Aspect ratio (image)

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The Aspect ratio of an image represents a proportional relationship between its width and its height. This is usually expressed as two numbers separated by a colon, as in 16: 9 . For the aspect ratio x : y , no matter how large or small the image is, if the width is divided into x units of the same length and height are measured using this same unit length, the height will be measured to be y unit.

For example, in a group of images all of which have a 16: 9 aspect ratio, one image may be 16 inches wide and 9 inches tall, 16 cm wide and 9 cm high, and the third width can be 8 yards and 4.5 yards high. Thus, the aspect ratio relates to the relationship from width to high, not the actual size of an image.

Video Aspect ratio (image)

Some common examples

The most common aspect ratios used today in theatrical presentations are 1.85: 1 and 2.39: 1. Two common aspect ratios of videography are 4: 3 (1.3 3 : 1) , 20th century universal video formats, and 16: 9 (1.7 7 : 1), universal for high-definition television and European digital television. Other cinema and video aspect ratios exist, but are rarely used.

In silent camera photography, the most common aspect ratio is 4: 3, 3: 2, and more recently found in consumer cameras, 16: 9. Other aspect ratios, such as 5: 3, 5: 4, and 1: 1 ( square format), also used in photography, especially in medium format and large format.

With television, DVD and Blu-ray Disc, changing the unequal ratio format is achieved by enlarging the original image to fill the viewing area of ​​the receiver format and bypass the excess image information (zoom in and out), by adding horizontal mattes (letterboxing) or vertical mattes ( pillarboxing) to maintain the aspect ratio of the original format, by stretching (thus distorting) the image to fill the recipient format ratios, or by scaling by different factors in both directions, possibly scale by different factors at the center and at the edge (as in < i> Wide Zoom mode ).

Maps Aspect ratio (image)

Practical limitations

In motion picture format, the physical size of the film area between the sprocket perforations determines the size of the image. The universal standard (founded by William Dickson and Thomas Edison in 1892) is a framework of four high perforations. The film itself has a width of 35 mm (1.38 inches), but the area between the perforations is 24.89 mm - 18.67 mm (0.980 inches at 0.735 inches), leaving the de facto ratio of 4: 3, or 1.3 3 : 1.

With space devoted to standard optical soundtracks, and reduced frame size to retain images that are wider than tall, this produces an Academy aperture of 22 mm - 16 mm (0.866 inches at 0.630 inches) or 1.375: 1 aspect ratios.

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Cinema termology

Image industry conventions provide a value of 1.0 on the image height; Anamorphic frames (since 1970, 2.39: 1) are often mis-described (rounded) as 2.40: 1 or 2.40 ("two-four-oh"). After 1952, a number of aspect ratios were experimented with anamorphic production, including 2.66: 1 and 2.55: 1. The SMPTE specification for anamorphic projection from 1957 (PH22.106-1957) ultimately standardized aperture to 2.35: 1. Renewal 1970 (PH22.106-1971) changed the aspect ratio to 2.39: 1 to make splices less visible. This aspect ratio of 2.39: 1 is confirmed by the latest revision of August 1993 (SMPTE 195-1993).

In American theaters, the general projection ratio is 1.85: 1 and 2.39: 1. Some European countries have 1.6 6 : 1 as the widescreen standard. The "Academy Ratio" 1,375: 1 was used for all cinema movies in the voice era until 1953 (with the release of George Stevens' Shane in 1.6 6 : 1). During that time, television, which had the same aspect ratio of 1,3 3 : 1, became a perceived threat to the film studio. Hollywood responded by creating a large number of widescreen formats: CinemaScope (up to 2.6 6 : 1), Todd-AO (2.20: 1), and VistaVision (initially 1.50: 1, now 1,6 6 : 1 to 2.00: 1) to name just a few. The aspect ratio 1.85: 1 "flat" was introduced in May 1953, and became one of the most common cinema projection standards in the US and elsewhere.

The purpose of these various lenses and aspect ratios is to capture as many frames as possible, to the widest possible area of ​​the film, to make full use of the film being used. Some aspect ratios are selected to use smaller movie sizes to save on film costs while other aspect ratios are selected to use larger movie sizes to produce a wider higher resolution image. In both cases, the image is squeezed horizontally to fit the film frame size and avoid unused film areas.

Movie camera system

The development of various film camera systems must ultimately satisfy the placement of frames in relation to the lateral constraint of perforation and the area of ​​the optical soundtrack. One of the smart widescreen alternatives, VistaVision, uses a 35 mm standard film that runs sideways through the camera gate, so that the sprocket holes are above and below the frame, allowing larger horizontal negative size per frame since only the vertical size is now limited by perforation. There are even a number of projectors built to also run the print film horizontally. In general, however, the 1.50: 1 ratio of the initial VistaVision image is optically transformed into a vertical mold (in standard 4-perforation 35 mm film) to be displayed with standard projectors available in theaters, and then affixed to the projector to US Standard 1.85 : 1. This format was briefly revived by Lucasfilm in the late 1970s for special effects work requiring larger negative sizes (due to image degradation of the optical printing steps required to create multi-layer composites). This is becoming obsolete mostly because of the better camera, lens, and film stock available for standard four-perforation formats, in addition to the increased laboratory costs for making prints compared to more standard vertical processes. (The horizontal process is also tailored to the 70 mm film by IMAX, first shown in Osaka '70 Worlds Fair.)

Super 16 mm film is often used for television production due to lower cost, lack of space for the soundtrack on the film itself (because it is not projected but transferred to the video), and the aspect ratio is similar to 16: 9 (the native Super 16 mm ratio is 15: 9). It can also be blown up to 35 mm for theatrical release and is therefore sometimes used for widescreen films.

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Current video standard

4: 3 standard

4: 3 (1,3 3 : 1) (generally read as "Four-Three" , "Four-by-Three" , or "Four-to-Three" ) for standard television has been used since the invention of moving image cameras and many computer monitors used to use the same aspect ratio. 4: 3 is the aspect ratio used for 35 mm film in the silent era. It is also very close to the 1,375: 1 Academy ratio, defined by the Academy of Art and Motion Picture Science as standard after the advent of sound-on-optical film. By matching this aspect ratio TV, the film originally photographed on 35 mm films can be satisfactorily seen on TV in the early days of the medium (ie the 1940s and 1950s). As the cinema's presence declines, Hollywood creates a widescreen aspect ratio (such as the previously mentioned 1.85: 1 ratio) to distinguish the film industry from TV. However, since the start of 21st century announcers around the world has gradually wiped out the 4: 3 standard, as manufacturers began supporting 16: 9/16: 10 aspect ratios of all modern high definition television sets, broadcast cameras, and computer monitors..

16: 9 standard

16: 9 (1.7 7 : 1) (commonly named "Sixteen-by-Nine" , "Sixteen-Nine" , and "Sixteen-to-Nine" ) is the international standard format of HDTV, non-HD digital television and PALplus analog screen television. Hi-Vision Japan originally started with a ratio of 5: 3 (= 15: 9) but was converted when the international standard group introduced a wider ratio of 5 1/3 to 3 (= 16: 9). Many digital video cameras that have 16: 9, and 16: 9 recording capability are the only widescreen aspect ratios supported natively by DVD standards. DVD manufacturers can also choose to display wider ratios such as 1.85: 1 and 2.39: 1 in a 16: 9 DVD frame with loud matting or adding a black bar inside the picture itself. However, it was often used on English TV in England in the 1990s before the 21st century. 18: 9 (2: 1) "> 18: 9 (2: 1) h3>

Since 1998, cinematographer Vittorio Storaro has advocated for a format called "Univisium" which uses the 18: 9 format (2: 1). It is designed to be a compromise between the cinema aspect ratio of 2.39: 1 and the 16: 9 HD-TV broadcast ratio. The univisium has gained little appeal in theatrical film market, but has recently been used by Netflix and Amazon Video for production such as > House of Cards and Transparent , respectively. This aspect ratio is the standard on the acquisition format mandated by this content platform and is not always a creative choice. In addition, some mobile devices, such as LG G6, LG V30, Huawei Mate 10 Pro, Google Pixel 2 XL and OnePlus 5T, embrace 18: 9 format, and Samsung Galaxy S8, Samsung Galaxy Note 8 and Samsung Galaxy S9 with 18, 5: 9. Apple iPhone X also has a similar screen ratio of 19.5: 9 (2.16: 1). 21: 9 (7: 3) "> 21: 9 (7: 3) h3>

21: 9 aspect ratio, the approximate true value of 64:27, is the ratio of the near cinematic film.

21: 9 aspect ratio is most often seen on higher end monitors, and is usually called an UltraWide monitor. <3.3: 1) 36:10 (3.6: 1) h3>

In 2016, IMAX announced the release of the movie in 'Ultra-WideScreen 3.6' format, with a 36:10 aspect ratio. A year later, Samsung and Phillips announced 'Super UltraWide displays', with a 32: 9 aspect ratio. The Ultra-WideScreen 3.6 video format did not spread, as the cinema in the larger ScreenX 270Ã, format was released.

Vertical video and square videos

Video consumption in social apps has grown tremendously and led to the emergence of new video formats that are more suitable for mobile devices that can be held in horizontal and vertical orientation. The square video is popularized by mobile apps like Instagram and has since been supported by other major social platforms including Facebook and Twitter. This can fill almost double the screen space compared to the 16: 9 format (when the device is held differently when seeing from how the video was recorded). Vertical video (9:16) was popularized by Snapchat and is now also adopted by Twitter and Facebook.

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Gaining height, width, and screen area

Seringkali, spesifikasi layar diberikan oleh panjang diagonal mereka. Rumus berikut dapat digunakan untuk menemukan tinggi ( h ), lebar ( w ) dan area ( A ), di mana r adalah singkatan dari rasio, ditulis sebagai pecahan, dan d untuk panjang diagonal.

${\ displaystyle h = {\ frac {d} {\ sqrt {r ^ {2} 1}}} \ qquad w = {\ frac {d} {\ sqrt {{\ frac {1} {r ^ {2}}} 1}}} \ qquad A = {\ frac {d ^ {2}} {r {\ frac {1} {r}}}}}  ÂÂ$

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Distinctions

This article primarily addresses the aspect ratio of images as they appear, which is more formally referred to as display aspect ratio (DAR). In digital images, there is a difference with the storage aspect ratio (SAR), which is the pixel dimension ratio. If an image is displayed with square pixels, then this ratio agrees; if not, then non-square pixels, "rectangles" are used, and this ratio is not appropriate. The pixel aspect ratio itself is known as the pixel aspect ratio (PAR) - for square pixels this is 1: 1 - and this is related to identity:

SARÃ, ÃÆ' â € "PARÃ, = Ã, DAR.

Rearranging (solving for PAR) results in:

PARÃ, = Ã, DAR/SAR.

For example, 480 480 Ã-VGA images have SAR 640/480 = 4: 3, and if displayed on a 4: 3 screen (DAR = 4: 3), have square pixels, then PAR of 1: 1 In contrast, the image 720Ã, ÃÆ'â € "576 D-1 PAL has SAR 720/576 = 5: 4, but is displayed on a 4: 3 screen (DAR = 4: 3), so with this formula it will have PAR (4: 3)/(5: 4 ) = 16:15.

However, since the standard definition digital video was originally based on analog digital television sampling, the horizontal 720 pixels actually capture images that are slightly wider to avoid the loss of the original analog image. In the actual picture, this extra pixel is partially or completely black, as only a central 704 horizontal pixel has an actual 4: 3 or 16: 9 image. Therefore, the actual pixel aspect ratio for PAL videos is slightly different from that given by the formula, especially 12:11 for PAL and 10:11 for NTSC. For consistency, the same effective pixel aspect ratio is used even for standard definition digital video originating in digital form rather than being changed from analog. For more details refer to the main article.

In analog images such as movies there are no pixel ideas, or SAR or PAR ideas, and the "aspect ratio" refers clearly to DAR. The actual view generally has no square pixels, although it may be a digital sensor; they are more of a mathematical abstraction used in resampling images to convert between resolutions.

Non-square pixels often appear in early digital TV standards, related to the digitization of analog TV signals - of different horizontal and vertical resolutions and thus best described by non-square pixels - as well as in some digital videocamer and computer display modes, such as Color Graphics Adapter (CGA). Today they appear mainly in transcoding between resolutions with different SARs.

DAR is also known as the image aspect ratio and image aspect ratio , although the latter can be confused with aspect ratio pixels .

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Visual comparisons

Comparing two different aspect ratios creates some subtlety - when comparing two aspect ratios, one can compare images of the same height, same width, same as the diagonal, or the same area. More amorphous questions include whether a particular subject matter has a natural aspect ratio (wide panoramas, high full length person image), or whether a certain ratio is more or less aesthetic, such as the golden ratio (~ 1.618).

Television and other screens usually include the size with diagonal. Given the same diagonal, the 4: 3 screen has more area compared to 16: 9. For CRT-based technology, the aspect ratio that is closer to square is cheaper to produce. The same applies to projectors, and other optical devices such as cameras, camcorders, etc. For LCD and plasma screens, the cost is more related to the area. Producing a wider and shorter screen can produce the same advertised diagonal, but with fewer areas.

Original Aspect Ratio (OAR) is the term home cinema for aspect ratio or dimension in which film or visual production is produced - as envisaged by the people involved in making the work. For example, the film Gladiator was released to the theaters in an aspect ratio of 2.39: 1. It was filmed in Super 35 and, in addition to being presented in theaters and television at Original Aspect Ratio 2.39: 1, it was also broadcast without matte, altering an aspect ratio to television standards 1.3 3 : 1. Due to the different ways of filming, IAR (Intended Aspect Ratio) is a more appropriate term, but is rarely used.

Modified aspect ratio (MAR)

Modified Aspect Ratio is the home cinema term for the aspect ratio or dimension in which the movie is modified to fit a particular screen type, compared to the original aspect ratio. Modified aspect ratio is usually 1.3 3 : 1 (historically), or (with the appearance of widescreen television set) 1.7 7 : 1 aspect ratio. 1.3 3 : 1 is a modified aspect ratio used historically in VHS format. A modified aspect ratio transfer is achieved by pan and scan or matte open, the latter meaning removes the cinematic matte from film 1.85: 1 to open the full frame 1.3 3 : 1. Another name for that is the aspect ratio "prescaled" ".

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Problems in movies and television

The dual aspect ratio creates an additional burden on filmmakers and consumers, and confusion among TV broadcasters. It is common for widescreen movies to be presented in an altered format (truncated, letterboxed or extended beyond the original aspect ratio). Also not infrequently windowboxing (when letterbox and pillarbox occur simultaneously). For example, a 16: 9 broadcast can embed 4: 3 ads in a 16: 9 drawing area. A standard 4: 3 television viewer (a non-widescreen display) will see 4: 3 commercial images with 2 sets of black, vertical and horizontal (windowboxing or stamp effect). A similar scenario can also occur for the owner of the widescreen set when viewing 16: 9 material embedded in a 4: 3 frame, then watching it in 16: 9. The Active Description format is the mechanism used in digital broadcasting to avoid this problem. It is also common that 4: 3 images are stretched horizontally to fit a 16: 9 screen to avoid pillar boxing but to change the image so that the subject appears short and fat.

Both PAL and NTSC have provisions for multiple data pulses contained in the video signal used for aspect ratio signals (See ITU-R BT.1119-1 - Widescreen broadcasting for broadcasting). These pulses are detected by a television set that has a wide screen and causes the television to automatically switch to 16: 9 display mode. When 4: 3 material is included (like the ads mentioned above), the television switches to 4: 3 display mode for displaying matter correctly. Where video signals are transmitted via a European SCART connection, one of the status lines is used to signal 16: 9 material as well.

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Still photography

The common aspect ratio in still photography includes:

• 1: 1
• 5: 4 (1.25: 1)
• 4: 3 (1,3 3 : 1)
• 3: 2 (1.5: 1)
• 5: 3 (1,6 6 : 1)
• 16: 9 (1.7 7 : 1)
• 3: 1

Many digital cameras still offer the user option to select multiple aspect ratio images. Some achieve this through the use of multi-aspect sensors (especially Panasonic), while others simply cut their original image format to have the output match the desired aspect ratio of the image.

1: 1

Is a classic box drawing, and is available as an option in some digital cameras, and is reminiscent of the days of film cameras when square images are popular with photographers using twin lens reflex cameras. This medium format camera uses 120 films rolled into rolls. Image size 6 ÃÆ'â € "6Ã, cm is a classic 1: 1 format in the past. 120 films can still be found and used today. Many Polaroid instant films are designed as a square format. Further until August 2015, Instagram photo-sharing sites only allow users to upload images in 1: 1 format.

5: 4

Common in large and medium format photography, and still commonly used for prints from digital cameras in size 8 "ÃÆ' â €" 10 ".

4: 3

Used by most digital point-and-shoot cameras, Four Thirds systems, Micro Four Thirds system cameras and 645 medium format cameras. The popularity of the 4: 3 digital format was developed to match the current digital display, a 4: 3 computer monitor.

Several subsequent formats have their roots in classic film photographic image sizes, both 35 mm film cameras, and several Advanced Photo System (APS) film cameras. The APS camera is capable of selecting one of three image formats, APS-H ("High Definition" mode), APS-C ("Classic" mode) and APS-P ("panorama" mode).

3: 2

used by 35mm classic film cameras using image sizes 24 mm - 36 mm, and their digital derivatives are represented by DSLR. The typical DSLR comes in two flavors, called a professional "full frame" sensor (24 mm x 36 mm) and smaller variations, called "APS-C" sensors. The term "APS" comes from another movie format known as APS and "-C" refers to the "Classic" mode, which exposes the image over a smaller area (25.1 mm × 16.7 mm) but retains the same "classic" 3: 2 proportions as 35 mm full frame film cameras.

When discussing DSLRs and their non-SLR derivatives, the term APS-C has become an almost common term. Two major camera manufacturers Canon and Nikon each developed and set the standard sensor for their own version of APS-C sized and proportional sensor. Canon actually developed two standards, APS-C and a slightly larger APS-H area (not to be confused with the APS-H movie format), while Nikon developed its own APS-C standard, called DX. Regardless of the various types of sensors, and their varying sizes, they are fairly close to the original APS-C image size, and retain the proportion of classic 3: 2 drawings commonly known as "APS-C" size sensors.

The reason for DSLR image sensors being 3: 2 flatter compared to the higher 4: 3 point-and-snap point is that the DSLR is designed to match 35mm legacy SLR films, while the majority of digital cameras are designed to match the dominant computer. time display, with VGA, SVGA, XGA and UXGA all 4: 3. Widescreen computer monitors did not become popular until the advent of HDTV, which used a 16: 9 image aspect ratio.

16: 9

16: 9 is another format that is rooted in the APS film cameras. Known as APS-H (30.2 mm × 16.7 mm), with "-H" indicating "High Definition", the 16: 9 format is also the standard aspect ratio for HDTV images. 16: 9 is increasingly popular as a format in all consumer photo camera classes that also record High Definition (HD) video. While the camera still has HD video capabilities, some can also record still images in 16: 9 format, ideal for viewing on HD television and widescreen computer screens.

3: 1

is another format that can find its roots in APS movie cameras. Known as APS-P (30.2 ÃÆ'â € "9.5Ã, mm), with -P" signifies "Panorama", the 3: 1 format is used for panoramic photography.The APS-P panorama standard is the least adhered to APS standards. , and the application of panorama varies with the manufacturer on different cameras, with the only similarity being that the image is longer than tall, in the classical "panorama" style.

Common print sizes in the US (in inches) include 4ÃÆ' â € "6 (1,5), 5ÃÆ' â €" 7 (1,4), 4ÃÆ' â € "5 and 8ÃÆ'â €" 10 (1.25), and 11ÃÆ' â € "14 (1.27); Large format cameras typically use one of these aspect ratios. Medium-format cameras typically have a format determined by the nominal size in centimeters (6ÃÆ' â € "6, 6ÃÆ' â €" 7, 6ÃÆ' â € "9, 6ÃÆ' â €" 4.5), but these numbers should not be interpreted as precise in computational aspect ratio. For example, the height that can be used from 120-format roll film is 56mm, so the 70mm width (as in 6ÃÆ'â € "7) generates a 4: 5 aspect ratio - ideal for zooming to make portraits 8ÃÆ' â €" 10 ". is determined by their portrait dimensions (height) while the aspect ratio of the equipment is determined by their landscape dimension (wide, upside down). A good example of this 4ÃÆ'-6 print (width of 6 inches by 4 inches high) perfectly fits the 3: 2 of DSLR/35 mm, since 6/2 = 3 and 4/2 = 2.

For analog projections of photo slide, the projector and screen use the 1: 1 aspect ratio, supporting horizontal and vertical orientation equally well. In contrast, digital projection technology typically supports vertically oriented images only on a fraction of the landscape-oriented image resolution. For example, projecting a digital still image that has a 3: 2 aspect ratio on a 16: 9 projector uses 84.3% of the available resolution in horizontal orientation, but only 37.5% in the vertical orientation.

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See also

• Description of Active Format (AFD)
• Film terminology index
• Paper size
• Portrait and protect
• Glossary of terms

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Note

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References

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External links

• "NEC Monitor Technology Guide". Archived from the original on 2006-05-21 . Retrieved 2006-07-24 .
• Mailbox and Widescreen Advocacy Page
• American Widescreen Museum
• Widescreen Apertures and Aspect Ratios
• Aspects - combined aspect ratio, frame size, and bitrate calculator on Wayback Machine (archived December 7, 2013)
• "Calculator for Setting 4: 3 Image Size on 16: 9" Screen. Archived from the original on 2010-08-01 . Obtained 2006-09-14 . (middle of page)
• Aspect Ratio Explained: Part 1 Part 2
• Description of the TV Aspect Ratio Modeling description code
• Display aspect ratio and pixel aspect ratio used in TV and video apps.
• IMDb - Number of DVDs for each aspect ratio on the Wayback Machine (archived June 24, 2009)
• SCADplus: 16: 9 Action plan for television in screen format 16: 9 - EU
• Aspect Ratio Calculator
• Online tools to calculate new dimensions that maintain the same aspect ratio
• ARCalculator - Good ratio aspect, image ratio, size converter and calculator

Source of the article : Wikipedia