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Tri-level Sync
Tri-level sync is an analogue video synchronization pulse primarily used for the locking of high-definition video signals (genlock). It is preferred in HD environments over black and burst, as timing jitter is reduced due to the nature of its higher frequency. It also benefits from having no DC content, as the pulses are in both polarities. Synchronization Modern real-time multi-source HD facilities have many pieces of equipment that all output HD- SDI video. If this baseband video is to be mixed, switched or luma keyed with any other sources, then they will need to be synchronous, i.e. the first pixel of the first line must be transmitted at the same time (within a few microseconds). This then allows the switcher to cut, mix or key these sources together with a minimal amount of delay (~1 HD video line 1/(1125×25) seconds for 50i video). This synchronization is done by supplying each piece of equipment with either a tri-level sync, or black-and-burst input. There are video ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tri Level Sync
Tri-level sync is an analogue video synchronization pulse primarily used for the locking of high-definition video signals (genlock). It is preferred in HD environments over black and burst, as timing jitter is reduced due to the nature of its higher frequency. It also benefits from having no DC content, as the pulses are in both polarities. Synchronization Modern real-time multi-source HD facilities have many pieces of equipment that all output HD- SDI video. If this baseband video is to be mixed, switched or luma keyed with any other sources, then they will need to be synchronous, i.e. the first pixel of the first line must be transmitted at the same time (within a few microseconds). This then allows the switcher to cut, mix or key these sources together with a minimal amount of delay (~1 HD video line 1/(1125×25) seconds for 50i video). This synchronization is done by supplying each piece of equipment with either a tri-level sync, or black-and-burst input. There are video sw ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
High-definition Video
High-definition video (HD video) is video of higher resolution and quality than standard-definition. While there is no standardized meaning for ''high-definition'', generally any video image with considerably more than 480 vertical scan lines (North America) or 576 vertical lines (Europe) is considered high-definition. 480 scan lines is generally the minimum even though the majority of systems greatly exceed that. Images of standard resolution captured at rates faster than normal (60 frames/second North America, 50 fps Europe), by a high-speed camera may be considered high-definition in some contexts. Some television series shot on high-definition video are made to look as if they have been shot on film, a technique which is often known as filmizing. History The first electronic scanning format, 405 lines, was the first ''high definition'' television system, since the mechanical systems it replaced had far fewer. From 1939, Europe and the US tried 605 and 441 lines until, in 1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genlock
Genlock (generator locking) is a common technique where the video output of one source (or a specific reference signal from a signal generator) is used to synchronize other picture sources together. The aim in video applications is to ensure the coincidence of signals in time at a combining or switching point. When video instruments are synchronized in this way, they are said to be ''generator-locked'', or ''genlocked''. Possible problems Video signals generated and output by generator-locked instruments are said to be syntonized. Syntonized video signals will be precisely frequency-locked, but because of delays caused by the unequal transmission path lengths, the synchronized signals will exhibit differing phases at various points in the television system. Modern video equipment such as production switchers that have multiple video inputs often include a variable delay on each input to compensate for the phase differences and time all the input signals to precise phase coinci ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Black And Burst
Black and burst, also known as bi-level sync and black burst, is an analogue signal used in broadcasting. It is a composite video signal with a black picture. It is a reference signal used to synchronise video equipment, in order to have them output video signals with the same timing. This allows seamless switching between two video signals. Black and burst can also be used to synchronise colour phase and provides timing accuracy in the order of tens of nanoseconds which is necessary to perform e.g. analogue video mixing. Black and burst exists for various colour TV standards, such as PAL, NTSC and SECAM. Because the black and burst signal is a normal video signal, it is transportable via normal video cables and through video distribution equipment. History Before colour TV existed, the reference signal was also a black video signal. Inaccuracies meant the video picture would be shifted. With the introduction of colour, the reference had to be much more accurate. In eve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Luma Key
Compositing is the process or technique of combining visual elements from separate sources into single images, often to create the illusion that all those elements are parts of the same scene. Live-action shooting for compositing is variously called "chroma key", "blue screen", "green screen" and other names. Today, most, though not all, compositing is achieved through digital image manipulation. Pre- digital compositing techniques, however, go back as far as the trick films of Georges Méliès in the late 19th century, and some are still in use. Basic procedure All compositing involves the replacement of selected parts of an image with other material, usually, but not always, from another image. In the digital method of compositing, software commands designate a narrowly defined color as the part of an image to be replaced. Then the software (e.g. Natron) replaces every pixel within the designated color range with a pixel from another image, aligned to appear as part of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Synchronous
Synchronization is the coordination of events to operate a system in unison. For example, the conductor of an orchestra keeps the orchestra synchronized or ''in time''. Systems that operate with all parts in synchrony are said to be synchronous or ''in sync''—and those that are not are '' asynchronous''. Today, time synchronization can occur between systems around the world through satellite navigation signals and other time and frequency transfer techniques. Navigation and railways Time-keeping and synchronization of clocks is a critical problem in long-distance ocean navigation. Before radio navigation and satellite-based navigation, navigators required accurate time in conjunction with astronomical observations to determine how far east or west their vessel traveled. The invention of an accurate marine chronometer revolutionized marine navigation. By the end of the 19th century, important ports provided time signals in the form of a signal gun, flag, or dropping time ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vision Mixer
A vision mixer is a device used to select between several different live video sources and, in some cases, compositing live video sources together to create visual effects. In most of the world, both the equipment and its operator are called a vision mixer or video mixer; however, in the United States, the equipment is called a video switcher, production switcher or video production switcher, and its operator is known as a technical director (TD). The role of the vision mixer for video is similar to what a mixing console does for audio. Typically a vision mixer would be found in a video production environment such as a production control room of a television studio, production truck or post-production facility. Capabilities and usage Besides hard cuts (switching directly between two input signals), mixers can also generate a variety of transitions, from simple dissolves to pattern wipes. Additionally, most vision mixers can perform keying operations (called mattes in t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Synchronization
Synchronization is the coordination of events to operate a system in unison. For example, the conductor of an orchestra keeps the orchestra synchronized or ''in time''. Systems that operate with all parts in synchrony are said to be synchronous or ''in sync''—and those that are not are '' asynchronous''. Today, time synchronization can occur between systems around the world through satellite navigation signals and other time and frequency transfer techniques. Navigation and railways Time-keeping and synchronization of clocks is a critical problem in long-distance ocean navigation. Before radio navigation and satellite-based navigation, navigators required accurate time in conjunction with astronomical observations to determine how far east or west their vessel traveled. The invention of an accurate marine chronometer revolutionized marine navigation. By the end of the 19th century, important ports provided time signals in the form of a signal gun, flag, or dropping time ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Film And Video Technology
A film also called a movie, motion picture, moving picture, picture, photoplay or (slang) flick is a work of visual art that simulates experiences and otherwise communicates ideas, stories, perceptions, feelings, beauty, or atmosphere through the use of moving images. These images are generally accompanied by sound and, more rarely, other sensory stimulations. The word "cinema", short for cinematography, is often used to refer to filmmaking and the film industry, and to the art form that is the result of it. Recording and transmission of film The moving images of a film are created by photographing actual scenes with a motion-picture camera, by photographing drawings or miniature models using traditional animation techniques, by means of CGI and computer animation, or by a combination of some or all of these techniques, and other visual effects. Before the introduction of digital production, series of still images were recorded on a strip of chemically sensitize ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Broadcast Engineering
Broadcast engineering is the field of electrical engineering, and now to some extent computer engineering and information technology, which deals with radio and television broadcasting. Audio engineering and RF engineering are also essential parts of broadcast engineering, being their own subsets of electrical engineering. Broadcast engineering involves both the Television studio, studio and transmitter aspects (the entire airchain), as well as remote broadcasts. Every Broadcast network, station has a broadcast engineer, though one may now serve an entire station group in a city. In small media markets the engineer may work on a contract basis for one or more stations as needed. Duties Modern duties of a broadcast engineer include maintaining broadcast automation systems for the studio and automatic transmission systems for the transmitter physical plant, plant. There are also important duties regarding Radio masts and towers, radio towers, which must be Preventive maintenanc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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