Video scaler

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An enlargement of a small section of a 1024x768 (VESA XGA) resolution image; the individual pixels are more visible in its scaled form than its normal resolution. ImagePixels.png
An enlargement of a small section of a 1024x768 (VESA XGA) resolution image; the individual pixels are more visible in its scaled form than its normal resolution.

A video scaler is a system which converts video signals from one display resolution to another; typically, scalers are used to convert a signal from a lower resolution (such as 480p standard definition) to a higher resolution (such as 1080i high definition), a process known as "upconversion" or "upscaling" (by contrast, converting from high to low resolution is known as "downconversion" or "downscaling").

Contents

Video scalers are typically found inside consumer electronics devices such as televisions, video game consoles, and DVD or Blu-ray players, but can also be found in other AV equipment (such as video editing and television broadcasting equipment). Video scalers can also be completely separate devices, often providing simple video switching capabilities. These units are commonly found as part of home theatre or projected presentation systems. They are often combined with other video processing devices or algorithms to create a video processor that improves the apparent definition of video signals.

Video scalers are primarily a digital device; however, they can be combined with an analog-to-digital converter (ADC, or digitizer) and a digital-to-analog converter (DAC) to support analog inputs and outputs.

Process

This is a comparison of several common video resolutions. The more pixels in an image the greater the possibility for finer detail and fidelity. ResolutionComparison.gif
This is a comparison of several common video resolutions. The more pixels in an image the greater the possibility for finer detail and fidelity.

The native resolution of a display is how many physical pixels make up each row and column of the visible area on the display's output surface. [1] There are many different video signals in use which are not the same resolution (neither are all of the displays), thus some form of resolution adaptation is required to properly frame a video signal to a display device. For example, within the United States, there are NTSC, ATSC, and VESA video standards each with several different resolution video formats. Multiple common resolutions are also used for high-definition television; 720p, 1080i, and 1080p.

While scaling a video signal does allow it to match the size of a particular display, the process can result in an increased number of visual artifacts in the signal, such as ringing and posterization.

Scaling by television channels

Television channels which air a mixture of 16:9 (or high-definition) programming and 4:3 (or standard definition) programming may employ scaling and/or cropping in order to make the programming fill the entire screen, as opposed to pillarboxing the feed instead, in order to maintain consistency in format. [2] [3] Likewise, broadcasters downscale programming produced in 16:9 for broadcast on their 4:3 feeds through letterboxing—either as a full 16:9 letterbox, or a partial 14:9 letterbox—a technique used primarily by European broadcasters during the transition to digital terrestrial television. [4] [5] The Active Format Description standard is a system of variables defining various scaling, letterboxing, and pillarboxing states; broadcasting equipment and televisions can be configured to automatically switch to the appropriate state based on the AFD flag encoded in the content and the aspect ratio of the display. [6]

When the U.S. cable network TNT introduced an HD feed in 2004, it controversially employed a stretching system known as FlexView (which was also offered to other broadcasters). FlexView used a nonlinear method to stretch more near the edges of the screen than in the center of it. The practice was imposed by the senior vice president of broadcast engineering at TNT, Clyde D. Smith, who argued that pillarboxing led to inconsistency between programs for viewers, could cause burn-in on plasma televisions, some older HDTVs could not stretch 4:3 content automatically, and the quality of stretching on some displays was poor. [2] Despite TNT's intentions, the system was frequently criticized by viewers of high definition channels, with some nicknaming the effect "Stretch-O-Vision". [2] [7]

In 2014, FXX faced similar criticism for its use of cropping and scaling on reruns of The Simpsons (which only started producing episodes in HD beginning in its 20th season), as its cropping method caused various visual gags to be lost. In February 2015, FXX announced that in response to these complaints, it would present these episodes in their original 4:3 aspect ratio on its video-on-demand service. [3] [8]

Since about 2008, some networks and cable companies have run high-definition versions of old programing that was originally shot on film shown in the 4:3 format. This format always cropped the sides of the image. For example, syndicated broadcast stations and the cable network TBS air Seinfeld in HD. The series producer, Sony Pictures went to the 35mm film source, making new HD masters and cropping the top and bottom parts of the frame, while restoring the sides. [9]

AI upscaling

In 2023, video upscaling products using generative artificial intelligence were previewed or released, such as NVIDIA's Video Super Resolution and Adobe's Project Res-Up. Unlike previous upscaling systems, these technologies generated new data based on provided video frames. [10] [11] [12]

See also

Related Research Articles

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Enhanced-definition television, or extended-definition television (EDTV) is a Consumer Electronics Association (CEA) marketing shorthand term for certain digital television (DTV) formats and devices. Specifically, this term defines an extension of the standard-definition television (SDTV) format that enables a clearer picture during high-motion scenes compared to previous iterations of SDTV, but not producing images as detailed as high-definition television (HDTV).

Anamorphic widescreen is a process by which a comparatively wide widescreen image is horizontally compressed to fit into a storage medium with a narrower aspect ratio, reducing the horizontal resolution of the image while keeping its full original vertical resolution. Compatible play-back equipment can then expand the horizontal dimension to show the original widescreen image. This is typically used to allow one to store widescreen images on a medium that was originally intended for a narrower ratio, while using as much of the frame – and therefore recording as much detail – as possible.

<span class="mw-page-title-main">Display resolution</span> Width and height of a display in pixels

The display resolution or display modes of a digital television, computer monitor, or other display device is the number of distinct pixels in each dimension that can be displayed. It can be an ambiguous term especially as the displayed resolution is controlled by different factors in cathode ray tube (CRT) displays, flat-panel displays and projection displays using fixed picture-element (pixel) arrays.

PALplus is an analogue television broadcasting system aimed to improve and enhance the PAL format by allowing 16:9 aspect ratio broadcasts, while remaining compatible with existing television receivers, defined by International Telecommunication Union (ITU) recommendation BT.1197-1. Introduced in 1993, it followed experiences with the HD-MAC and D2-MAC, hybrid analogue-digital widescreen formats that were incompatible with PAL receivers. It was developed at the University of Dortmund in Germany, in cooperation with German terrestrial broadcasters and European and Japanese manufacturers. The system had some adoption across Europe during the late 1990s and helped introduce widescreen TVs in the market, but never became mainstream.

In television technology, Wide Screen Signaling (WSS) is digital metadata embedded in invisible part of the analog TV signal describing qualities of the broadcast, in particular the intended aspect ratio of the image. This allows television broadcasters to enable both 4:3 and 16:9 television sets to optimally present pictures transmitted in either format, by displaying them in full screen, letterbox, widescreen, pillar-box, zoomed letterbox, etc.

1080i is a combination of frame resolution and scan type. 1080i is used in high-definition television (HDTV) and high-definition video. The number "1080" refers to the number of horizontal lines on the screen. The "i" is an abbreviation for "interlaced"; this indicates that only the even lines of each frame, then only the odd lines, are drawn alternately, so that only half the number of lines are ever updated at once. A related display resolution is 1080p, which also has 1080 lines of resolution; the "p" refers to progressive scan, which indicates that each full frame appears on the screen in sequence.

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<span class="mw-page-title-main">14:9 aspect ratio</span> Television image format

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<span class="mw-page-title-main">1080p</span> Video mode

1080p is a set of HDTV high-definition video modes characterized by 1,920 pixels displayed across the screen horizontally and 1,080 pixels down the screen vertically; the p stands for progressive scan, i.e. non-interlaced. The term usually assumes a widescreen aspect ratio of 16:9, implying a resolution of 2.1 megapixels. It is often marketed as Full HD or FHD, to contrast 1080p with 720p resolution screens. Although 1080p is sometimes referred to as 2K resolution, other sources differentiate between 1080p and (true) 2K resolution.

<span class="mw-page-title-main">HD ready</span> European certification label

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<span class="mw-page-title-main">Pillarbox</span> Black bars on the sides of an image

The pillarbox effect occurs in widescreen video displays when black bars are placed on the sides of the image. It becomes necessary when film or video that was not originally designed for widescreen is shown on a widescreen display, or a narrower widescreen image is displayed within a wider aspect ratio, such as a 16:9 image in a 2.39:1 frame. The original material is shrunk and placed in the middle of the widescreen frame.

<span class="mw-page-title-main">ATSC tuner</span> Tuner for digital television channels

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In television technology, Active Format Description (AFD) is a standard set of codes that can be sent in the MPEG video stream or in the baseband SDI video signal that carries information about their aspect ratio and other active picture characteristics. It has been used by television broadcasters to enable both 4:3 and 16:9 television sets to optimally present pictures transmitted in either format. It has also been used by broadcasters to dynamically control how down-conversion equipment formats widescreen 16:9 pictures for 4:3 displays.

Digital television in the United States is available via digital terrestrial television (DTT), digital cable, satellite television, and IPTV providers.

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"21:9" is a consumer electronics (CE) marketing term to describe the ultrawide aspect ratio of 64:27, designed to show films recorded in CinemaScope and equivalent modern anamorphic formats. The main benefit of this screen aspect ratio is a constant display height when displaying other content with a lesser aspect ratio.

The aspect ratio of an image is the ratio of its width to its height. It is expressed as two numbers separated by a colon, width:height. Common aspect ratios are 1.85:1 and 2.40:1 in cinematography, 4:3 and 16:9 in television, and 3:2 in still photography.

References

  1. ↑ "Video Upscaling for better viewing experience". hometoys.com. 2011-05-25. Retrieved 2013-03-07.
  2. 1 2 3 "TNT Stretches for HD". TV Week. Retrieved 2008-08-10.
  3. 1 2 "FXX will finally stream The Simpsons in original 4:3 format". The Verge. 13 February 2015. Retrieved 13 February 2015.
  4. ↑ Bob Wolfley (September 2, 2010). "Fox Sports taking a wider view of football". Milwaukee Journal Sentinel . Journal Communications. Archived from the original on September 5, 2010.
  5. ↑ "Beyond HD". BBC Academy. Retrieved 3 June 2015.
  6. ↑ "Managing AFD: Keep image format under your control". TV Technology. January 2009. Retrieved 5 June 2016.
  7. ↑ "Just say no to stretch-o-vision". EngadgetHD. Retrieved 2008-08-10.
  8. ↑ "FXX ruins the punchline by inexplicably cropping old standard definition 'Simpsons' episodes". The Verge. 24 August 2014. Retrieved 13 February 2015.
  9. ↑ "Seinfeld goes HD on TBS HD". AOL. September 3, 2008. Archived from the original on January 16, 2013. Retrieved July 24, 2019.
  10. ↑ Anderson, Ross (9 December 2023). "The Best AI Tool You're Not Using is Video Upscaling". The New York Sun .
  11. ↑ Weatherbed, Jess (11 October 2023). "Adobe previews AI upscaling to make old, fuzzy videos and GIFs look fresh". The Verge .
  12. ↑ Chacos, Brad (28 February 2023). "Tested: Nvidia's RTX Video Super Resolution is like going from VHS to Blu-ray". PC World .
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