XYZ

XYZ

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X

xfr – a slang expression for transfer.

XG – Yamaha’s alternative to Roland’s GS system for enhancing the general midi protocol so as to provide additional banks of patches and further editing facilities.

XLR – three-pin plug for three-conductor “balanced” audio cable, covered by a metal sheath often found on high quality audio / video equipment, employed with high-quality microphones, mixers, and other audio equipment. Used with microphone and line level audio applications.  Has three leads, two for the signal and one for overall system grounding. XLR is often used for microphones. Also called cannon.

XLR connector – a popular type of audio connector featuring three leads  two for the signal and one for overall system grounding. a secure connector often found on high quality audio and video equipment; sometimes called a canon connector. Can also carry a 2-channel digital audio signal.

XVID – high compression, high quality, low bitrate. Variation of mpeg-4. Very good results, usually found in .avis, .mp4s, and .xvid.

x-rays – electromagnetic radiation similar to light but of shorter wavelength and capable of penetrating solids. X-rays can fog photographic film.

x setting – shutter speed setting at which flash synchronization occurs. for some manual cameras, the x setting designates the maximum shutter speed at which the camera synchronizes with flash.

x-sync – same as  x setting

xxx – an informal voluntary certificate for a pornographic film, indicating large amounts of explicit sex. Contrast with nc-17.

x-y panel–a routing switcher control panel that uses the x-y model for making crosspoint selections.

xerography – the technique using an electrostatic process to copy or transfer an image, commonly found in office copiers and used in cartoon production.

Y

y – 1. symbol for luminance, or brightness, portion of a video signal, especially component video; the complete color video signal consists of r,g,b and y.  2. the formula for deriving & from the red, green, and blue signals is 0.30 r + 0.59 g + 0.11 b. admittance, which is the reciprocal of impedance, the ease with which alternating current flows through a circuit.

ycbcr – the technical term for digital component video. The letter  y  represents the luminance (brightness) portion of the component-video signal, and  cb  and  cr  are the color-difference signals.

y/c video – a video signal, also known as s-video. Y is the luminance and C is the chrominance. Y and C are transmitted on separate synchronized conductors.  See s-video.

y to c delay – relative delay or timing of the luminance channel compared to the chrominance channel in a video system.

y, r-y, b-y – 1. color difference signal designation. y corresponds to the luminance signal, r-y corresponds to the red minus luminance signal, and b-y corresponds to the blue minus luminance signal. These signals are derived as follows y = 0.3 red + 0.59 green + 0.1 blue;  r-y = 0.7 red + 0.59 green – 0.1 blue;  b-y = 0.89 blue – 0.59 green – 0.3 red.  2. the general set of cav signals used in the PAL system as well as some encoder/decoder applications in NTSC systems. Y represents the luminance signal, r-y is the 1st color difference signal and b-y is the 2nd color difference signal. Y, u, and v are simply new names for y, r-y, and b-y.  The derivation from rgb is identical.

ypbpr  – the technical term for analog component video. the letter  Y represents the luminance (brightness) portion of the component-video signal, and  pb  and  pr  are the color-difference signals.

y, u, v – PAL luminance & color difference components. U and v are the names of the b-y and r-y color differences signals (respectively) when they are modulated onto subcarrier. Yuv is the abbreviation for the differential brightness and color signals. It is the color space used by NTSC and PAL video systems. While the “y” is the luma component, the “u” and “v” are the color difference components. Some may mistake the yuv notation for y cbcr data. Most use the yuv notation rather than y-uv or y u v . Technically correct is y u v  since all three components are derived from rgb. Yuv is also the name for some component analog interfaces of consumer equipment.

y-lead – lead split so that one source can feed two destinations. Y leads may also be used in console insert points in which case a stereo jack plug at one end of the lead id split into two monos at the other.

yarn – slang for an apocryphal story.

yellow – minus-blue additive primary used in the three-color-light process.

yellow book – see compact disc standards.

yellow filter – the most-popular colored filter used with black and white film. Since a yellow filter absorbs blue light, it provides significantly greater contrast between blue and yellow or white subjects. A yellow filter blocks UV and is useful in reducing haze, particularly in aerial or mountain photography.

yellow-green filter – highly-useful for landscapes photographed in black and white, the yellow-green (or yellowish-green, or yellow-greenish) filter only darkens blue skies, whitens clouds, and enhances green foliage.

yellow-orange filter – this filter has a stronger effect on skies than yellow filters, increasing darkness a great deal. It is also good for reducing blemishes and skin spots.

yellow signal – in telecommunications, a signal sent back in the direction of a failure, indicating that the input of a network element has failed. The yellow signal varies with the DS framing used.

Z

ZLR – Zoom Lens Reflex camera or simply a zoom reflex camera (see below)

z-buffer – an area of memory holding the depth (z) values of each surface in a 3d scene represented at each pixel location in the rendered image. Z-buffering is the management of image depth coordinates in 3d graphics, usually done in hardware, sometimes in software. It is one solution to the visibility problem, which is the problem of deciding which elements of a rendered scene are visible, and which are hidden. Z-buffering is also known as depth buffering.

z-plane – an image can be rendered with an additional plane, z-plane, to store depth information, i.e. the distance of every pixel from the camera. Z-plane image is usually an 8-bit black and white image with the hue grading from black to white with the distance. This information is often used as a mask when compositing image layers. The z-plane is sometimes incorporated in 3d graphics hardware to calculate depth cueing in real-time. It is then called z-buffering.

zebra pattern – in a video camera, striped patterns which appear in the viewfinder screen to indicate areas of the image where the video level is higher than a certain value.

zenith – a parameter of tape head alignment relating to whether or not the head is perpendicular to the tape path, and aligned so as to be in the same plane.

zero crossing – the point where a line joining the audio samples crosses the zero horizontal line; point at which a digitally encoded waveform crosses the center of its amplitude range. That’s where the polarity of an electrical or sampled signal goes from positive to negative (or the reverse) as it moves through  zero.  This offers a suitable location for meshing two sounds since the splice point levels are identical at zero volts.

zero-frame reference mark – dot which identifies the frame directly below as the zero frame specified by both the human readable key number and the machine readable bar code.

zero timing point – the point at which all video signals must be in synchronization, typically the switcher input.

zipper noise – audible steps that occur when a parameter is being varied in a digital audio processor.

zone – an adjacent or contiguous set of keys on a keyboard. Generally, a single sound or midi channel is allocated to a particular zone.

zone plate – a special video test pattern that s useful for assessing a video display s comb filter, as well as the 3:2 pulldown performance of progressive-scan DVD players and image scalers within video displays.

zone system – a method introduced by photographer Ansel Adams for determining optimal exposure and appropriate development for an individual photograph.

zoom – 1. variance of focal length, bringing subject into and out of closeup range; to gradually change the field of view of a camera lens from wide to narrow angle (zoom in) or narrow to wide angle (zoom out).  Lens capability permits change from wide-angle to telephoto, or vice versa, in one continuous move. Zoom in and zoom out are common terms. 2. The lens on a camcorder ranges from wide angle through to telephoto. Currently camcorders come with anything from a 10x to a 22x optical zoom. All camcorders also have a digital zoom which magnifies pixels.

zoom and pan – zoom increases the length of the camera lens, magnifying an aspect of a scene. The results of a zoom and a dolly are different. A dolly physically moves the camera closer to the point of interest without changing the length of the lens.  Zoom increases the size of the point of interest by increasing the lens length. Pan adjusts the focal point by pivoting the camera direction, usually slowly across a scene.

zoom happy – one who indulges in the gratification of zooming in and out to the torment of viewers. Common in home movies.

zoom lens – also called a variable focus lens. A lens in which focal length is variable, that is, focal lengths can be adjusted from wide angle to telephoto. Elements inside a zoom lens shift their positions, enabling the lens to change its focal length – in effect, providing one lens that has many focal lengths within a given range – e.g. 70mm to 200mm.  Nikon’s  Af-S Vr  Zoom-Nikkor 70-200mm f/2 is a zoom lens.

Zoom Lens Reflex camera – also known as a ZLR camera. A camera that has advanced features that are similar to an SLR (Single Lens Reflex) camera, but has a permanently fixed zoom lens instead of the ability to interchange lenses.

zoom lens – a lens with a variable focal length.

zoom ratio – range of a lens’ focal length, from most “zoomed in” field of view to most “zoomed out”, that is the ratio of the longest focal length to the shortest focal length of a zoom lens.  Expressed as a ratio of 6:1, for example, implies same lens from same distance can make same image appear six-times closer.  See focal length, zoom.

zoom reflex camera – same as a zoom lens reflex camera.

zoom shot – also zoom, zoom in, zooming, zoom back, zoom out. A shot in which the magnification of the objects by the camera’s lenses is increased (zoom in) or decreased (zoom out/back). There is a subtle difference between the results of a zoom shot and a dolly shot: in a zoom, the relative positions and sizes of all objects in the frame remains the same, whereas in a dolly shot this will change as the camera moves. Alfred Hitchcock’s much-imitated shot in Vertigo used a combination zoom in and dolly back, resulting in a dramatic change in perspective.

zoopraxis – also zoopraxis-scope. An early movie process developed by Eadweard Muybridge in the 1870’s, which involves a disk that includes serial pictures being rotated in front of a light source, to create a sense that the objects projected were moving.

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