CCIR System B
CCIR System B was the 625-line analog broadcast television system which at its peak was the system used in the most countries. It is being replaced across Western Europe, part of Asia, the system was developed for VHF band Some of the important specs are listed below. A frame is the total picture, the frame rate is the number of pictures displayed in one second. But each frame is scanned twice interleaving odd and even lines. Each scan is known as a field So field rate is twice the frame rate, in each frame there are 625 lines So line rate is 625 times the frame frequency or 625•25=15625 Hz. The video bandwidth is 5.0 MHz, the video signal modulates the carrier by Amplitude Modulation. But a portion of the side band is suppressed. This technique is known as vestigial side band modulation, the polarity of modulation is negative, meaning that an increase in the instantaneous brightness of the video signal results in a decrease in RF power and vice versa. Specifically, the sync pulses result in power from the transmitter.
The primary audio signal is modulated by Frequency modulation with a time constant of τ =50 μs. The deviation for a 1.0 kHz, the separation between the primary audio FM subcarrier and the video carrier is 5.5 MHz. In specs, other such as vestigial sideband characteristics. System B has variously been used both the PAL or SECAM colour systems. It could have used with a 625-line variant of the NTSC color system, but apart from possible technical tests in the 1950s. When used with PAL, the subcarrier is 4.43361875 MHz. On the low-frequency side, the full 1.3 MHz sideband is radiated, when used with SECAM, the R lines carrier is at 4.40625 MHz deviating from +350±18 kHz to -506±25 kHz. The B lines carrier is at 4.250 MHz deviating +506±25 kHz to -350±18 kHz, neither colour encoding system has any effect on the bandwidth of system B as a whole. Enhancements have been made to the specification of System Bs audio capabilities over the years, the introduction of Zweiton in the 1970s allowed for stereo sound or twin monophonic audio tracks
Super Nintendo Entertainment System
In Japan, the system is called the Super Famicom, or SFC for short. In South Korea, it is known as the Super Comboy and was distributed by Hyundai Electronics, although each version is essentially the same, several forms of regional lockout prevent the different versions from being compatible with one another. It was released in Brazil on September 2,1992, by Playtronic, the SNES is Nintendos second home console, following the Nintendo Entertainment System. The console introduced advanced graphics and sound compared with other systems at the time. The development of a variety of enhancement chips integrated in game cartridges helped to keep it competitive in the marketplace. The SNES remained popular well into the 32-bit era, and continues to be popular among fans, retro gamers, and emulation enthusiasts, some of whom still make homebrew ROM images. To compete with the popular Family Computer in Japan, NEC Home Electronics launched the PC Engine in 1987, the two platforms were launched in North America in 1989 as the TurboGrafx-16 and the Genesis respectively.
Both systems were built on 16-bit architectures and offered improved graphics, however, it took several years for Segas system to become successful. Nintendo executives were in no rush to design a new system, designed by Masayuki Uemura, the designer of the original Famicom, the Super Famicom was released in Japan on Wednesday, November 21,1990 for 25,000 yen. The systems release gained the attention of the Yakuza, leading to a decision to ship the devices at night to avoid robbery, with the Super Famicom quickly outselling its chief rivals, Nintendo reasserted itself as the leader of the Japanese console market. Nintendos success was due to its retention of most of its key third-party developers from its earlier system, including Capcom, Tecmo, Koei. Nintendo released the Super Nintendo Entertainment System, a version of the Super Famicom. It began shipping in limited quantities on August 23,1991, the SNES was released in the United Kingdom and Ireland in April 1992 for £150, with a German release following a few weeks later.
Most of the PAL region versions of the use the Japanese Super Famicom design, except for labeling. The Playtronic Super NES in Brazil, although PAL, uses the North American design, both the NES and SNES were released in Brazil in 1993 by Playtronic, a joint venture between the toy company Estrela and consumer electronics company Gradiente. The SNES and Super Famicom launched with few games, but these games were received in the marketplace. In Japan, only two games were available, Super Mario World and F-Zero. In North America, Super Mario World launched as a bundle with the console, and other titles include F-Zero, SimCity
180-line television system
180 lines is an early electronic television system. It was used in Germany after on March 22,1935, using telecine transmission of film, intermediate film system, transmissions using cameras based on the iconoscope began on January 15,1936. The Berlin Summer Olympic Games were televised, using both fully electronic iconoscope-based cameras and intermediate film cameras, to Berlin and Hamburg in August 1936, twenty-eight public television rooms were opened for anybody who did not own a television set. After February 1937 this system was replaced by a superior 441-line system
Safe area (television)
Safe area is a term used in television production to describe the areas of the television picture that can be seen on television screens. Older televisions can display less of the space outside of the area than ones made more recently. Flat panel screens, Plasma displays and liquid crystal display screens generally can show most of the picture outside the safe areas, the use of safe areas in television production ensures that the most important parts of the picture are seen by the majority of viewers. The size of the area is typically specified in pixels or percent. The NTSC and PAL analog television standards do not specify official overscan amounts and this is applied against a worst case of on-screen location and display type. Typically corners would require more space from the edges, but due to increased quality of the average display this is no longer the concern it used to be, even on CRTs. If the editor of the content does not take care to ensure that all titles are inside the title-safe area, video editing programs that can output video for either television or the Web can take the title-safe area into account.
Final Cut Pro can show two overlay rectangles in both its Viewer and Canvas, the rectangle is the title-safe area and the outer rectangle is the action-safe area. In the illustration, the area is referred to as the title-safe area. This area will be seen by all television screens, no matter when they were made, the term title-safe originated from the fact this is where it is safe to display text such as lower thirds or full-screen graphics listing information such as telephone numbers. Depending on how a set is adjusted, viewers can see a larger area than the title-safe area. The action-safe area is a rectangle, consisting of the green title-safe area. As of 2007, most television stations and networks will place information within this area, if the station uses a permanent digital on-screen graphic, it is placed just near the corner of the yellow area. However, the area might be used if the television station wants the information to block against the edge of the screen. Many stations place tickers that run horizontally in some of the yellow area, action-safe area is applied against a worst case of on-screen location and display type.
The red border in the illustration represents the overscan, the area of the picture outside the action-safe area. It is not shown on most consumer television screens, unless the user modifies the televisions settings and it is generally considered safe to have elements that shouldnt be seen by the viewers placed in this area, such as the edge of the set or cables and other equipment. Television stations generally have professional-grade monitors that can be put into underscan mode and these monitors often include white lines showing where the title-safe and safe areas are located
CCIR System I
CCIR System I is an analog broadcast television system. The UK started its own 625-line television service in 1964 using System I, since then, System I has been adopted for use by Hong Kong, the Falkland Islands and South Africa. The Republic of Ireland has extended its use of System I onto the UHF bands, as of late 2012, analog television is no longer transmitted in either the UK or the Republic of Ireland. South Africa expects to discontinue System I in 2013, and Hong Kong by 2015, some of the important specs are listed below. A frame is the total picture, the frame rate is the number of pictures displayed in one second. But each frame is scanned twice interleaving odd and even lines. Each scan is known as a field So field rate is twice the frame rate, in each frame there are 625 lines So line rate is 625 times the frame frequency or 625•25=15625 Hz. The total RF bandwidth of System I was about 7.4 MHz, in specs, other parameters such as vestigial sideband characteristics and gamma of display device are given.
System I has only used with the PAL colour systems. However, apart from possible technical tests in the 1960s, this has never been done officially, when used with PAL, the colour subcarrier is 4.43361875 MHz and the sidebands of the PAL signal have to be truncated on the high-frequency side at +1.066 MHz. On the low-frequency side, the full 1.3 MHz sideband width is radiated.0 MHz to 5.9996 MHz and this is such a slight frequency shift that no alterations needed to be made to existing System I television sets when the change was made. No colour encoding system has any effect on the bandwidth of system I as a whole, enhancements have been made to the specification of System Is audio capabilities over the years. Starting in the late 1980s and early 1990s it became possible to add a digital signal carrying NICAM sound, good channel planning means that under normal situations no ill effects are seen or heard. The NICAM system used with System I adds a 700 kHz wide digital signal, VHF Band 1 was already discontinued for TV broadcasting well before Irelands digital switchover.
♥ No longer used for TV broadcasting, UHF takeup in Ireland was slower than in the UK. A written answer in the Dáil Éireann shows that even by mid 1988 Ireland was only transmitting on UHF from four main transmitters and 11 relays, † Officially these channels dont exist, being between UHF Band IV and Band V and were supposed to be reserved for radio astronomy. However, from 1997 until the finish of analog TV in the UK in 2012, § Allocated, but never used in the UK. Broadcast television systems Television transmitter Transposer World Analogue Television Standards and Waveforms Fernsehnormen aller Staaten und Gebiete der Welt
Overscan is the situation in which not all of a televised image is present on a viewing screen. It exists because cathode-ray tube television sets from the 1930s through to the early 2000s were highly variable in how the image was positioned within the borders of the screen. The solution was to have the show less than the full image. Early analogue televisions varied in the image because of manufacturing tolerance problems. There were effects from the design limitations of power supplies. Because of this, TV producers could not be certain where the edges of the image would be. In order to compensate, they defined three areas, Title safe, An area visible by all reasonably maintained sets, where text was not to be cut off. Action safe, A larger area that represented where a set would cut the image off. Underscan, The full image area to the edge of the signal. Studio monitors and camera viewfinders were set to show this area, when used, this mode is called underscan. Todays TV sets are based on newer fixed-pixel technology like liquid crystal displays, as overscan reduces picture quality, it is undesirable for 1080i and 1080p sets, therefore,1,1 pixel mapping is preferred.
On LCDs driven from a signal, no adjustment is necessary because all pixels are in fixed positions. Thus all modern computers can safely assume that all pixels are visible to the viewer, analog video signals such as VGA, are subject to timing variations and even when using an LCD panel do not have this exactness. When video or animation content is designed to be viewed on computers, CRTs made for computer display are set to underscan with an adjustable border, usually colored black. The border will change size and shape if required to allow for the tolerance of low precision, as such, computer CRTs use less physical screen area than TVs, to allow all information to be shown at all times. Computer CRT monitors usually have a black border —these can be seen in the video card timings, video game systems have been designed to keep important game action in the title safe area. Older systems did this with borders for example, the Super Nintendo Entertainment System windowboxed the image with a border, visible on some NTSC television sets.
Newer systems frame content much as live action does, with the area filled with extraneous details
Raster bar-style effects were common on the Atari 2600 and Atari 8-bit family and later in demos for the Commodore 64, Atari ST, ZX Spectrum and Amstrad CPC. The term copperbar comes from a coprocessor on the Amiga home computer referred to as the Copper. It can be programmed to change the display colors per scan line without requiring the CPU, by using multiple colours in succession and carefully gradating the changes, an effect of metallic-looking horizontal bars can be achieved. A similar effect can be generated vertically, although it often does not extend into the border area, to generate vertical bars, the same line of video memory is repeatedly output every scanline. At the top of the frame, the memory is typically blank. Vertical raster bars are sometimes called Kefrens bars, after the Amiga demo group that popularized them, the effect was implemented earlier by the Alcatraz demo group. Rasterbars in 16 bytes Various Rasterbar effects
405-line television system
The 405-line monochrome analogue television broadcasting system was the first fully electronic television system to be used in regular broadcasting. It was introduced with the BBC Television Service in 1936, suspended for the duration of World War II and it was used between 1961 and 1982 in Ireland, as well as from 1957 to 1973 for the Rediffusion Television cable service in Hong Kong. Sometimes called the Marconi-EMI system, it was developed in 1934 by the EMI Research Team led by Sir Isaac Shoenberg, the figure of 405 lines had been chosen following discussions over Sunday lunch at the home of Alan Blumlein. The system used interlacing, EMI had been experimenting with a 243 line all-electronic interlaced system since 1933, in the 405 system the scanning lines were broadcast in two complementary fields,50 times per second, creating 25 frames per second. At the time of its introduction the 405-line system was referred to as high definition, in 1934 the British government set up a committee to advise on the future of TV broadcasting.
The committee recommended that a high service to be run by the BBC be established. The recommendation was accepted and tenders were sought from industry, two tenders were received, one from the Baird company offering a 240 line mechanical system, and the other from EMI offering a 405-line all-electronic one. The Television Committee advised that they were unable to choose between the two systems and that both tenders should be accepted, the two systems to be run together for an experimental period and this became the standard for all British TV broadcasts until the 1960s. It soon became apparent that television reception was well outside the original intended service area. A few minutes of programming were recorded on 16 mm movie film and this is now considered to be the only surviving example of pre-war, live British television. The BBC temporarily ceased transmissions on 1 September 1939, the day of the German invasion of Poland, in 1954 the BBC lost its monopoly of the British television market, and the following year the commercial network ITV, comprising a consortium of regional companies, was launched.
In 1964 the BBC launched its BBC2 service on UHF using only a 625-line system, the introduction of colour on BBC2 in 1967 necessitated an even more complex dual-standard set to receive all three channels. In November 1969 BBC1 and ITV started broadcasting in 625-line PAL colour on UHF, as their programming was now entirely produced using the new standard, the 405-line broadcasts served only as a rebroadcast in monochrome for people who did not have the newer receivers. Thereafter, receivers were of a single standard design which could not receive the legacy 405 line transmissions. The last 405-line transmissions were seen on 3 January 1985, in Scotland and this left only the UHF PAL system in operation in the UK. The frequencies used by the 405-line system were left empty. This was because people in these areas already had 405-line sets for receiving UK broadcasts from Wales or Northern Ireland. Telefís Éireanns primary standard was 625-line which began in the summer of 1962, the service of 405-line system ended in 1973, replaced by 625-line PAL system free-to-air broadcast
Texture mapping is a method for defining high frequency detail, surface texture, or color information on a computer-generated graphic or 3D model. Its application to 3D graphics was pioneered by Edwin Catmull in 1974, texture mapping originally referred to a method that simply wrapped and mapped pixels from a texture to a 3D surface. A texture map is an image applied to the surface of a shape or polygon and this may be a bitmap image or a procedural texture. They may be stored in image file formats, referenced by 3d model formats or material definitions. They may have 1-3 dimensions, although 2 dimensions are most common for visible surfaces, for use with modern hardware, texture map data may be stored in swizzled or tiled orderings to improve cache coherency. Rendering APIs typically manage texture map resources as buffers or surfaces and they usually contain RGB color data, and sometimes an additional channel for alpha blending especially for billboards and decal overlay textures. It is possible to use the channel for other uses such as specularity.
Multiple texture maps may be combined for control over specularity, displacement, multiple texture images may be combined in texture atlases or array textures to reduce state changes for modern hardware. Modern hardware often supports cube map textures with multiple faces for environment mapping and they may be acquired by scanning/digital photography, authored in image manipulation software such as Photoshop, or painted onto 3D surfaces directly in a 3D paint tool such as Mudbox or zbrush. This process is akin to applying patterned paper to a white box. Every vertex in a polygon is assigned a texture coordinate and this may be done through explicit assignment of vertex attributes, manually edited in a 3D modelling package through UV unwrapping tools. It is possible to associate a procedural transformation from 3d space to space with the material. This might be accomplished via planar projection or, cylindrical or spherical mapping, more complex mappings may consider the distance along a surface to minimize distortion.
These coordinates are interpolated across the faces of polygons to sample the texture map during rendering, UV unwrapping tools typically provide a view in texture space for manual editing of texture coordinates. Some rendering techniques such as subsurface scattering may be performed approximately by texture-space operations, multitexturing is the use of more than one texture at a time on a polygon. For instance, a light map texture may be used to light a surface as an alternative to recalculating that lighting every time the surface is rendered. Microtextures or detail textures are used to add higher frequency details, and dirt maps may add weathering and variation, modern graphics may use in excess of 10 layers for greater fidelity which are combined using shaders. Bump mapping has become popular in recent video games, as graphics hardware has become powerful enough to accommodate it in real-time, the way that samples are calculated from the texels is governed by texture filtering
The first NTSC standard was developed in 1941 and had no provision for color. In 1953 a second NTSC standard was adopted, which allowed for television broadcasting which was compatible with the existing stock of black-and-white receivers. NTSC was the first widely adopted broadcast color system and remained dominant until 1997, North America, parts of Central America, and South Korea are adopting or have adopted the ATSC standards, while other countries are adopting or have adopted other standards instead of ATSC. After nearly 70 years, the majority of over-the-air NTSC transmissions in the United States ceased on January 1,2010, the majority of NTSC transmissions ended in Japan on July 24,2011, with the Japanese prefectures of Iwate and Fukushima ending the next year. In March 1941, the committee issued a standard for black-and-white television that built upon a 1936 recommendation made by the Radio Manufacturers Association. Technical advancements of the side band technique allowed for the opportunity to increase the image resolution.
The NTSC selected 525 scan lines as a compromise between RCAs 441-scan line standard and Philcos and DuMonts desire to increase the number of lines to between 605 and 800. The standard recommended a frame rate of 30 frames per second, other standards in the final recommendation were an aspect ratio of 4,3, and frequency modulation for the sound signal. In January 1950, the committee was reconstituted to standardize color television, in December 1953, it unanimously approved what is now called the NTSC color television standard. The compatible color standard retained full backward compatibility with existing black-and-white television sets, Color information was added to the black-and-white image by introducing a color subcarrier of precisely 315/88 MHz. These changes amounted to 0.1 percent and were tolerated by existing television receivers. The FCC had briefly approved a different color standard, starting in October 1950. However, this standard was incompatible with black-and-white broadcasts and it used a rotating color wheel, reduced the number of scan lines from 525 to 405, and increased the field rate from 60 to 144, but had an effective frame rate of only 24 frames per second.
CBS rescinded its system in March 1953, and the FCC replaced it on December 17,1953, with the NTSC color standard, that year, the improved TK-41 became the standard camera used throughout much of the 1960s. The NTSC standard has been adopted by countries, including most of the Americas. With the advent of television, analog broadcasts are being phased out. Most US NTSC broadcasters were required by the FCC to shut down their analog transmitters in 2009, low-power stations, Class A stations and translators were required to shut down by 2015. NTSC color encoding is used with the System M television signal, each frame is composed of two fields, each consisting of 262.5 scan lines, for a total of 525 scan lines
Analog television or analogue television is the original television technology that uses analog signals to transmit video and audio. In an analog television broadcast, the brightness and sound are represented by variations of either the amplitude. Analog signals vary over a range of possible values which means that electronic noise. So with analog, a weak signal becomes snowy and subject to interference. In contrast, a moderately weak signal and a very strong digital signal transmit equal picture quality. Analog television may be wireless or can be distributed over a network using cable converters. All broadcast television systems preceding digital transmission of digital television used analog signals, analog television around the world has been in the process of shutting down since the late 2000s. The earliest systems were mechanical systems which used spinning disks with patterns of holes punched into the disc to scan an image. A similar disk reconstructed the image at the receiver, synchronization of the receiver disc rotation was handled through sync pulses broadcast with the image information.
However these mechanical systems were slow, the images were dim and flickered severely, camera systems used similar spinning discs and required intensely bright illumination of the subject for the light detector to work. Analog television did not really begin as an industry until the development of the cathode-ray tube, the electron beam could be swept across the screen much faster than any mechanical disc system, allowing for more closely spaced scan lines and much higher image resolution. Also far less maintenance was required of an all-electronic system compared to a spinning disc system, all-electronic systems became popular with households after the Second World War. Broadcasters using analog television systems encode their signal using different systems, the official systems of transmission are named, A, B, C, D, E, F, G, H, I, K, K1, L, M and N. These systems determine the number of lines, channel width, vision bandwidth, vision-sound separation, each frame of a television image is composed of lines drawn on the screen.
The lines are of varying brightness, the set of lines is drawn quickly enough that the human eye perceives it as one image. The next sequential frame is displayed, allowing the depiction of motion, the analog television signal contains timing and synchronization information, so that the receiver can reconstruct a two-dimensional moving image from a one-dimensional time-varying signal. The first commercial systems were black-and-white, the beginning of color television was in the 1950s. A practical television system needs to take luminance, chrominance and audio signals, the transmission system must include a means of television channel selection