Avideo scaleris a system that convertsvideosignals from onedisplay resolutionto another; typically, scalers are used to convert a signal from a lower resolution (such as480pstandard definition) to a higher resolution (such as1080ihigh definition), a process known as "upconversion" or "upscaling" (by contrast, converting from high to low resolution is known as "downconversion" or "downscaling" ).
Video scalers are typically found insideconsumer electronicsdevices such astelevisions,video game consoles,andDVDorBlu-rayplayers, but can also be found in other AV equipment (such asvideo editingandtelevision broadcastingequipment). Video scalers can also be completely separate devices, often providing simplevideo switchingcapabilities. These units are commonly found as part ofhome theatreor projected presentation systems. They are often combined with othervideo processingdevices or algorithms to create a video processor thatimproves the apparent definitionof video signals.
Video scalers are primarily adigitaldevice; however, they can be combined with ananalog-to-digital converter(ADC, or digitizer) and adigital-to-analog converter(DAC) to supportanaloginputs and outputs.
Process
editThis sectionneeds additional citations forverification.(July 2022) |
Thenative resolutionof 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 theUnited States,there areNTSC,ATSC,andVESAvideo standards each with several different resolution video formats. Multiple common resolutions are also used forhigh-definition television;720p,1080i,and1080p.
While scaling a video signal does allow it to match the size of a particular display, the process can result in an increased number ofvisual artifactsin the signal, such asringingandposterization.
Scaling by television channels
editTelevision channels that air a mixture of16:9(orhigh-definition) programming and4:3(or standard definition) programming may employ scaling or cropping in order to make the programming fill the entire screen, as opposed topillarbo xingthe 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 throughletterbo xing—either as a full 16:9 letterbox, or a partial14:9letterbox—a technique used primarily by European broadcasters during the transition todigital terrestrial television.[4][5]TheActive Format Descriptionstandard is a system of variables defining various scaling, letterbo xing, and pillarbo xing 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 networkTNTintroduced an HD feed in2004,it controversially employed a stretching system known as FlexView (which was also offered to other broadcasters). FlexView used anonlinear methodto stretch more near the edges of the screen than in the center of it. The practice was imposed by the senior vice president ofbroadcast engineeringat TNT, Clyde D. Smith, who argued that pillarbo xing led to inconsistency between programs for viewers, could causeburn-inonplasma 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,FXXfaced similar criticism for its use of cropping and scaling on reruns ofThe Simpsons(which only started producing episodes in HD beginning in its 20th season), as its cropping method caused variousvisual gagsto 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 programming 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 networkTBSairSeinfeldin HD. The series producer, Sony Pictures went to the35mm filmsource, making new HD masters and cropping the top and bottom parts of the frame, while restoring the sides.[9]
AI upscaling
editIn 2023, video upscaling products usinggenerative artificial intelligencewere previewed or released, such as NVIDIA'sVideo Super ResolutionandAdobe's Project Res-Up. Unlike previous upscaling systems, these technologies generated new data based on provided video frames.[10][11][12]
See also
editReferences
edit- ^"Video Upscaling for better viewing experience".hometoys. 2011-05-25.Retrieved2013-03-07.
- ^abc"TNT Stretches for HD".TV Week.Retrieved2008-08-10.
- ^ab"FXX will finally stream The Simpsons in original 4:3 format".The Verge.13 February 2015.Retrieved13 February2015.
- ^Bob Wolfley (September 2, 2010)."Fox Sports taking a wider view of football".Milwaukee Journal Sentinel.Journal Communications.Archived fromthe originalon September 5, 2010.
- ^"Beyond HD".BBC Academy.Retrieved3 June2015.
- ^"Managing AFD: Keep image format under your control".TV Technology.January 2009.Retrieved5 June2016.
- ^"Just say no to stretch-o-vision".EngadgetHD.Retrieved2008-08-10.
- ^"FXX ruins the punchline by inexplicably cropping old standard definition 'Simpsons' episodes".The Verge.24 August 2014.Retrieved13 February2015.
- ^"Seinfeld goes HD on TBS HD".AOL. September 3, 2008. Archived fromthe originalon January 16, 2013.RetrievedJuly 24,2019.
- ^Anderson, Ross (9 December 2023)."The Best AI Tool You're Not Using is Video Upscaling".The New York Sun.
- ^Weatherbed, Jess (11 October 2023)."Adobe previews AI upscaling to make old, fuzzy videos and GIFs look fresh".The Verge.
- ^Chacos, Brad (28 February 2023)."Tested: Nvidia's RTX Video Super Resolution is like going from VHS to Blu-ray".PC World.