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OEM –  Original Equipment Manufacturer. 1. a company supplying equipment to other companies in order to resell or incorporate this equipment into another product using the reseller’s brand name. 2. a company acquiring a product or component but then reusing or incorporating it into a new product with its own brand name.

.ogg – or sometimes .ogm, is a container (similar to .asf) for ogg vorbis audio which is another high compression codec.

OMF –  Open Media Framework. a file type that allows for sharing of interchangeable digital media.

OMS –  Open Music System (formerly Opcode Midi System). A real-time midi operating system for MacIntosh applications (and slated to be integrated into windows 95). OMS allows communication between different MIDI programs and hardware, so that, for example, a sequencer could interface with a librarian program to display synthesizer patch names, rather than just numbers, in the sequencer’s editing windows.

OTF – Off The Film. Some cameras’ built-in exposure meters take their readings from light reflected off the film.

objective – or object lens, object glass, objective lens or photographic objective. An optical system or device containing a combination of lenses that receive light rays from an object and form an image on the focal plane. A photographic lens is an objective one.

occlude – to block the passage of, as in “to occlude light”.

occlusion – the effect of one object in 3D space blocking another object from view.

octave  – 1. a band, or group of frequencies.The relationship of the frequencies is such that the lowest frequency is half  the highest, 200 hz – 400 hz is an octave, 4,000 hz – 8,000 hz is an octave.  2. a feast day and the seven days following it.  3. a musical interval of eight tones.  4. a rhythmic group of eight lines of verse.  An eight-line unit, which may constitute a stanza; or a section of a poem, as in the octave of a sonnet. 5. Notice that the visible band is about 1 octave, ranging from 400 to 800 nm (or 800 to 400 terahertz).

Oersted –  a unit of magnetic field strength.

off-air – 1. signals that are not currently going out to broadcast or videotape recording.   2. signals received “out of the air” from a transmitter.   3. to record signals off the air.

off book – when an actor has completely memorized their lines and cues, they are described as being off-book, no longer in need of their script.

off-line editing – 1. editing that is done using inexpensive, non-broadcast-quality equipment to produce an edit decision list (EDL) which will be used later for assembling a broadcast quality program using more expensive, high quality equipment. 2. creative assembling of elements of production to communicate the proper message, story. 3. The creative editing process which uses copies of the camera tapes on a typically “cuts only” inexpensive editing system. All creative decisions and approvals are made during this process.

off-line editor – a low resolution, usually computer and disk based edit system in which the creative editing decisions can be made at lower cost and often with greater flexibility than in an expensive fully equipped online suite.   2. a person who performs the off-line work, completing preliminary editing done in a lower-cost editing facility, to prepare a list of edits for the final, or on-line editor. See also non-linear editor.

off the film metering – known also by its initials, OTF metering is an exposure meter reading that measures light reflected from the surface of the film during exposure.

ohm’s law  – defines the relationship between current, voltage, and resistance in an electrical circuit as proportional to applied voltage and inversely proportional to resistance. The formula is i=v/r. i = current (in amps), v = voltage (in volts), r = resistance (in ohms). When electric current in a material is proportional to the voltage across it, the material is said to be “Ohmic”, or to obey Ohm’s law. A microscopic view suggests that this proportionality comes from the fact that an applied electric field superimposes a small drift velocity on the free electrons in a metal. For ordinary currents, this drift velocity is on the order of millimeters per second in contrast to the speeds of the electrons themselves which are on the order of a million meters (~ 3,280,840 feet) per second. Even the electron speeds are themselves small compared to the speed of transmission of an electrical signal down a wire, which is on the order of the speed of light, 300 million meters (~ 984,251,968 feet) per second.

omnidirectional  – describes the shape of the area for microphones that have equal sensitivity to sound from nearly all directions.

omnidirectional microphone – a microphone pickup pattern which picks up sound equally well from all directions. See bidirectional, unidirectional.

omni-max –  a widescreen format, shot on 65 mm (2.56 inches) film and projected onto specialized large, dome-shaped screens. A trademark of imax corporation See IMAX.

omni mode –  a midi reception mode in which a module responds to incoming midi channel messages no matter what their channel.

on-air – the video signal in question is being broadcast or videotaped. In kaleidoscope, a portion of a channel’s picture is on screen or its output is being combined with another digital effects processor to create the final video output.

on-edge switching – a digital picture manipulator term meaning to switch input crosspoints (video sources) when the back (hidden) side of a double-sided transformed image rotates to the front and the front (visible) side rotates to the back. The switching occurs at the moment when only the edge of the image is visible.

on-line editing  – uses a more sophisticated and expensive editing system capable of transitions like dissolves and wipes. The process of final technical editing and preparation for distribution of film, with edits often from a list of changes created during off-line, which uses the original camera tapes to repeat all decisions made in the off-line editing process. Editing that is done to produce a finished program master.

on-line editor – 1. an editing system where the actual video master is created. An on-line bay usually consists of an editing computer, video switcher, audio mixer, 1 or more channels of DVE, character generator, and several video tape machines.  2. a person who performs the on-line work, who completes the final editing and preparation for distribution of film, with edits often from a list of changes created by the off-line editor.

one-to-one printing –  optical printing of the images which are reproduced to the same size.

opacity – 1. state or quality of being opaque. 2.  the degree to which a substance is or may be opaque.   3. the proportion of the light that is absorbed by the emulsion on any given area of the negative.

opaque – 1.  does not transmit light.  2. coloring used in photography to render parts of a negative opaque.

opaque bodies – objects that permit no light to pass through them, but reflect light.

Opaquer – an artist who colors in the individual cells of an animated film.

OpenFX –  open-source animation and modeling program.  Popular in the post production world because of flexible effects like lens flare, fog, explosions, waves and dissolving.

OpenGL – a graphics API that was originally developed by silicon graphics, inc. for use on professional graphics workstations.  OpenGL subsequently grew to be the standard API for CAD and scientific applications and today is popular for consumer applications such as PC games as well. OpenGL-ES is the version for embedded systems. A widely used 3d graphics language.

opening –  the time at which a movie is first released in theaters.  Movies will often open at different times in different countries or regions.

opening weekend – when a movie is first released in each country, its success is often measured in terms of its gross for the first weekend it opened. A disproportionate number of people usually see a movie on its opening weekend so box-office numbers are thought to be a good guide as to whether the movie will be a hit or not; however, they aren’t always that.

open up – increase aperture size to permit more light to reach the film or image sensor. If you change your lens’s aperture from ƒ/11 to ƒ/8, a larger opening, you have opened up by one stop. See also aperture, f-stop.

operator –  a term used in Yamaha’s FM synthesizers to refer to the software equivalent of an oscillator,envelope generator, and envelope-controlled amplifier.

optical discs –  characterized by a substrate laminated with either a stamped reflective layer or a separate recording layer and reflective layer. The discs are read by emitting a focused laser light on the recorded information and sensing the reflection.

optical effects –  trick shots prepared by the use of an optical printer in the laboratory, especially fades and dissolves.

optical fiber –  a glass strand designed to carry light in a fashion similar to the manner in which wires carry electrical signals. Optical fibers carry much more information than wires through multiple paths over long distances due to a characteristic called “pulse dispersion”.

optical glass – high-quality, color-free glass having specific refractive qualities, used in lenses and other components of optical systems.

optical printer  – 1. film printer used to blow up the image size of a neg. Also used for effects, zooms and mattes.  2. a laboratory machine for combining the images of one or more reels of film through photographic techniques.  3. an optical printer is used when image size of the print film is different from the image size of the pre-print film; also used when titles or effects (such as skip frames, blow-ups, zooms, and mattes) are included.  Contrast with digital compositing.

optical resolution – also referred to as “true resolution,” it means an image’s non-interpolated pixel dimensions.

optical soundtrack – a composite print in which the soundtrack is recorded via the varying width of a transparent track which runs beside the sequence of frames on a print. See also advance.

optical track – sound track in which the sound record takes the form of density variations in a photographic image.   Optical tracks are located on the edge of the print film.

optical viewfinder – 1. a camera viewfinder which has no electronics and therefore cannot reflect the actual picture being transmitted from the camera. Optical viewfinders for inexpensive television cameras are rangefinder viewfinders which are separate from the camera lens system and show a picture slightly different from that seen by the camera. The difference is most troublesome for subjects close to the camera where the angle of difference, or parallax, is greatest.   2.  A camera’s viewfinder (including those of DSLR cameras) that does not involve an LCD screen or an electronic aid to view a scene.  Think of a telescope or binoculars that are purely optical and have no electronic components. Some cameras  have optical and electronic viewfinders.

optical zoom – a true zoom effect unlike a digital camera’s digital zoom. Optical zoom changes the focal length of a lens.

opticals –  refers to film effects, film titles and film dissolves and fades.

optics – the branch of physical science that deals with the properties and phenomena of both visible and invisible light and with vision.

option – also optioning.  A contract to buy the exclusive rights to a script, within a specified time at a set price, effectively guaranteeing that during the indicated time period, the writer will not share the idea with anyone else.

orchestral arrangements – also arrangements, orchestrations, orchestration. An adaptation of the score for  instruments in an orchestra.

Orchestrator – a person who writes orchestral arrangements.

original –  an initial photographic image, or sound recording-whether photographic or magnetic- as opposed to some stage of duplication thereof.

original camera negative –  the negative originally exposed in a camera.

orthochromatic or “ortho” film –  1. representing correctly the relations of colors as found in a photographic subject.   2.  a photographic emulsion sensitive to all visible colors except red – i.e. an ortho film is sensitive to blue and green light.   3.  film that is sensitive to only blue and green light.

orthostereoscopic –  In 3D, a one-to-one condition where what is being displayed is the same as the ‘real world’. For example IMAX 3D is often shot with parallel cameras spaced at the average human adult interpupillary distance (approx 63.5 mm or 2.5 inches) and with wide angle lenses that closely match an audience members view of the screen.

Oscar – also –  Oscars, Academy Awards, Academy Of Motion Picture Arts And Sciences Awards. The term “Oscar” was coined by an anonymous person who remarked that the statue looked like their Uncle Oscar.

oscillator – an electronic device which generates a periodic alternating-current signal of a particular frequency, usually a sine wave, but sometimes a square wave or other waveform, at a frequency determined by the values of the components in its circuits. In an analog synthesizer, oscillators typically produce regularly repeating fluctuations in voltage – that is, they oscillate. In digital synthesis, an oscillator more typically plays back a complex waveform by reading the numbers in a wave-table.   2. Source of an electronic resonance.
3. An electronic sound source.

oscilloscope  – a test device that allows measurement of electronic signals by displaying the waveform on a CRT.

output – the current, voltage, power, or driving force delivered by a circuit or device.

output impedance – the impedance a device presents to its load.  The impedance measured at the output terminals of a transducer with the load disconnected and all impressed driving forces taken as zero. Its inverse is admittance, which is the reciprocal of impedance, the ease with which alternating current flows through a circuit.

output return loss – a measure of the accuracy of the impedance match between a signal source (such as a cable) and its terminating load. An unequal impedance match causes some of the power from the source to be reflected back to the source, resulting in signal distortion. The ratio of the signal voltage at the load to that voltage reflected back to the source is defined as the return loss. This ratio is generally expressed in decibels (dB).

output to output isolation – the ratio of attenuation provided by the output stage to an interfering signal driving one output compared to a second output. The ratio is measured at the second output. A good specification protects output signals against incorrect cabling, such as accidental connection or double termination.

out-takes – 1. sections of the negative that are not used for the final edit and are therefore removed from the final assembly. Footage not to be included in final production. 2. a take of a scene, which is not used for printing or final assembly in editing. In some movies, out-takes are shown under the closing credits.

output stage –  the last stage of the digital intermediate process. Typically the files in the digital intermediate are used to render a digital master. The digital master is recorded out to film and to create a variety of electronic formats.

over-cranking – the process of speeding the frame rate of a camera up, so that when the captured pictures are played at the normal frame rate the action appears to be in slow motion. Historically, cameras were operated by turning a crank at a constant, required speed; hence “over-cranking” refers to turning the crank too quickly. See also under-cranking, frames per second, judder.

overcoat – a thin layer of clear or dyed gelatin sometimes applied on top of the emulsion surface of a film to act as a filter layer or to protect the emulsion from abrasion during exposure, processing and projection.

overdub — to record supplementary tracks along with (or merged with) previously recorded ones. Overdubbing enables “one-man band” productions, as multiple synchronized performances are recorded sequentially.

over-expose – expose a photographic emulsion or a digital image sensor to more than light than is necessary for proper exposure.

overexposure –  a condition in which too much light reaches the film, producing a dense negative or a washed-out reversal.  Overexposure occurs when a sensor or film receives too much light causing the resulting photograph to be improperly exposed by too much light. It results in a loss of resolution (very fine detail), more graininess or digital noise and less detail in highlight areas. An overexposed negative is very dense resulting in light prints. An overexposed slide, or over-exposure with a digital camera, displays very light density. Intentional over-exposure or underexposure is known as increasing or decreasing exposure. An overexposed image is sometimes referred to as a “bleached out” photograph.

over-the-shoulder shot – view of primary camera subject framed by another subject’s shoulder and back of head in foreground. Common in interview situations, perspective affords sense of depth.  2. a camera shot over the first character’s shoulder capturing the second character opposite them; commonly used to show a conversation from the first character’s perspective.

overhead projector  – a device which produces an image on a screen by transmitting light through transparent acetate placed on the stage of the projector.

overlay –  keyed insertion of one image onto another.

overtone –  a whole-number multiple of the fundamental frequency of a tone. The overtones define the harmonic spectrum of a sound. See Fourier analysis, partial.

oxide – the magnetic coating on video and audio tapes that stores picture and sound information. Iron oxide is created by combining iron and oxygen. The more primitive form is called rust.

oxide tape – magnetic tape coated with fine particles of manganese oxide.

ozoner – slang for a drive-in theatre.  See also hardtop.