Television Engineers published SMPTE ST 2036-1, which defines parameters for two UHDTV systems called UHDTV1 and UHDTV2. The standard defines the following characteristics for these systems:- A resolution of or
- Square pixels, for an overall image aspect ratio of
- A framerate of 23.976, 24, 25, 29.97, 30, 50, 59.94, 60, 100, 119.88, or 120Hz with progressive scan
- RGB, 4:4:4, 4:2:2, or 4:2:0 pixel encoding
- 10bpc or 12bpc color depth
- Colorimetry characteristics as defined in the standard, including color primaries, quantization parameters, and the electro-optical transfer function. These are the same characteristics later standardized in ITU-R BT.2020. UHDTV1 systems are permitted to use BT.709 color primaries up to 60Hz.
ITU-R UHDTV standard
Although the UHDTV standard does not define any official names for the formats it defines, ITU typically uses the terms "4K", "4K UHD", or "4K UHDTV" to refer to the system in public announcements and press releases. In some of ITU's other standards documents, the terms "UHDTV1" and "UHDTV2" are used as shorthand.
CEA Ultra HD
In October 2012, the Consumer Electronics Association announced their definition of the term Ultra High-Definition for use with marketing consumer display devices. CEA defines an Ultra HD product as a TV, monitor, or projector with the following characteristics:- A resolution of or larger
- An aspect ratio of 1.1 or wider
- Support for color depth of 8bpc or higher
- At least one HDMI input capable of supporting at 24, 30, and 60Hz progressive scan, and HDCP2.2
- Capable of processing images according to the color space defined in ITU-R BT.709
- Capable of upscaling HD content
2160p resolution
Some 4K resolutions, like, are often casually referred to as 2160p. This name follows from the previous naming convention used by HDTV and SDTV formats, which refer to a format by the number of pixels/lines along the vertical axis rather than the horizontal pixel count.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 due to its association with the well-known 720p and 1080p HDTV formats. Although 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 ; although this is a 2160p resolution, it is not a 4K resolution. Conversely, Samsung released a TV, but marketed it as a "4K" TV despite its 5K-class resolution.
M+ or RGBW TV controversy
In 2015, LG Display announced the implementation of a new technology called M+ which is the addition of white subpixel along with the regular RGB dots in their IPS panel technology. The media and internet users later called this "RGBW" TVs because of the white sub pixel.Most of the new M+ technology was employed on 4K TV sets which led to a controversy after tests showed that the addition of a white sub pixel replacing the traditional RGB structure would reduce the resolution by around 25%. After tests done by Intertek in which the technical aspects of LG M+ TVs were analyzed and they concluded that "the addressable resolution display is 2,880 X 2,160 for each red, green, blue", in other words, the LG TVs were technically 2.8K as it became known in the controversy. Although LG Display has developed this technology for use in notebook display, outdoor and smartphones, it is more popular in the TV market due to the supposed 4K UHD marketed resolution but still being incapable of achieving true 4K UHD resolution as defined by the CTA as 3840x2160 active pixels with 8-bit per color. This negatively impacts the rendering of text, making it a bit fuzzier, which is especially noticeable when a TV is used as a PC monitor.
CinemaWide 4K
In 2019, Sony was granted the CinemaWide trademark by the European Union Intellectual Property Office, in which the trademark covers 'Class 9' electronic devices, including smartphones. According to Sony and SID, the standard defines a CinemaWide 4K product with the following characteristics:- A resolution of or larger
- An aspect ratio of
- Capable of playing back 4K resolution video in an aspect ratio of
- Capable of upscaling non-4K content
Adoption
Video sharing website YouTube and the television industry have adopted 38402160 as their 4K standard., 4K content from major broadcasters remained limited. By late 2014, 4K content was becoming more widely available online, including on Apple TV, YouTube, Netflix, Hulu, and Amazon Prime Video.By 2013, some UHDTV models were available to general consumers in the range of US$600., prices on smaller computer and television panels had dropped below US$400.
ATSC
On March 26, 2013, the Advanced Television Systems Committee announced new proposals of a new standard called ATSC 3.0 which would implement UHD broadcasts at resolutions of up to or. The standard would also include framerates of up to 120Hz, HEVC encoding, wide color gamut, as well as high dynamic range.DVB
In 2014, the Digital Video Broadcasting Project released a new set of standards intended to guide the implementation of high resolution content in broadcast television. Dubbed DVB-UHDTV, it establishes two standards, known as UHD-1 and UHD-2. These standards use resolutions of 38402160 and 76804320 respectively, with framerates of up to 60Hz, color depth up to 10bpc, and HEVC encoding for transmission. DVB is currently focusing on the implementation of the UHD-1 standard.DVB finalized UHD-1 Phase 2 in 2016, with the introduction of service by broadcasters expected in 2017. UHD-1 Phase 2 adds features such as high dynamic range, wide color gamut, and high frame rate.
Video streaming
As of February 2025, both YouTube and Vimeo support high-resolution video uploads, with maximum resolutions of 4096 × 2304 pixels and 4096 × 2160 pixels, respectively. The growing availability of 4K content across streaming platforms like Netflix, Amazon Prime Video, and YouTube has made it more accessible to consumers. Vimeo's 4K content is currently limited to mostly nature documentaries and tech coverage.High Efficiency Video Coding facilitates streaming of 4K content at bitrates between 20 and, offering efficient compression without significant quality loss.
In January 2014, Naughty America launched the first adult video service streaming in 4K.
In February 2025, Super Bowl LIX was broadcast in 4K resolution with Dolby Vision HDR and Dolby Atmos sound for the first time. Fox aired the game, and it was also available for free streaming in 4K on Tubi, marking a significant milestone in sports broadcasting.
Mobile phone cameras
The first mobile phones to be able to record at 2160p were released in late 2013, including the Samsung Galaxy Note 3, which is able to record 2160p at 30 frames per second.In the year 2014, the OnePlus One was released with the option to record DCI 4K at 24 frames per second, as well as LG G3 and Samsung Galaxy Note 4 with optical image stabilization.
In the year 2015, Apple announced the iPhone 6s was released with the 12megapixel camera that has the option to record 4K at 25 or 30 frames per second.
In the years 2017 and 2018, mobile phone chipsets reached sufficient processing power that mobile phone vendors started releasing mobile phones that allow recording 2160p footage at 60 frames per second for a smoother and more realistic appearance.