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Random Access Editing Systems
Nonlinear electronic video editing equipment that allows the editor to build an edited work tape out of sequence without having to rebuild or otherwise modify material on either side of a shot, sequence, or complete act. Random access editing systems are picture and sound switching systems. Rather than making electronic edits sequentially on piece of tape, they store the edit information in a computer’s memory and use it to switch from video playback sources to generate virtual edits.

Since no scenes are physically connected, they do not have to be reassembled to be modified. Instead picture switching based on computer data simulates edit frames accurately on a monitor and these edits will be repeated in the online session at a later date.

Resolution
A measure of the sharpness of an image. The ability of a system to reproduce fine detail and sharp edges. topˆ

Ringing
Seen on a monitor as a series of after-images following a sharp, high contrast horizontal transition; such as the trailing edge of a white object against a dark background. Excessive image enhancement used to increase the apparent resolution of a video image may cause this effect to appear. Video graphics devices (character generators, paint boxes) are relatively immune from this effect because of their controlled design. topˆ

Safe Title and Safe Action Areas
Geometric boundaries within the television viewing area used as a guide to insure the correct placement of graphics, titles of other types of art work so as not to lose the desired action or title information as seen on a television receiver. topˆ

Saturation
The intensity of the color in a video picture. Intensity may range from pale vivid or intense. The greater the color (chroma) saturation, the more intense the color. Excessive saturation leads to a form of transmission or recording distortion called "over deviation" or "bearding", or to color streaking sometimes know as bleeding color. The amount of color saturation may be seen on a vectorscope. topˆ

Scanner, Video
A precision round metal drum in a VTR or VCR driven by a servo motor on which two or more record/ play and erase heads are mounted along the circumference. topˆ

SCH (SubCarrier to Horizontal Phase)
Refers to the timing relationship that must exist between the color burst and the leading edge of sync to obtain clean color edits. The zero crossing of SCH must be time coincident with leading edge of horizontal sync. topˆ

Shedding
A condition of magnetic tape where the oxide that is bonded to the base has begun to separate from the base. When shedding is severe, the loose oxide is deposited on video and audio heads sometimes clogging them to a point of losing the image or sound completely. Stopping the machine and carefully cleaning the audio and/or video heads is the only way to correct this problem. topˆ

SMPTE Time Code
See Time Code. topˆ

Standards Converter
A device used to translate one television standard to another. For example, videotape made using the TNSC standard cannot be shown in a country that uses either PAL or SECAM unless the tape is first copied through a standards converter. Tapes may be copied from any one standard to any other standard through this device. topˆ

Standards, World Wide
Current world television standards are identified by country and format used. See World Television Standards. topˆ

Submaster
A high quality videotape made by copying or dubbing the edited master through VTRs equipped with time base correcting equipment. Any number of submasters may be made from a single master. A submaster is generally used as a backup or for making additional copies for broadcast, distribution, or viewing. topˆ

Sync, Electronic
The pulses in a video signal that provide a synchronizing reference for each frame and scanning line of the picture. Incorrect synchronizing pulses may cause the picture to roll vertically, jump erratically or tear out horizontally. topˆ

Sync, Editorial
The frame-to-frame relationship between the picture and sound during editing. Refers to no offset of the sound track to its corresponding picture frame. topˆ

Tape To Film Transfer Systems
Kinescope Recording (Also known as a "Kine")
The first of the video to film transfer systems. A photographic image of a television picture made by pointing a specially designed motion picture camera at a high-resolution television monitor. The image is photographed on 16mm or 35mm motion picture film and the resulting film after developing may be projected on a motion picture screen.

Several terms used interchangeably to define kinescope recordings are:

TVR: television recording
Tape to film transfers
Kine recording (now obsolete)
Although videotape has generally replace kinescope recordings for most applications, some film people still find special needs and applications for black and white kinescope recordings used as a work picture to aid sound technicians in creating sound effects or music cues. topˆ

Laser Scanning System
A second method of transferring videotape to motion picture film is illustrated in video to film laser recording. The videotape reproducer feeds the video into a "black box" that processes the signal. This decodes or separates the video into red, green, and blue components that modulate the light emanating from the three lasers. These light outputs are combined by mirrors into a single beam of light that is then mechanically scanned at the TV vertical and horizontal rate onto the film by a multi-faceted spinning mirror assembly. This light beam that has been adjusted for the television horizontal and vertical frame rate is focused onto the film plane of a special film camera that pulls the film down at a very fast rate during the vertical blanking period. Every fifth field is discarded electronically, which is how 30 television frames are converted to 24 film frames without severe motion artifacts. topˆ

EBR (Electron Beam Recorder)
A third type of transfer system - video to electron beam film recording - offers a high quality color videotape-to-film transfer using an electron scanning beam to sequentially expose a single film strip of consecutive black and white film negative images from red, green, and blue sources in a special vacuum chamber that encloses the film transport mechanism. Once developed, this black and white negative is used to generate a full color negative by sequentially printing on a frame-by-frame basis each group of three black and white film images through red, green, and blue filters directly onto color film. Video-to-film transfers made by this method are much higher quality than those made by the kinescope recording method. topˆ

Telecine
A motion picture film projector and a television camera or film scanner designed to transfer or convert motion pictures or slides and their associated sound elements to video and audio signals. topˆ

Telecine Formats
The most popular type of television projector/camera configuration is called a flying spot scanner. Most film is transferred in the 35mm format in the form of filmed television programs or feature films. topˆ

Wide screen film formats such as Cinemascope and Panavision may be transferred to videotape for use on television by using a sophisticated pan and scan method to select the most desirable areas of a scene. This preprogrammed information and selection of scene framing or panning is stored in a computer and may then be duplicated in real time as the film is recorded on videotape. Color balance and scene density information, as "painted" by the telecine operator, is also stored in the computer for later use. A relatively new form of telecine format is the three-perforation frame as opposed to the conventional four-perforation 35mm-picture frame. Since only three perforations are used in each film frame instead of four, an appreciable savings results by using 25% less of the film raw stock during production than would normally be used. The three-perf format affords similar savings for theatrical production and the entire frame area is used. The ideal format for TV would be three perf, 30 frame, which would result in slightly less film being used as in the present format. A 30-frame film format has greatly improved motion rendition, less grain pattern and an apparent increase in resolution. Most important for TV, which is the ultimate market for theatrical films, is the absence of 24 to 30 frame conversion artifacts, which are quite noticeable. However, the cost of theater conversion throughout the world, and the fact that the rest of the world’s TV systems demand 24/25 frame film make this an unlikely improvement. Both the camera used in production and the telecine used to transfer this special format have to be modified to accommodate this special format. topˆ

The second popular format is 16mm used in many industrial applications and some television programming film. Although not as widely used as in the past decade, 16mm, because of its comparatively low cost, fine grain, and good resolution, is still used to some degree by the military, industrial and documentary producers. A third format is Super 8mm. Although not as popular as 16mm and 35mm, it has a following among industrial and documentary producers who use this format to shoot on location in difficult areas where video may be too cumbersome to use. In many circumstances, it may important to avoid the appearance of professional equipment. topˆ

Another option is a device that reduces or eliminates the side to side picture weave of motion picture film. Conventional telecines exhibit some small amount of side to side picture weave because of the way the film is guided in the gate. Now, mechanical and electronic methods have been developed to almost completely eliminate this problem, which is very noticeable when electronic artwork or lettering is combined with moving motion picture images.Variable speed telecines also provide the film producer with limited special effects. For example, film shot at 16 frames per second, maintaining a real time look to the image. Other frame rates may also be programmed for special effects. topˆ

Television World Standards
There are more than 165 countries in the world that offer television to their citizens. Of these, 18% transmit black and white (monochrome), color transmissions in NTSC = 23%, PAL = 35%, and SECAM = 20%. The chart in Section 10 outlines in detail the various formats and other specifications used around the world. topˆ

Time Base Error
The horizontal and/or vertical jitter inherent in most videotape recording equipment. Broadcast standards require a horizontal line-to-line timing accuracy of better than one part in thousands, which is impossible to attain in a mechanical tape-scanning device. An electronic automatic time delay device, known as a Time Base Corrector (TBC) is necessary in all helical scan VTRs to compensate for this inherent problem if the video is to be broadcast or composited (dissolve, wipe, matte) in any way. Consumer and industrial machines cannot afford this feature and rely on fast horizontal automatic frequency control (AFC) circuits in monitor and receivers to cover this fault. topˆ

TBC (Time Base Corrector)
An electronic processing device connected to the output of a VCR or VTR that removes or masks the jitter generated by unavoidable mechanical inaccuracies in helical scan recorders. This is accomplished by automatically delaying the video signal so that each line starts at the proper time. The TBC can be an integral part of the recorder (professional) or may be an external stand-alone device (industrial/consumer). It may also include a video-processing amplifier that allows the adjustment of video and color levels in the corrected signal. topˆ

Time Code (TC)
A standardized numbering system referenced to a 24 hour clock by which audio or video material is specifically identified for editing or reference purposes. The system assigns a unique, eight-digit number to every frame on an audio or videotape. This number assumes the following form:

Up to 23 hours
Up to 59 minutes
Up to 59 seconds
Up to 29 frames

The maximum time that could be displayed would be 23:59:59:29. After that, the display would start over again at zero. A typical time code would be displayed as 14:23:06:17. topˆ

Time Code Generator (TCG)
An electronic clock that generates a digital serial code that can be recorded on an audio track, which assigns to each video or audio frame a unique identification number composed of eight digits. topˆ

Tracking
The process by which the video head precisely follow the recorded video signal on playback. Correct tracking assures a noise free reproduction of the picture. Mistracking of the video head with respect to the recorded signal on the tape results in video distortion seen as noise; or in the worst case, breakup of the image since the video head is not riding directly over the recorded signal on the tape. The control track provides the reference for tracking. The tracking control allows a "fine tuning" adjustment for non-standard tapes. topˆ

 

 

 

 


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