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Letter-boxing is the practice of transferring film shot in a widescreen aspect ratio to standard-width video formats while preserving the film's original aspect ratio. The resulting video-graphic image has mattes of empty space above and below it; these mattes are part of each frame of the video signal.
The term refers to the shape of a letter-box, a slot in a wall or door through which mail is delivered, being rectangular and wider than it is high. [1]
The first use of letter-boxing in consumer video appeared with the RCA Capacitance Electronic Disc (CED) videodisc format. Initially, letter-boxing was limited to several key sequences of a film such as opening and closing credits, but was later used for entire films. The first fully letter-boxed CED release was Amarcord in the past century, and several others followed including The Long Goodbye , Monty Python and the Holy Grail and The King of Hearts . [2] Each disc contains a label noting the use of "RCA's innovative wide-screen mastering technique." [3]
The term "SmileBox" is a registered trademark [4] used to describe a type of letter-boxing for Cinerama films, such as on the Blu-ray release of How the West Was Won . The image is produced by using a map projection-like technique to approximate how the picture might look if projected onto a curved Cinerama screen. [5]
Digital broadcasting allows 1.78:1 widescreen format transmissions without losing resolution, and thus widescreen is the television norm. Most television channels in Europe are broadcasting standard-definition programming in 1.78:1, while in the USA, these are down-scaled to letterbox. When using a 1.33:1 screen, it is possible to display such programming in either a letter-boxing format or in a 1.33:1 center-cut format (where the edges of the picture are lost).
A letter-boxed 1.56:1 compromise ratio was often broadcast in analogue transmissions in European countries making the transition from 1.33:1 to 1.78:1. In addition, recent years have seen an increase of "fake" 2.40:1 letterbox mattes on television to give the impression of a cinema film, often seen in adverts, trailers or tv such as Top Gear . [6]
Current high-definition television systems use video displays with a wider aspect ratio than older television sets, making it easier to accurately display widescreen films. In addition to films produced for the cinema, some television programming is produced in high definition widescreen.
On a widescreen television set, a 1.78:1 image fills the screen; however, 21:9 aspect ratio films are letter-boxed with narrow mattes. Because the 1.85:1 aspect ratio does not match the 1.78:1 aspect ratio of widescreen video, slight letter-boxing occurs. Usually, such matting of 1.85:1 film is eliminated to match the 1.78:1 aspect ratio in the image transference.
Letterbox mattes are not necessarily black. IBM has used blue mattes for many of their TV ads, yellow mattes in their "I am Superman" Lotus ads, and green mattes in ads about efficiency & environmental sustainability. Others uses of colored mattes appear in ads from Allstate, Aleve, and Kodak among others, and in music videos such as Zebraheads, "Playmate of the Year". In other instances mattes are animated, such as in the music video for "Never Gonna Stop (The Red Red Kroovy)", and even parodied such as the final scene of the Crazy Frog Axel F music video in which Crazy Frog peeks over the matte on the lower edge of the screen with part of his hands overlapping the matte. Similar to breaking the border of a comic's panel, it is a form of breaking the fourth wall. [7] The 2016 Ghostbusters exploited the edges for its 3D effects, with visual effects that "spilled over" into the letter-boxed areas. [8]
The table below shows which TV lines will contain picture information when letterbox pictures are displayed on either 1.33:1 or 1.78:1 screens.
| Aspect Ratio on 1.33:1 screen | 525 Line System | 625 Line System | Aspect Ratio on 1.78:1 screen | 525 Line System | 625 Line System | 1080 HD Line System | |||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| 1.33:1 | 21–263 | 284–525 | 23–310 | 336–623 | — | — | — | — | — | — | — |
| 1.56:1 | 40–245 | 302–508 | 44–289 | 357–602 | — | — | — | — | — | — | — |
| 1.78:1 | 52–232 | 315–495 | 59–282 | 372–587 | 1.78:1 | 21–263 | 284–525 | 23–310 | 336–623 | 21–560 | 584–1123 |
| 1.85:1 | 56–229 | 320–491 | 64–270 | 376–582 | 1.85:1 | 26–257 | 289–520 | 29–304 | 342–617 | 31–549 | 594–1112 |
| 2.40:1 | 73–209 | 336–472 | 85–248 | 398–561 | 2.40:1 | 50–231 | 313–495 | 58–275 | 371–588 | 86–494 | 649–1057 |
Pillar-boxing is the display of an image within a wider image frame by adding lateral mattes (vertical bars at the sides); for example, a 1.33:1 image has lateral mattes when displayed on a 16:9 aspect ratio television screen.
An alternative to pillar-boxing is "tilt-and-scan" (reversed pan and scan), horizontally matting the original 1.33:1 television images to the 1.78:1 aspect ratio, which at any given moment crops part of the top and/or bottom of the frame, hence the need for the "tilt" component. A tilt is a camera move in which the camera tilts up or down.
Window-boxing occurs when an image appears centered in a television screen, with blank space on all four sides of the image, [9] [10] such as when a widescreen image that has been previously letter-boxed to fit 1.33:1 is then pillar-boxed to fit 1.78:1. It is also called "matchbox", "gutter box", and "postage stamp" display. This occurs on the DVD editions of the Star Trek films on a 1.33:1 tv when the included widescreen documentaries show footage from the original series. It is also seen in The Crocodile Hunter: Collision Course , which displays widescreen pillar-boxing with 1.85:1 scenes in a 2.40:1 frame that is subsequently letter-boxed. It is common to see window-boxed commercials on tv networks, because many commercials are shot in 1.78:1 but distributed to networks in non-widescreen, letter-boxed to fit 1.33:1.
A specific kind of letter-boxing is used as an anti-fingerprinting technique so that it becomes harder to uniquely identify internet users based on the screen resolution of their browsers or devices. The idea is that, when a user resizes or maximizes their browser window, the window's real dimensions are masked by keeping the window width and height at multiples of a certain ratio. The remaining space of the page on either top, bottom, left, or right are then left empty. As a result, individual users will have the same reported window dimensions as many others. A working example of this technique was developed by Mozilla, based on an earlier experiment by Tor Project, and is used in the Tor Browser. [11]
Pan and scan is a method of adjusting widescreen film images so that they can be shown in fullscreen proportions of a standard-definition 4:3 aspect ratio television screen, often cropping off the sides of the original widescreen image to focus on the composition's most important aspects.
Standard-definition television is a television system that uses a resolution that is not considered to be either high or enhanced definition. Standard refers to offering a similar resolution to the analog broadcast systems used when it was introduced.
Widescreen images are displayed within a set of aspect ratios used in film, television and computer screens. In film, a widescreen film is any film image with a width-to-height aspect ratio greater than 4:3 (12:9).
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.
16:9 (1.78:1) is a widescreen aspect ratio with a width of 16 units and height of 9 units.
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.
Cropping is the removal of unwanted outer areas from a photographic or illustrated image. The process usually consists of the removal of some of the peripheral areas of an image to remove extraneous visual data from the picture, improve its framing, change the aspect ratio, or accentuate or isolate the subject matter from its background. Depending on the application, this can be performed on a physical photograph, artwork, or film footage, or it can be achieved digitally by using image editing software. The process of cropping is common to the photographic, film processing, broadcasting, graphic design, and printing businesses.
14:9 is a compromise aspect ratio between 4:3 and 16:9. It is used to create an acceptable picture on both 4:3 and 16:9 TV, conceived following audience tests conducted by the BBC. It has been used by most UK, Irish, French, Spanish, Colombian and Australian terrestrial analogue networks, and in the US on Warner Bros. Discovery' HD simulcast channels with programming and advertising originally compiled in 4:3. Note that 14:9 is not a shooting format; 14:9 material is almost always derived from either a 16:9 or 4:3 shot, and no televisions have ever been made in 14:9.
Open matte is a filming technique that involves matting out the top and bottom of the film frame in the movie projector for the widescreen theatrical release and then scanning the film without a matte for a full screen home video release. It is roughly equivalent to an uncropped version of the film.
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.
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.
Widescreen televisions provide several modes for displaying video from 4:3 sources. These modes may be selected manually from a remote control, or automatically if an Active Format Description is available.
Windowboxing in the display of film or video occurs when the aspect ratio of the media is such that the letterbox effect and pillarbox effect occur simultaneously. Sometimes, by accident or design, a standard ratio image is presented in the central portion of a letterbox picture, resulting in a black border all around. It is generally disliked because it wastes much screen space and reduces the resolution of the original image. It can occur when a 16:9 film is set to 4:3 (letterbox), but then shown on a 16:9 TV or other output device. It can also occur in the opposite direction and a few films have been released with this aspect ratio — one example is The Crocodile Hunter: Collision Course, which had numerous scenes with Steve & Terri Irwin using widescreen pillar boxing.
The technology of television has evolved since its early days using a mechanical system invented by Paul Gottlieb Nipkow in 1884. Every television system works on the scanning principle first implemented in the rotating disk scanner of Nipkow. This turns a two-dimensional image into a time series of signals that represent the brightness and color of each resolvable element of the picture. By repeating a two-dimensional image quickly enough, the impression of motion can be transmitted as well. For the receiving apparatus to reconstruct the image, synchronization information is included in the signal to allow proper placement of each line within the image and to identify when a complete image has been transmitted and a new image is to follow.
The display aspect ratio (or DAR) is the aspect ratio of a display device and so the proportional relationship between the physical width and the height of the display. It is expressed as two numbers separated by a colon (x:y), where x corresponds to the width and y to the height. Common aspect ratios for displays, past and present, include 5:4, 4:3, 16:10, and 16:9.
"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 graphics display resolution is the width and height dimension of an electronic visual display device, measured in pixels. This information is used for electronic devices such as a computer monitor. Certain combinations of width and height are standardized and typically given a name and an initialism which is descriptive of its dimensions. A graphics display resolution can be used in tandem with the size of the graphics display to calculate pixel density. An increase in the pixel density often correlates with a decrease in the size of individual pixels on a display.
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.
Ultrawide formats refers to photos, videos, and displays with aspect ratios greater than 2. There were multiple moves in history towards wider formats, including one by Disney, with some of them being more successful than others.
