Aspect ratio (image)
The aspect ratio of an image describes the proportional relationship between its width and its height. It is commonly expressed as two separated by a colon, as in 16,9.5 yards high. The most common ratios used today in the presentation of films in cinemas are 1.85,1 and 2.39,1. Two common videographic aspect ratios are 4,3, the video format of the 20th century. Other cinema and video aspect ratios exist, but are used infrequently, in still camera photography, the most common aspect ratios are 4,3,3,2, and more recently being found in consumer cameras 16,9. Other aspect ratios, such as 5,3,5,4, in motion picture formats, the physical size of the film area between the sprocket perforations determines the images size. The universal standard is a frame that is four perforations high, the film itself is 35 mm wide, but the area between the perforations is 24.89 mm×18.67 mm, leaving the de facto ratio of 4,3, or 1.33,1. A4,3 ratio mimics human eyesight visual angle of 155°h x 120°v, the motion picture industry convention assigns a value of 1.0 to the image’s height, an anamorphic frame is often incorrectly described as 2.40,1 or 2.40.
After 1952, a number of aspect ratios were experimented with for anamorphic productions, a SMPTE specification for anamorphic projection from 1957 finally standardized the aperture to 2.35,1. An update in 1970 changed the ratio to 2.39,1 in order to make splices less noticeable. This aspect ratio of 2.39,1 was confirmed by the most recent revision from August 1993, in American cinemas, the common projection ratios are 1.85,1 and 2.39,1. Some European countries have 1.66,1 as the wide screen standard, the Academy ratio of 1.375,1 was used for all cinema films in the sound era until 1953. During that time, which had a aspect ratio of 1.33,1. Hollywood responded by creating a number of wide-screen formats, CinemaScope, Todd-AO. The flat 1.85,1 aspect ratio was introduced in May 1953, and became one of the most common cinema projection standards in the U. S. and elsewhere. The goal of these lenses and aspect ratios was to capture as much of the frame as possible, onto as large an area of the film as possible.
In either case the image was squeezed horizontally to fit the frame size. Development of various film camera systems must ultimately cater to the placement of the frame in relation to the constraints of the perforations
Teletext is a television information retrieval service created in the United Kingdom in the early 1970s by the Philips Lead Designer for VDUs, John Adams. It offers a range of text-based information, typically including news, paged subtitle information is transmitted within the television signal. It is closely linked to the PAL broadcast system used in Europe, other teletext systems have been developed to work with the SECAM and NTSC systems, but teletext failed to gain widespread acceptance in North America and other areas where NTSC is used. In contrast, teletext is nearly ubiquitous across Europe as well as other regions. Common teletext services include TV schedules, regularly updated current affairs and sport news, Teletext is broadcast in numbered pages. For example, a list of news headlines appear on page 110. The broadcaster constantly sends out pages in sequence, there will typically be a delay of a few seconds from requesting the page and it being broadcast and displayed, the time being entirely dependent in the number of pages being broadcast.
More sophisticated receivers use a memory to store some or all of the teletext pages as they are broadcast. For this reason, some pages are broadcast more than once in each cycle, Teletext is used for carrying special packets interpreted by TVs and video recorders, containing information about channels, etc. Transmitting and displaying subtitles was relatively easy and it requires limited bandwidth, at a rate of perhaps a few words per second. However, it was found that by combining even a slow data rate with a memory, whole pages of information could be sent. In the early 1970s work was in progress in Britain to develop such a system, the goal was to provide UK rural homes with electronic hardware that could download pages of up-to-date news, reports and figures targeting U. K. agriculture. The original idea was the brainchild of Philips Laboratories in 1970, in 1971, CAL engineer John Adams created a design and proposal for UK broadcasters. A major objective for Adams during the development stage was to make Teletext affordable to the home user.
In reality, there was no scope to make an economic Teletext system with 1971 technology, however, as low cost was essential to the projects long term success, this obstacle had to be overcome. Meanwhile, the General Post Office, whose telecommunications division became British Telecom, had been researching a similar concept since the late 1960s, unlike Teledata which was a one-way service carried in the existing TV signal, Viewdata was a two-way system using telephones. Since the Post Office owned the telephones, this was considered to be an excellent way to more customers to use the phones. In 1972 the BBC demonstrated their system, now known as Ceefax, the Independent Television Authority announced their own service in 1973, known as ORACLE
Digital television is the transmission of audio and video by digitally processed and multiplexed signal, in contrast to the totally analog and channel separated signals used by analog television. Digital TV can support more than one program in the channel bandwidth. It is a service that represents the first significant evolution in television technology since color television in the 1950s. Several regions of the world are in different stages of adaptation and are implementing different broadcasting standards and this standard has been adopted in Europe, Singapore and New Zealand. Advanced Television System Committee uses eight-level vestigial sideband for terrestrial broadcasting and this standard has been adopted by six countries, United States, Mexico, South Korea, Dominican Republic and Honduras. Integrated Services Digital Broadcasting is a designed to provide good reception to fixed receivers. It utilizes OFDM and two-dimensional interleaving and it supports hierarchical transmission of up to three layers and uses MPEG-2 video and Advanced Audio Coding.
This standard has adopted in Japan and the Philippines. ISDB-T International is an adaptation of this standard using H. 264/MPEG-4 AVC that been adopted in most of South America and is being embraced by Portuguese-speaking African countries. Digital Terrestrial Multimedia Broadcasting adopts time-domain synchronous OFDM technology with a signal frame to serve as the guard interval of the OFDM block. The DTMB standard has adopted in the Peoples Republic of China, including Hong Kong. Digital TVs roots have been tied very closely to the availability of inexpensive and it wasnt until the 1990s that digital TV became a real possibility. S. Until June 1990, the Japanese MUSE standard—based on an analog system—was the front-runner among the more than 23 different technical concepts under consideration, then, an American company, General Instrument, demonstrated the feasibility of a digital television signal. This breakthrough was of significance that the FCC was persuaded to delay its decision on an ATV standard until a digitally based standard could be developed.
In March 1990, when it became clear that a standard was feasible. The new ATV standard allowed the new DTV signal to be based on new design principles. Although incompatible with the existing NTSC standard, the new DTV standard would be able to incorporate many improvements, the final standard adopted by the FCC did not require a single standard for scanning formats, aspect ratios, or lines of resolution. This outcome resulted from a dispute between the electronics industry and the computer industry over which of the two scanning processes—interlaced or progressive—is superior
A color space is a specific organization of colors. In combination with physical device profiling, it allows for reproducible representations of color, for example, Adobe RGB and sRGB are two different absolute color spaces, both based on the RGB color model. When defining a color space, the reference standard is the CIELAB or CIEXYZ color spaces. For example, although several specific color spaces are based on the RGB color model, colors can be created in printing with color spaces based on the CMYK color model, using the subtractive primary colors of pigment. The resulting 3-D space provides a position for every possible color that can be created by combining those three pigments. Colors can be created on computer monitors with color spaces based on the RGB color model, a three-dimensional representation would assign each of the three colors to the X, Y, and Z axes. Note that colors generated on given monitor will be limited by the medium, such as the phosphor or filters. Another way of creating colors on a monitor is with an HSL or HSV color space, based on hue, with such a space, the variables are assigned to cylindrical coordinates.
Many color spaces can be represented as three-dimensional values in this manner, but some have more, or fewer dimensions, Color space conversion is the translation of the representation of a color from one basis to another. The RGB color model is implemented in different ways, depending on the capabilities of the system used, by far the most common general-used incarnation as of 2006 is the 24-bit implementation, with 8 bits, or 256 discrete levels of color per channel. Any color space based on such a 24-bit RGB model is limited to a range of 256×256×256 ≈16.7 million colors. Some implementations use 16 bits per component for 48 bits total and this is especially important when working with wide-gamut color spaces, or when a large number of digital filtering algorithms are used consecutively. The same principle applies for any color space based on the color model. CIE1931 XYZ color space was one of the first attempts to produce a space based on measurements of human color perception. The CIERGB color space is a companion of CIE XYZ.
Additional derivatives of CIE XYZ include the CIELUV, CIEUVW, RGB uses additive color mixing, because it describes what kind of light needs to be emitted to produce a given color. RGB stores individual values for red and blue, RGBA is RGB with an additional channel, alpha, to indicate transparency. Common color spaces based on the RGB model include sRGB, Adobe RGB, ProPhoto RGB, scRGB, one starts with a white substrate, and uses ink to subtract color from white to create an image
Telecine is the process of transferring motion picture film into video and is performed in a color suite. The term is used to refer to the equipment used in the post-production process. Telecine enables a motion picture, captured originally on film stock, to be viewed with standard equipment, such as television sets, video cassette recorders, DVD. Within the film industry, it is referred to as a TK. With the advent of popular broadcast television, producers realized they needed more than live television programming, the difference in frame rates between film and television meant that simply playing a film into a television camera would result in flickering. Originally the kinescope was used to record the image from a display to film. This could be re-played directly into a camera for re-display. Non-live programming could be filmed using the cameras, edited mechanically as normal. As the film was run at the speed as the television. Color was supported by using a video camera, prisms. However, this still left film shot at cinema frame rates as a problem, the obvious solution is to simply speed up the film to match the television frame rates, but this, at least in the case of NTSC, is rather obvious to the eye and ear.
This problem is not difficult to fix, the solution being to play a selected frame twice. For NTSC, the difference in rates can be corrected by showing every fourth frame of film twice. A more convincing technique is to use 2,3 pulldown, discussed below, PAL uses a similar system,2,2 pulldown. In recent decades, telecine has primarily been a film-to-videotape process, changes since the 1950s have primarily been in terms of equipment and physical formats, the basic concept remains the same. Home movies are video tapes of films that used this technique, the most complex part of telecine is the synchronization of the mechanical film motion and the electronic video signal. Every time the part of the telecine samples the light electronically. This is relatively easy when the film is photographed at the frame rate as the video camera will sample, but when this is not true
DVD is a digital optical disc storage format invented and developed by Philips, Sony and Panasonic in 1995. The medium can store any kind of data and is widely used for software. DVDs offer higher capacity than compact discs while having the same dimensions. Pre-recorded DVDs are mass-produced using molding machines that physically stamp data onto the DVD, such discs are a form of DVD-ROM because data can only be read and not written or erased. Blank recordable DVD discs can be recorded using a DVD recorder. Rewritable DVDs can be recorded and erased many times, DVDs containing other types of information may be referred to as DVD data discs. The OED states that in 1995, The companies said the name of the format will simply be DVD. Toshiba had been using the name ‘digital video disk’, but that was switched to ‘digital versatile disk’ after computer companies complained that it left out their applications, Digital versatile disc is the explanation provided in a DVD Forum Primer from 2000 and in the DVD Forums mission statement.
There were several formats developed for recording video on optical discs before the DVD, Optical recording technology was invented by David Paul Gregg and James Russell in 1958 and first patented in 1961. A consumer optical disc data format known as LaserDisc was developed in the United States and it used much larger discs than the formats. CD Video used analog video encoding on optical discs matching the established standard 120 mm size of audio CDs, Video CD became one of the first formats for distributing digitally encoded films in this format, in 1993. In the same year, two new optical disc formats were being developed. By the time of the launches for both formats in January 1995, the MMCD nomenclature had been dropped, and Philips and Sony were referring to their format as Digital Video Disc. Representatives from the SD camp asked IBM for advice on the system to use for their disc. Alan E. Bell, a researcher from IBMs Almaden Research Center, got that request and this group was referred to as the Technical Working Group, or TWG.
On August 14,1995, an ad hoc group formed from five computer companies issued a release stating that they would only accept a single format. The TWG voted to both formats unless the two camps agreed on a single, converged standard. They recruited Lou Gerstner, president of IBM, to pressure the executives of the warring factions, as a result, the DVD specification provided a storage capacity of 4.7 GB for a single-layered, single-sided disc and 8.5 GB for a dual-layered, single-sided disc
Video scalers are typically found inside consumer electronics devices such as televisions, video game consoles, and DVD or Blu-ray disc players, but can be found in other AV equipment. Video scalers can be a completely separate devices, often providing simple video switching capabilities and 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 processor that improves the apparent definition of video signals. Video scalers are primarily a device, they can be combined with an analog-to-digital converter. The native resolution of a display is how many physical pixels make up each row, there are many different video signals in use which are not the same resolution, 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, multiple common resolutions are used for high-definition television, 720p, 1080i, and 1080p.
When the U. S. cable network TNT introduced an HD feed in 2004, 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 vice president of broadcast engineering at TNT. Despite TNTs intentions, the system was criticized by viewers of high definition channels. In 2014, FXX faced similar criticism for its use of cropping and scaling on reruns of The Simpsons, 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. Display resolution Deinterlacing Dither Image rescaling Video display standards DVD recorder
The cent is a logarithmic unit of measure used for musical intervals. Twelve-tone equal temperament divides the octave into 12 semitones of 100 cents each, alexander J. Ellis based the measure on the acoustic logarithms decimal semitone system developed by Gaspard de Prony in the 1830s, at Robert Holford Macdowell Bosanquets suggestion. It has become the method of representing and comparing musical pitches. Like a decibels relation to intensity, a cent is a ratio between two close frequencies, for the ratio to remain constant over the frequency spectrum, the frequency range encompassed by a cent must be proportional to the two frequencies. An equally tempered semitone spans 100 cents by definition, an octave—two notes that have a frequency ratio of 2, 1—spans twelve semitones and therefore 1200 cents.0005777895. For example, in just intonation the major third is represented by the frequency ratio 5,4, applying the formula at the top shows that this is about 386 cents. The equivalent interval on the piano would be 400 cents.
The difference,14 cents, is about a seventh of a half step, as x increases from 0 to 1⁄12, the function 2x increases almost linearly from 1.00000 to 1.05946. The exponential cent scale can therefore be accurately approximated as a linear function that is numerically correct at semitones. That is, n cents for n from 0 to 100 may be approximated as 1 +0. 0005946n instead of 2 n⁄1200. The rounded error is zero when n is 0 or 100, and is about 0.72 cents high when n is 50 and this error is well below anything humanly audible, making this piecewise linear approximation adequate for most practical purposes. It is difficult to establish how many cents are perceptible to humans, one author stated that humans can distinguish a difference in pitch of about 5–6 cents. The threshold of what is perceptible, technically known as the just noticeable difference, varies as a function of the frequency, the amplitude and the timbre. In one study, changes in tone quality reduced student musicians ability to recognize, as out-of-tune and it has been established that increased tonal context enables listeners to judge pitch more accurately.
Free, online web sites for self-testing are available, while intervals of less than a few cents are imperceptible to the human ear in a melodic context, in harmony very small changes can cause large changes in beats and roughness of chords. When listening to pitches with vibrato, there is evidence that humans perceive the mean frequency as the center of the pitch, normal adults are able to recognize pitch differences of as small as 25 cents very reliably. Adults with amusia, have trouble recognizing differences of less than 100 cents, iring noticed that the Grad/Werckmeister and the schisma are nearly the same and both may be approximated by 600 steps per octave. Yasser promoted the decitone and millitone, for example, Equal tempered perfect fifth =700 cents =175.6 savarts =583.3 millioctaves =350 centitones
Frequency is a 2000 American science fiction thriller drama film. It was co-produced and directed by Gregory Hoblit and written and co-produced by Toby Emmerich, the film stars Dennis Quaid and Jim Caviezel as father and son and John Sullivan respectively. It was filmed in Toronto and New York City, the film gained mostly favorable reviews following its release via DVD format on October 31,2000. In October 1969, firefighter Frank Sullivan dies in a fire, leaving behind his wife Julia. Thirty years later, in 1999, now an NYPD detective, is dumped by his girlfriend Samantha for refusing to move out of his fathers house. Johns childhood friend Gordo finds a Heathkit single-sideband ham radio that once belonged to Frank, eventually, he realizes that the other man is Frank and tries to warn him of his impending death. The next day, while attempting to rescue a girl, Frank heeds his sons warning. That evening, the two reconnect and learn a great deal about each others lives, Satch DeLeon, assigns him to investigate the Nightingale, a serial killer who murdered three nurses in the 1960s.
However, John discovers that the Nightingale is now connected to ten murders, feeling guilty that their actions somehow led to the Nightingale committing more murders, John persuades his father to help him prevent these crimes from occurring. Frank manages to save the first victim, but when he tries to rescue the second, the Nightingale subdues him, steals his drivers license, and plants it on the victim to frame Frank for the murder. When Frank shares his experience with his son, John realizes Franks wallet has the Nightingales fingerprints, John instructs his father to wrap his wallet in plastic and hide it somewhere in the house where John can find it 30 years later. Using the preserved fingerprints from the wallet, John identifies the Nightingale as Jack Shepard, in the original timeline, Shepard died from a medical error the same night Frank died. But since, in the new timeline, Julia didnt leave the hospital early after learning of Franks death, she was at the hospital, Frank is approached by then-Detective Satch DeLeon who tries to arrest him on suspicion of murder.
In the resulting struggle, the radio is knocked over and sustains damage, while awaiting questioning, Frank activates the precincts fire sprinkler system and breaks into Shepards apartment, where he finds jewelry taken from the victims. Shepard catches Frank in the act and pursues him, ending with a fight underwater where Frank appears to have killed Shepard, Frank fixes the radio, but while talking both he and John are attacked by the 1969 and 1999 versions of Shepard. Using a shotgun, Frank manages to blow off Shepards right hand in 1969, the timeline rapidly fixes itself in 1999 and an elderly Frank kills Shepard and embraces his son. The film concludes with a baseball game including John, Johns young son, Julia and Gordo, sylvester Stallone was rumored to be taking the role of Frank Sullivan in 1997, but fell out of the deal after a dispute over his fee. Renny Harlin was rumored to be director on the film, Gregory Hoblit first read the script in November 1997, eighteen months after his fathers death
The refresh rate is the number of times in a second that a display hardware updates its buffer. For example, most movie projectors advance from one frame to the next one 24 times each second, but each frame is illuminated two or three times before the next frame is projected using a shutter in front of its lamp. As a result, the movie runs at 24 frames per second. On cathode ray tube displays, increasing the rate decreases flickering. However, if a refresh rate is specified that is beyond what is recommended for the display, for computer programs or telemetry, the term is applied to how frequently a datum is updated with a new external value from another source. It is limited by the maximum horizontal scan rate and the resolution. The refresh rate can be calculated from the scan rate by dividing the scanning frequency by the number of horizontal lines multiplied by 1.05. For instance, a monitor with a horizontal scanning frequency of 96 kHz at a resolution of 1280 ×1024 results in a rate of 96,000 ÷ ≈89 Hz. CRT refresh rates have historically been an important factor in game programming.
Traditionally, one of the principles of game programming is to avoid altering the computers video buffer except during the vertical retrace. This is necessary to prevent flickering graphics or screen tearing, some video game consoles such as the Famicom/Nintendo Entertainment System did not allow any graphics changes except during the retrace. Contrary to popular belief, liquid-crystal displays do suffer from flickering problems and it is still necessary to avoid modifying graphics data except during the retrace phase to prevent tearing from an image that is rendered faster than the display operates. CRTs have the ability to use light guns and pens. These are devices with a photosensor that detects the electron beam and this can be used to determine if a specific graphics object is on the screen. The light gun is a variant used in arcade games. Unlike light pens, they are held at a distance from the screen, light pens and guns cannot be used on fixed-pixel displays because they have no electron beam to detect.
Pen tablets and touchscreen LCDs are used as a substitute for them, the Nintendo DS is an example of a video game system that has a touchscreen LCD. Refresh rate or the resolution of an LCD is the number of times per second in which the display draws the data it is being given
From just 30 in Q32015, the forum published a list up to 55 commercial services available around the world offering 4K resolution. Ultra-high-definition television is known as Ultra HD, UHD, in Japan, 8K UHDTV will be known as Super Hi-Vision since Hi-Vision was the term used in Japan for HDTV. In the consumer electronics market companies had only used the term 4K at the 2012 CES. Two resolutions are defined as UHDTV, 4K UHDTV is 3840 pixels wide by 2160 pixels tall, NHK advocates the 8K UHDTV format with 22.2 surround sound as Super Hi-Vision. The human visual system has an ability to discern improvements in resolution when picture elements are already small enough or distant enough from the viewer. UHDTV, allows other image enhancements than pixel density, dynamic range and color are greatly enhanced, and these impact saturation and contrast differences that are readily resolved and greatly improve the experience of 4KTV compared to HDTV. UHDTV allows the use of the new Rec.2020 color space which can reproduce colors that cannot be shown with the current Rec.709 color space.
UHDTVs increases in dynamic range allow not only brighter highlights but increased detail in the greyscale, UHDTV allows for frame rates up to 120 frames per second. 2020, higher range, and higher frame rates to work on HD services without increasing resolution to 4K. NHK researchers built a UHDTV prototype which they demonstrated in 2003 and they used an array of 16 HDTV recorders with a total capacity of almost 3.5 TB that could capture up to 18 minutes of test footage. The camera itself was built with four 2.5 inch CCDs, using two CCDs for green and one each for red and blue, they used a spatial pixel offset method to bring it to 7680x4320. A review of the NAB2006 demo was published in a Broadcast Engineering e-newsletter, individuals at NHK and elsewhere project that the timeframe for UHDTV to be available in domestic homes varies between 2015 and 2020 but Japan may get it in the 2016 time frame. On November 2,2006, NHK demonstrated a live relay of a UHDTV program over a 260 kilometer distance by a fiber-optic network, using dense wavelength division multiplex, 24 Gbit/s speed was achieved with a total of 16 different wavelength signals.
On December 31,2006, NHK demonstrated a live relay of their annual Kōhaku Uta Gassen over IP from Tokyo to a 450 in screen in Osaka. Using a codec developed by NHK, the video was compressed from 24 Gbit/s to 180–600 Mbit/s, uncompressed, a 20-minute broadcast would require roughly 4 TB of storage. The SMPTE first released Standard 2036 for UHDTV in 2007, UHDTV was defined as having two levels called UHDTV1 and UHDTV2. In May 2007, the NHK did a demonstration at the NHK Open House in which a UHDTV signal was compressed to a 250 Mbit/s MPEG2 stream. The signal was input to a 300 MHz wide band modulator and this on the air transmission had a very limited range, but shows the feasibility of a satellite transmission in the 36,000 km orbit