- 4x3Aspect ratio of 4 units wide by 3 units high is the current standard for TVs in the United States. Can also be described as 1.33 aspect ratio. Also referred to as 4/3 and 4:3.
- 16x9Aspect ratio of 16 units wide by 9 units high is a wider format than the current 4x3 TV standard. This is the standard aspect ratio for widescreen TVs and HDTV. Can also be described as a 1.78 aspect ratio, i.e. width is 1.78 times height. Also referred to as 16/9 and 16:9.
- A/DAnalog to digital conversion.
- Addressable ResolutionThe inherent resolution of a display device (plasma screen, television, projector or monitor) which enables pixels to be individually addressed. The device, however, may not be capable of displaying this resolution.
- AliasingAn artifact produced by distorting or not using the high frequency components of an image, signal, data stream, etc. due to some limitation such as undersampling or inadequate detection bandwidth. The result is unwanted appearance of low frequency components (aliases) which must be filtered out and replaced with the missing high frequency components. The process of removal/replacement of frequencies is called "anti-aliasing".
- AnalogA form of data transmission using a continuously variable signal, in contrast to digital transmission, which uses discrete numerical steps.
- Analog TV"Standard" television broadcasts analog TV. Analog signals vary continuously, representing fluctuations in color and brightness. NTSC is an analog system.
- AnamorphicA process of storing images with different horizontal and vertical magnifications for later display through a reversed procedure. Generally, the image is squeezed inward from the sides in relation to the height. So, if the original picture is of a circle, then the anamorphic processing would produce a tall, thin oval. On receiving the signal, some device will readjust these different horizontal and vertical magnifications back to normal. The anamorphic process has the advantage of enabling wide aspect ratio pictures to be stored on a recording medium originally designed for the 4x3 aspect ratio. Specifically, an anamorphic DVD stores a high quality widescreen movie for viewing on widescreen TVs.
- ANSI LumensA unit that indicates lumen brightness of projectors. ANSI (American National Standards Institute) has established the standard for measurement of lumen brightness. For example, if one projector uses Halogen lamps and another metal-halide, the halogen projector will seem noticeably dimmer even if the two units rate the same.
- Anti-aliasingIn electronic communication, the term refers to the adding of additional images or parts of images so as to convince the eye that it sees something that cannot be represented digitally. The goal is usually to make curved or diagonal lines appear smooth, or to show straight horizontal or vertical lines in certain positions. Lines cannot be represented smoothly or in the proper position because the display device resolution is not sufficient to represent the image accurately. In practice, the eye is fooled into completing the edge between the background and foreground colors.
- ArtifactsUnwanted visible effects in a picture created by disturbances in the transmission or image processing, for example "edge crawl" or "hanging dots" in analog pictures, or "pixelation" in digital images.
- Aspect RatioThe aspect ratio of a display screen is described by the width x height, for example 4x3 means 4 units wide by 3 units high. Current U.S. TV broadcasts use a 4:3(1.33:1) aspect ratio. Digital TV is broadcast with a 16:9 (1.78:1) ratio, and most feature films are shot in the ratio range of 1.85:1 up to 2.35:1.
- ATSCThe Advanced Television Systems Committee Inc., is an international, non-profit organization developing voluntary standards for digital television. The ATSC member organizations represent the broadcast, broadcast equipment, motion picture, consumer electronics, computer, cable, satellite, and semiconductor industries. The most common formats are 480p (525 scan lines, 480 of them active, per frame progressive scan, each scan line divided into 640 or 704 parts or pixels, 720p which is 720 active scan lines each with 1280 pixels, and 1080i (1080 active scan lines as two 540 scan line interlaced fields, 1920 pixels on a line).
- ATTCThe Advanced Television Technology Center is a private, non-profit corporation organized by members of the television broadcasting and consumer products industries to test and recommend solutions for delivery and reception of a new U.S. terrestrial transmission system for digital television (DTV) service, including high definition television (HDTV). The Technology Center operates a state-of-the-art laboratory facility that supports the needs of the U.S. television industry and private standards-setting bodies. Its primary activity is to facilitate implementation of digital television. Website: www.attc.org
- BandwidthA range of frequencies used for transmitting information such as images and sound. For U.S. television broadcasters, the Federal Communications Commission (FCC) has allocated 6MHz for each channel. For DTV, the maximum bit rate possible within the bandwidth is 19.4 Mbps, which is used by one HDTV channel. SDTV has a lower bit rate, therefore the same bandwidth can accommodate more than one channel.
- Blu-rayBlu-Ray, also known as Blu-ray Disc (BD) is one of the next generation optical disc formats, developed by the Blu-ray Disc Association (BDA), a group of leading consumer electronics and PC companies (including Apple, Dell, Hitachi, HP, JVC, LG, Mitsubishi, Panasonic, Pioneer, Philips, Samsung, Sharp, Sony, TDK and Thomson).The new format is designed to replace the existing DVD technology, and allows recording, rewriting and playback of high-definition video (HD), as well as storing large amounts of data. A single layer Blu-ray Disc can hold 25GB, which can be used to record over 2 hours of HDTV, or more than 13 hours of standard definition TV. Dual layer versions can hold 50GB, and versions with more layers are planned. While the current DVD technologies use red laser to read and write data, the new format uses blue-violet laser, hence the name, Blu-ray. In spite of the different types of laser used, the new Blu-ray products can easily be made backwards compatible, allowing playback of existing CDs and DVDs. The advantage of the blue laser is that the shorter wavelength allows for more precise focus, and therefore it becomes possible to pack data more tightly on the same size disc. The following formats are part of the Blu-ray Disc specification: BD-ROM - read-only format for software, games and movie distribution. BD-R - recordable format for HDTV recording and PC data storage. BD-RE - rewritable format for HDTV recording and PC data storage. Blu-ray is one of the emerging technologies expected to replace VCRs and DVD recorders over the coming years, with the transition to HDTV. One of these formats will become the new standard for PC data storage and HD movies in the future. See also HD-DVD.
- BNC ConnectorA connector that has a bayonet-type shell with two small knobs on the female connector which lock into spiral slots in the male connector when it is twisted on. This connection is preferred by professionals because of its perfect 75ohm impedance and positive locking connection. Different sources expand BNC as Bayonet Navy Connector, British Naval Connector, Bayonet Neill Concelman, or Bayonet Nut Connection.
- CEAThe Consumer Electronics Association (CEA) membership unites more than 1700 companies within the U.S. consumer technology industry. Member-only resources include: exclusive information and unparalleled market research, networking opportunities with business advocates and leaders, up-to-date educational programs and technical training, exposure in extensive promotional programs, and representation from the voice of the industry, CEA, promoting and advancing member needs and interests.
- CEDIAThe Custom Electronic Design & Installation Association (CEDIA), is a global trade association of companies that specialize in planning and installing electronic systems for the home. These systems include home networking, home automation and communication systems, media rooms, single or multi-room entertainment systems, and integrated whole-house subsystems providing control of lighting, security and HVAC systems. The association was founded in September 1989 and has a total membership of more than 3,000 member companies. The Cedia Expo Show is held annually in September.
- CESThe Consumer Electronics Show is an annual convention held in Las Vegas each January that promotes the industry and its products.
- ChromaThe color information contained in a video signal.
- Chroma DelaySlight horizontal shifting of color relative to the luminance details of the picture giving the appearance of a poorly done child's coloring book. It can result from less than perfect circuitry or cables where the color subsignals take a longer or shorter time to arrive at the display screen.
- Chroma Upsampling ErrorAlso referred to as the chroma bug, this error occurs because most digital video has every two scan lines sharing the same coloration. The bug manifests itself as thin black horizontal strips occurring every other line, or alternating between two colors near edges of sharply contrasted color objects. A good place to spot this artifact is in the Toy Story main menu (the blue text).
- Coaxial CableA standard cable used for many video connections, consisting of a central inner conductor, wrapped in a cylindrical outer conductor.
- Comb FilterAn electronic filter that is used to separate luminance and color information from an input composite video signal. (Color and luminance must subsequently be recombined in a different way, namely isolate red, green, and blue content,ÿto produce the picture.) Comb filters are used in the medium grade to more expensive TV sets to perform the necessary task of separating the two.ÿNotch and bandpass filters, common on lower priced TV sets as an alternative, produce acceptable pictures but with more discoloration and limited horizontal resolution.
- Component VideoThe output of a video device (such as a DTV set-top box or DVD player), may be transmitted in component video format, or the input of a DTV receiver or monitor consisting of the 3 component signals: luminance or brightness (Y) and two color difference signals (PB, PR), each on a separate wire.
- Composite VideoAn analog, encoded video signal (such as NTSC) that includes vertical and horizontal synchronizing information. Since both luminance (brightness) and chrominance (color) signals are encoded together, only a single connection wire is needed. A composite signal is typically carried on a single cable with a yellow red connection at each end.
- CompressionA method of electronically reducing the number of bits required to store or transmit data within a specified time or space. The video industry uses several types of compression methods but the method adopted for DTV and DVD is called MPEG2.
- Computer MonitorsIn general, almost all computer monitors will work with the iScan. The only requirement is that the monitor be capable of being used at a VGA resolution (640x480) at 60Hz (frames per second). Since this is currently the lowest common denominator for computer monitors, only very old monitors may not be compatible. The biggest drawback to using a computer monitor as a television is that they are typically not as bright as televisions. In addition, with computer monitors, you won't have access to all of the fancy Picture-in-Picture, stereo audio and other features typically found in today's TVs.
- CRTA Cathode Ray Tube is one of the main components of monitors and TVs. A beam of electrons is shot towards the CRT and as they collide with phosphors on the inside surface, they produce light. Newer technologies are now available, such as LCD panels and projection units which are not so heavy or bulky as the old CRT monitors and TVs. As CRTs are phosphor based, they are susceptible to differential aging of the phosphors, commonly referred to as image retention or burn-in.
- D/ADigital to analog conversion.
- DBS (Digital Broadcast Satellite)Digital format for music and video that beams high-powered signals across North America from satellites orbiting above the equator to satellite dishes providing a wide range of programming in a high-quality digital format. Direct broadcast satellites are positioned above the equator in geostationary orbit, meaning that the satellite orbits at the same speed as the spin of the earth, so is always facing the same part of the globe. The satellites beam down a high-powered signal in a broad spectrum of radio frequencies. The small 18 inch satellite dishes receive the signal and transfer it to a decoder box in the home. The decoder box then decodes the digital data and supplies an analog video and audio signal to the video display and audio system. The digital video and audio feed from a direct broadcast satellite is encoded with MPEG-2 compression.
- DeinterlacingDeinterlacing is the complex process that converts a traditional interlaced video source into the progressive scan format required by modern high definition displays. However, not all deinterlacing processors are equal, and some of the other interlacers on the market will leave you looking at noisy artifacts and motion blurs. Not ours! DVDO technology delivers state-of-the-art progressive-scan video for the best possible picture from interlaced video sources enabling flawless, seamless, source-adaptive and motion-adaptive deinterlacing.
- DigitalExpressed or represented by a series of numbers. For example, a digital signal is expressed by the numerical value of the signal size at regular points in time. Sounds and pictures can be recorded, stored, and played back digitally with no distinguishable difference from the original if the time interval between samples is sufficiently small.
- Digital ImageA video image converted into pixels. The numeric value of each pixel can be stored in a computer memory for subsequent processing and analysis.
- Digital TVIn the U.S., this term is commonly used to refer to a TV set that can display HDTV broadcasts. Actually many HDTV sets use analog processing for HDTV, they have no HDTV tuner built in and the HDTV video signal fed from an external tuner has been fully decoded and converted to analog. On the other hand, the best display of analog broadcasts requires digital components, namely the comb filter and a de-interlacer and/or scaler.
- Direct View TelevisionDirect View is the formal name for a normal "tube" TV. They are based on large CRTs (cathode ray tubes) that project the image onto a the surface of a phosphor-lined glass screen which you view directly, hence the name. Some other devices, such as projectors may also use CRTs but they project the image onto a separate screen. Direct View sets, if they are capable of accepting a 31.5kHz progressive signal, are typically much improved with a DVDO iScan. Some of these sets may have their own internal line doubler or "upconverter" which is used to convert the incoming 15.75kHz (normal) signal to 31.5kHz (or higher). The advantage of the DVDO iScan in these cases is that it does a much better job of this upconversion than any of the current generation of embedded line doublers.
- DLPAt the heart of every Digital Light Processing projection system is an optical semiconductor known as the Digital Micromirror Device, or DMD chip, which was invented by Dr. Larry Hornbeck of Texas Instruments in 1987. The DMD chip is probably the world's most sophisticated light switch. It contains a rectangular array of up to 2 million hinge-mounted microscopic mirrors; each of these micromirrors measures less than one-fifth the width of a human hair. When a DMD chip is coordinated with a digital video or graphic signal, a light source, and a projection lens, its mirrors can reflect an all-digital image onto a screen or other surface. The DMD and the sophisticated electronics that surround it are what we call Digital Light Processing technology.
- Dot PitchThe (center to center) spacing between phosphor dots or stripes of the same color on a display screen. The smaller the better for picture sharpness, 0.28 mm is considered the minimum acceptable for a good computer display, while a typical 20" TV has an 0.81 mm dot pitch and large screen TV's have larger dot pitches. Many TV screens use vertical stripes rather than dots in which case the dot pitch applies only in the horizontal direction.
- DownconvertA term used to describe the format conversion from a higher resolution input signal number to a lower display number, such as 1080i input to 480i display.
- DTVRefers to standard or high definition TV whose signals are digital during production, transmission, storage, and reception. DTV has many advantages. It can be compressed to provide four, five or more channels in the same bandwidth required for one channel of NTSC television (the current U.S. standard). Digital television provides a crystal clear, "snow-free" picture to all TVs that can receive a minimum level signal. Within the DTV or ATSC (Advanced Television Systems Committee) standard, there are 18 current formats, several of which are called HDTV. Broadcasters will have the option of showing several SDTV programs or one or two HDTV programs, all with a single DTV channel. Note: Even digital TV signals are converted to analog to pass through component video or S-video cables and/or just before being displayed on a picture tube. The fewer analog/digital conversions there are altogether, the better the overall quality can be.
- DVDThe Digital Video Disc or Digital Versatile Disc, is similar to a CD-ROM except that it stores up to 12 times as much data. DVD is the successor to CD-ROM technology. DVD discs are the same size physically as CD-ROM discs, but hold between 4.7 - 18 GB of data. Initial DVD drives were read-only devices, but newer versions work with rewriteable media.
- DVIDigital Visual Interface (DVI) is a type of cable and connection created in 1999 by the Digital Display Working Group (DDWG), which is a cooperative of technology companies including Silicon Image, Intel, Compaq, Fujitsu, HP, IBM and NEC. The DVI 1.0 standard was originally created to enable digital-to-digital, high bandwidth data transfer between a computer and a flat screen monitor. However, because of DVIs ability to also process high-bandwidth HDTV video, interest was generated in the consumer electronics industry. DVI is the fastest way to transfer data or video. Using DVI with a digital display device, such as a projector or flat screen monitor, will create an entirely digital-to-digital connection, providing the consumer with the best quality image.
- DVI 1.0 specificationDVI-D: Digital Only DVI-I: Digital and Analog DVI-A: Analog Only Dual Link: Dual Link DVI supports 2x165 MHz (2048x1536 at 60 Hz, 1920x1080 at 85 Hz). A dual link implementation utilizes all 24 of the available pins. Single Link: Single Link DVI supports a maximum bandwidth of 165 MHz (1920x1080 at 60 Hz, 1280x1024 at 85Hz). A single link implementation utilizes 12 of the 24 available pins.
- EBUThe European Broadcasting Union (EBU) is the largest professional association of national broadcasters in the world. The Union has 72 active Members in 52 countries of Europe, North Africa and the Middle East, and 50 associate Members in 30 countries further afield. The EBU was founded in February 1950 by western European radio and television broadcasters. It merged with the OIRT - its counterpart in Eastern Europe - in 1993. The Union is in the forefront of research and development of new broadcast media, and has led or contributed to the development of many new radio and TV systems: radio data system (RDS), digital audio broadcasting (DAB), digital television (DVB), high- definition TV (HDTV). At its office in Brussels, the EBU represents the interests of public service broadcasters before the European institutions.
- EDEnhanced definition is a signal that is either 480p (NTSC) or 576p (PAL) that can be either 4:3 or 16:9. Fox has broadcast shows like 24 in EDTV with a 16:9 ratio.
- EDIDExtended Display Identification Data is a VESA standard data format that contains basic information about a monitor and its capabilities, including vendor information, maximum image size, color characteristics, factory pre-set timings, frequency range limits, and character strings for the monitor name and serial number. The information is stored in the display and is used to communicate with the system through a Display Data Channel (DDC), which sites between the monitor and the PC graphics adapter. The system uses this information for configuration purposes, so the monitor and system can work together.
- FCCThe Federal Communications Commission (FCC) is an independent United States government agency, directly responsible to Congress. The FCC was established by the Communications Act of 1934 and is charged with regulating interstate and international communications by radio, television, wire, satellite and cable. The FCC's jurisdiction covers the 50 states, the District of Columbia, and U.S. possessions.
- FieldHalf of an interlaced video frame containing either all the odd or all the even numbered horizontal lines. The frame is the entire image consisting of two fields. An interlaced image such as the NTSC analog television standard draws all the odd lines of an image followed by all the even lines of an image (first drawing lines 1, 3, 5, 7, and so on then coming back to draw lines 2, 4, 6, 8, and so on). A field consists of all the odd or even lines that combine to create a complete image.
- FirewireA type of cabling technology for transferring data to and from digital devices at high speed. Some professional digital cameras and memory card readers connect to the computer over FireWire. FireWire card readers are typically faster than those that connect via USB. Also known as IEEE 1394.
- Fixed Pixel Display (FPD)An all encompassing term for technologies that have pixels rather than scan lines like a CRT. LCD, DLP, plasma and LCoS are popular technologies that are used in fixed pixel displays.
- Flat Panel Display (also known as FPD)A type of display that is much thinner compared with standard CRT based displays. Plasma and LCD screens are both types of FPDs.
- Flat ScreenA type of picture tube, based on CRT technology, which has front glass which is flat rather than the typical curved surfaced. Not to be confused with flat panel displays.
- FrameOne complete screen in a video image. A single frame is related to a single picture or a single photograph. By combining multiple frames in rapid succession, the illusion of motion is created. In the movies, 24 frames pass by every second. On television, there are 30 frames displayed each second.
- Frames Per Second (FPS)A measure of the number of pictures (or frames) that are displayed per second to create a moving image. For TV, this is typically between 50 and 60 FPS.
- Game ModeAnchor Bay's Precision Deinterlacing Card offers a Game Mode - What does that mean? The complex algorithms involved in video processing take time to run. If you're watching a DVD, TV program or a movie, the slight delay between input and output is not apparent, and the quality of the displayed images is of prime importance. However, for gaming applications, the ability to minimize that processing delay is crucial. Many competitive video processors produce upwards of a 7 frame delay as they apply the algorithms. This can mean an unacceptable delay for serious gamers who want a real-time response to their commands in order to get peak performance from their applications. Game Mode 1: slightly less than one frame delay, while still performing edge adaptive deinterlacing. Game Mode 2: will reduce frame delay down to 2 frame delay with edge and motion adaptive processing The Precision Deinterlacing Card is an optional extension module for the DVDO iScan VP30 or iScan VP20.
- Gas Plasma DisplayA type of monitor technology typically used to create large monitors that are only a few inches thick. The technology works by creating a matrix of red, green and blue pixels from plasma bubbles that are turned on or off by selectively powering them.
- HD-DVDHD-DVD, also known as Advanced Optical Disc (AOD) is one of the next generation optical disc formats, developed by Toshiba and NEC. The new format is designed to replace the existing DVD technology, and allows recording, rewriting and playback of high-definition video (HD), as well as storing large amounts of data. The new high-definition movies, which have a much clearer image, require up to 5 times as much storage space. A single layer HD-DVD can hold 20GB which is just over 1 hour of high-definition video, or 6 hours of standard definition video. A dual layer version can hold 30GB. While the current DVD technologies use red laser to read and write data, the new format uses blue-violet laser. The advantage of the blue laser is that the shorter wavelength allows for more precise focus, and therefore it becomes possible to pack data more tightly on the same size disc. There are three versions in development: HD DVD-ROM discs are pre-recorded and offer 15 GB per layer per side, offering up to 30 GB per side or 60 GB per disc. These can be used for distributing HD movies. HD DVD-RW discs are re-writable and can be used to record 20 GB per side for re-writable versions. HD DVD-R discs are write-once recordable discs with a capacity of 15 GB per side. HD-DVD is one of the emerging technologies expected to replace VCRs and DVD recorders over the coming years, with the transition to HDTV. One of these formats will become the new standard for PC data storage and HD movies in the future. See also Blu-ray
- HDCP (High-Bandwidth Digital Content Protection)A standard, developed by Intel, that protects digital video and audio signals transmitted over DVI or HDMI connections between two HDCP-enabled devices. The nature of a digital signal makes it possible to create perfect copies of the original signal an unlimited number of times without degradation, something that is impossible with an analog signal. So, in order to protect copyright holders (movie studios, etc.) from having their programs copied and shared, the HDCP standard provides for the secure, encrypted transmission of digital signals. HDCP only functions across DVI or HDMI connections between two HDCP capable devices. The source device (such as a DVD player or HDTV tuner) encrypts the digital signal using the HDCP standard, then sends that signal over the DVI or HDMI connection to the receiving device (HDTV, etc.). The receiving device decodes the signal using HDCP and uses the signal as it is allowed. If one of your devices is HDCP compliant, but the other is not, then you cannot connect them using DVI or HDMI - you will get an error. However, you can still use the analog signal from the source device (eg: component video signal, S-video signal). HDCP does not apply to analog signals. The FCC approved HDCP as a "Digital Output Protection Technology" on August 4th, 2004. FCC regulations will require digital output protection technologies on all digital outputs from HDTV signal demodulators as of July 1st, 2005.
- HDMIHigh Definition Multimedia Interface is the first industry-supported, uncompressed, all-digital audio/video interface. Based on the earlier DVI (video only) standard, HDMI provides an interface between any audio/video source, such as a set-top box, DVD player, and A/V receiver and an audio and/or video monitor, such as a digital television (DTV). HDMI supports standard, enhanced, or high-definition video, plus multi-channel digital audio on a single cable. It transmits all ATSC HDTV standards and supports 8-channel digital audio, with bandwidth to spare to accommodate future enhancements. HDMI will offer 'legacy' support of older DVI connections.
- HDTVThe new High-definition television standard displays and broadcasts signals that use many more scan lines than normal television and a 16x9 aspect ratio rather than the old 4x3 aspect ratio of a standard TV set. HDTV also refers to the televisions that pick up these signals. Japan first used an analog form of HDTV. The United States, and now Japan use a digital form of HDTV, or DTV. HDTV does not degrade through many generations of editing, which means he final broadcast is crystal clear. The resulting picture is up to five times sharper than that of today's sets, with CD-quality sound. HDTV offers reduced artifacts (i.e. ghosting, dot crawl), and provides 5.1 independent channels of CD-quality stereo surround sound, (also referred to as dolby digital). An analog TV signal in the U.S. has 525 scan lines for the image, and each image is refreshed every 30th of a second (half of the scan lines are painted every 60th of a second in what is called an interlaced display). 480 of 525 scan lines are used to hold the picture. We can also call it 480i. The formats used in HDTV are as follows: 480i - 640 x 480 pixels interlaced; 480p - 640 x 480 pixels progressive; 720p - 1280 x 720 pixels progressive; 1080p - 1920 x 1080 pixels progressive
- Horizontal ResolutionA measure of the quality of a displayed image, relating to the number of vertical lines, or individual picture elements across the screen from left to right. The greater the number of vertical lines (or picture elements across the screen), the greater the resolution. Higher resolutions result in images which are better defined and complete. There are two primary HDTV standards, 1080i and 720p. With 1080i the resolution is set at 1920 pixels across (horizontal resolution) and 1080 pixels top to bottom (vertical resolution). The 720p standard provides for 1280 pixels across (horizontal resolution) and 720 top to bottom (vertical resolution).
- Horizontal Scan RateThe number of horizontal lines of information a video display can paint on to a screen in one second, given in hertz (Hz - cycles per second). The horizontal scan rate of analog NTSC video is 15,750 Hz, which, at a refresh rate of 60 screens per second gives 262.5 as the maximum number of lines that can be displayed (vertical resolution). In a similar way, a graphics projector with a horizontal scan rate of 63,000 Hz has a vertical resolution of 1,050, and a data grade projector (31,500 Hz horizontal scan rate) can furnish 525 horizontal lines.
- IEEE 1394The Institute of Electrical and Electronics Engineers specification 1394 (IEEE 1394 also called FireWire and iLink) is the transmission standard and connector found on many consumer electronics products, including camcorders, DTVs, set-top boxes, A/V receivers, and some DVD players. Most signals sent over IEEE 1394 are compressed, which means they can be recorded.
- Interlaced ScanFor television display, interlaced scanning refers to the process of transmitting and re-assembling a single picture frame from two passes of the image. First the odd lines (1,3,5,...) are transmitted together, and displayed on screen. Next, the even lines (2,4,6,...) for the same frame are transmitted and displayed. The entire frame is displayed in two passes, or scans, each taking 1/60th of a second. The human eye sees it as a single picture, however, because of the persistence of the CRT phosphor. Interlaced video was originally invented to reduce flicker given that video technology of the time could not draw video frames fast enough to keep the top of the picture from fading before the bottom of the picture was completed. See also Progressive Scan.
- JitterSmall, rapid varitaions in waveform or image due most often to mechanical disturbances.
- JPEG (Joint Photographic Experts Group)JPEG is a digital compression standard for still video images that allows the image to occupy less memory or disk space.
- LCD PanelA Liquid Crystal Display Panel uses liquid crystal sandwiched between two layers of specially treated glass. When an electrical current is sent through the treated glass, it changes the phase of the liquid, resulting in a color change.
- LCoSLCos could be considered a hybrid between LCD and DLP. LCD uses liquid crystals, one for each pixel, on glass panels. Light passes through these LCD panels on the way to the lens and is modulated by the liquid crystals as it passes. Thus it is a "transmissive" technology. On the other hand, DLP uses tiny mirrors, one for each pixel, to reflect light. DLP modulates the image by tilting the mirrors either into or away from the lens path. It is therefore a "reflective" technology. LCOS combines these two ideas. It is a reflective technology that uses liquid crystals instead of individual mirrors. In LCOS, liquid crystals are applied to a reflective mirror substrate. As the liquid crystals open and close, the light is either reflected from the mirror below, or blocked. This modulates the light and creates the image. LCOS-based projectors typically use three LCOS chips, one each to modulate light in the red, green, and blue channels. In this it is similar to an LCD projector which uses three LCD panels. Both LCOS and LCD projectors deliver the red, green, and blue components of the light to the screen simultaneously. There is no spinning color wheel used in these projectors as there is in single-chip DLP projectors.
- LetterboxOne of the formats used to display pictures recorded at a wider aspect ratio than the display device permits. In letterbox format, the full image is displayed at the original aspect ratio, with the rest of the screen filled in with black (at the top and bottom).
- Line DoublerDigital video processor that enhances the picture quality of a video image by combining the two interlaced fields (all the odd lines followed by all the even lines) to produce a single progressive scan frame of the image. Each doubled field is then a complete frame that is projected 60 times per second. Line Doublers must also contain complex processing circuitry to compensate for the shortcomings of the incoming interlaced video, and the mismatches that could be created by combining the two fields. The result is an image with much greater detail and clarity than the original interlaced video source.
- Line DoublingA method of converting an interlaced picture into a progressively scanned picture. Special circuits combine the odd and even lines, then scan all 525 lines in 1/30th of a second. The result is improved detail enhancement from an interlaced source. High quality de-interlacers use techiques more complicated than just delivering each scan line twice.
- Lip Sync. ErrorA situation in motion pictures when the picture and sound do not match in time. The sound or the picture has been delayed, so, for example, the lips do not move in time to the speech.
- LumensA standard for measuring light output, used for comparing projectors. However, the rating does not always match the perceived brightness. For example, if one projector uses Halogen lamps and another metal-halide, the halogen projector will seem noticeably dimmer even if the two units rate the same.
- MacrovisionMacrovision, Inc has developed an anti-taping process for video systems that output analog NTSC, PAL, RGB or YUV video. The video source may be from DVD, VCR, or set top box. Whether or not the anti-taping process is present on the video outputs is determined by the source. Macrovision works due to the differences in the way VCRs and televisions operate. The automatic gain control (AGC) circuits within a television are designed to respond slowly to change; those for a VCR are designed to respond quickly to change. The Macrovision technique attempts to take advantage of this by modifying the video signal so that a television will still display it properly, yet a VCR will not record a viewable picture. DVD players typically have Macrovision circuits built in to make copying of DVD movies impossible.
- MoireA distracting wavy effect produced when converging lines in a video image are nearly parallel to a monitor's scanning lines.
- Motion AdaptiveA processing strategy of de-interlacing line doublers and comb filters whose optimizing formula varies, depending on whether the subject matter depicted was stationary/steady or moving/changing. The best devices may vary their processing dozens of times within a single scan line.ÿThe device must digitize several video fields, save them on a rolling basis, and compare the content in small groups of pixels to determine whether subject matter was moving or not.
- MPEG2High-quality audio/video compression format developed by the Motion Picture Experts Group using perceptual coding and predictive technologies similar to MPEG-1 but including a higher bit-rate and more control over the compression and technology. MPEG-2 features a bit-rate of 3.5 to 10 megabits per second as opposed to MPEG-1s 1.5 megabits per second. The MPEG-2 format can be used to provide very high-quality images and is used with DVD, DBS (direct broadcast satellite) and HDTV (in a modified high-resolution format).
- MPEG4MPEG-4 was defined by the Moving Picture Experts Group (MPEG) and is designed to deliver DVD (MPEG-2) quality video at lower data rates and smaller file sizes. Like MPEG-1 and MPEG-2 previously did for CD-ROMs and DVDs, MPEG-4 promises to create interoperability for video delivered over the Internet and other distribution channels. MPEG-4 will play back on many different devices, from satellite television to wireless devices.
- NABThe National Association of Broadcasters represents the radio and television industries in Washington -- before Congress, the FCC and federal agencies, the courts, and on the expanding international front. NAB provides leadership and resources to their supporting members, to broadcasters at-large, and through ongoing public campaigns to the American people.
- Native ResolutionAll fixed-pixel TVs, including every flat-panel LCD and plasma, as well as rear-projection DLP and LCD TVs, have a certain number of pixels, known as the native resolution, that they use to create the picture. Most widescreen DLPs have a native resolution of 1280 x720 as an example.
- NTSCNational Television Standards Committee The organization responsible for setting the standard for broadcast and reception of television signals in the United States. The original NTSC standards were defined in 1953, and set 525 horizontal lines of resolution, interlaced scanning and a 60Hz refresh rate. It combines blue, red, and green signals with an FM frequency for audio. The new HDTV standard will replace NTSC over the next few years.
- Optical (TOSLINK)TOSLINK is a standardized optical fiber connection system for consumer audio equipment, which carries digital audio streams between components such as DVD players and satellite receivers.
- OSDOn Screen Display is a menu displayed on the screen with different options to help users easily adjust the display's picture.
- OverscanOverscan results in only part of the viewable image being shown on the TV or display. It's deliberately done by TV manufacturers to avoid any messy artifacts at the edges due to picture quality or an inferior power supply. But the result is that you may be missing a significant part (up to 15%) of the real picture.
- PALThe television standard for signal processing and broadcasting used throughout the majority of Western Europe (except France where SECAM is the standard), South America, Asia, and Oceania. The PAL standard broadcasts 625 lines of resolution, nearly 20 percent more than the U.S. NTSC standard that uses 525 lines, but at only 50 fields/second versus NTSC's 60. PAL, SECAM and NTSC are not interchangeable with each other.
- Pb, PrRefers to the color component video signals B-Y and R-Y respectively with optimization for analog component video purposes or transmission.
- PixelA single dot or group of three dots (red, green and blue) on a display. Total display pixels are usually expressed in horizontal x vertical dimension (e.g., 800x600).
- Plasma Display Panel (PDP)Plasma Display Panel technology is based on the same principle as the fluorescent light, using thousands of sealed, low pressure glass chambers filled with a mixture of noble gasses. Behind these chambers are colored phosphors, one each of red, blue, and green for each chamber. When energized, the chambers of plasma emit invisible UV light, which then strikes the red, green and blue phosphors on the back glass of the display making them produce visible light.
- Progressive ScanMost computer monitors, and some high-definition TV sets use progressive scan, as opposed to the NTSC standard of interlaced. In progressive scanning, all the horizontal scan lines for a single frame are painted on the screen from top to bottom in a single pass. DTV formats usually include both interlaced and progressive display methods. Progressive or non-interlaced video produces a higher quality image. Interlaced video suffers from flicker problems due to the full image not being displayed and from alignment problems where the odd lines do not exactly line up with the even lines. Such alignment problems can be particularly bad in video containing fast moving images.
- ProjectorProjectors fall into two categories, those that project the image onto the front (viewed) surface of a reflective screen and those that project onto the rear surface of a translucent screen. Both types can be based on CRTs, LCDs (liquid crystal displays), DMDs (digital micromirror device from Texas Instruments, also known as DLP) or some other technology. Of all of these, CRTs are the most improved with a line doubler. The effect on LCD and DMD projectors greatly depends on the make and model of the projector - with some there is a dramatic improvement, with others it is not as dramatic.
- Pulldown (3-2 Pulldown)One method of committing a 24 frame per second movie on film to 60 field per second or 60 frame per second video. Every other film frame is scanned three times and the intervening frames scanned twice to obtain video fields or frames. If you single step through a VCR recording of a movie, you will often see the three-two-three-two pattern.
- RCA Connection(RCA Plug, RCA Jack) Used for Composite Video signal interface, and Audio signal interface (R and L separate in stereo).
- Rear ProjectionProjecting an image through a translucent screen material with a special coating which allows an image to be projected through the screen, rather than onto the surface of the screen, for viewing from the opposite side. As opposed to front projection. The slide or film must be reversed, or a mirror must be used to correct the image for rear screen presentation. In some video or computer projectors, the image can be reversed electronically.
- ReceiverA device that captures an over the air broadcast, satellite, cable or microwave transmission, and presents it for listening, data processing, or viewing.
- Refresh RateThe vertical scan rate of a video display, or the number of times a second that a video display can paint an entire screen with a video signal. The standard refresh rate in the U.S. for video (television, DVD, VHS, laserdisc) is 60 Hz. The maximum vertical resolution of a video display can be determined by dividing the horizontal scan rate by the refresh rate.
- ResolutionThe density of lines and dots per line which make up a visual image. Usually, the higher the numbers, the sharper and more detailed the picture will be. In terms of DTV, maximum resolution refers to the number of horizontal scanning lines multiplied by the total number of pixels per line, called pixel density. VGA (Video Graphic Array) : 640 pixels x 480 pixels SVGA (Super VGA) : 800 pixels x 600 pixels XGA (eXtended GA) : 1024 pixels x 768 pixels SXGA (Super XGA) : 1280 pixels x 1024 pixels
- RS-232 InterfaceA serial communications interface between an electronic device and PC. The interface can be used for remote mouse control, operation by command panel, troubleshooting, transfering service data transfer, etc.
- S-VideoSeparated Video or Super-Video is a standard for video cabling that splits the information into two separate signals: one carries brightness (luminance) and the other carries color (chrominance). In contrast to composite video, S-Video has a sharper picture. Nowadays, DVD players, some VCRs, and many high-end televisions all support S-Video.
- SamplingThe process of converting an analog signal (such as a picture or a soundtrack) into digital form. In the case of a picture, a large number of small, evenly spaced areas are taken and each represented as one or more numbers for brightness (luminance) and color. These areas are referred to as picture elements or pixels. The more samples are taken, the more accurate (with higher resolution) an image can be reconstructed from the samples. For DVD, the image is 720 samples wide by 480 samples high for a total of 345,600 samples (may vary slightly). Even analog TV has sampling -- each scan line is a discrete (as in digital) sample in the vertical direction although it is continuous (analog) in the horizontal direction.
- ScalingThe reformatting of video or digital pictures to occupy a different number of scan lines or a different horizontal or vertical pixel count. Also referred to as "resampling". This is done to zoom an image on the screen without spreading out the existing scan lines, or to change the video from one format to another, for example HDTV to NTSC or NTSC to SECAM.
- SDTV (Standard Definition Television)Standard Definition TV is one of the new standards for broadcasting and receiving digital television (DTV). SDTV includes 480 lines in both interlaced and progressively scanned formats, (although the latter has recently been renamed EDTV or Enhanced Digital TV), and offers significant improvement over today's NTSC picture. The new DTV channel can be compressed to provide four, five or more SDTV programs within the same bandwidth required for one channel of NTSC television (the current U.S. standard).
- SECAMSequential Couleur avec Memoire is the television broadcast standard in France, the Middle East, and most of Eastern Europe. SECAM uses a similar timing and resolution to PAL, and is one of three main television standards throughout the world.
- Serial Digital Interface (SDI)Serial Digital Interface (SDI) is an SMPTE standard for digital video transmission over coaxial cable. The SDI signal can also contain up to four independent digital audio signals along with the video signal. Two variations of SDI standard exist, based on the data rate: standard-definition (SD)-SDI and high-definition (HD)-SDI. The SDI standard is widely used in broadcasting and the video production industry because of the ability to transmit video signals over long distances with no loss of information.
- Serial PortA data I/O port on the computer enabling other devices or computers to link with the computer. Also referred to as RS-232C or COM port.
- SMPTESociety of Motion Picture and Television Engineers
- SVGASuper VGA is an extension to the original VGA standard, and allows resolutions of 800x600.
- SXGASuper XGA resolution is 1280x1024 pixels
- SXGA+Super XGA+ resolution is 1400x1050 pixels. It is a hybrid between SXGA and UXGA found on some LCD screens for laptop PCs.
- Television DisplaysThere are several types of display devices that can be used as a television. Direct View Televisions are based on large CRTs (cathode ray tubes) that project the image onto a the surface of a phosphor-lined glass screen which you view directly, hence the name. Projector TVs fall into two categories, those that project the image onto the front (viewed) surface of a reflective screen and those that project onto the rear surface of a translucent screen. Both types can be based on CRTs, LCDs (liquid crystal displays), DMDs (digital micromirror device, also known as DLP) or some other technology. Flat Panel Televisions are typically based on plasma or LCD technology, and can be thought of as inherently progressive in that the entire image is drawn at one time with no interlacing of odd and even lines. Because of this capability, most of these devices are capable of acting as computer monitors as well as being used as televisions. Large Computer Monitors can be used as televisions, but a big drawback is that they are typically not as bright as televisions. In addition, with computer monitors, you won't have access to all of the fancy Picture-in-Picture, stereo audio and other features typically found in today's TVs.
- TV TunerTV sets all come with built in tuners, which select the specified channel out of all of the channels broadcast, and convert it into a baseband (non-modulated) video signal for display. Plasma Display TVs may require a separate tuner, which may be a satellite or a cable set-top box.
- UnderscanCondition when the picture size is adjusted so that strips of unused screen area are along all borders. Computer users sometimes leave their monitors adjusted this way to guarantee that material such as the "start button" in the lower corner of the Windows screen does not disappear beyond the edge. Also on some TV sets the edges of the picture suffer distortion when extended all the way to the picture tube edge. See also overscan.
- UpconvertTo convert a video format to a higher resolution or higher quality form. For high-definition television, it is used to describe the process of reformatting a SDTV (480i/480p) signal to an HDTV format (1080i). This may not actually increase picture resolution, but allows the program to be accepted through the set's HDTV inputs.
- UXGAUltra XGA - describes 1600x1200 pixel resolution.
- Vertical ResolutionNumber of horizontal lines that can be output by a video display. Higher resolutions result in better quality pictures. Television resolution is often stated in vertical resolution, for example the NTSC (analog) television standard used in the United States has a vertical resolution of 525 - there are 525 horizontal lines to make up the image. It should be noted that DVD and some digital broadcasts (satellite, digital cable) are the only sources that actually provide the maximum vertical resolution (or at least close to it). Vertical resolution for high definition television is set at either 1080 lines (1080i = 1080 interlaced lines) or 720 lines (720p = 720 non-interlaced lines).
- VESAVideo Electronics Standards Association - An association whose mission is to promote and develop timely, relevant, open display and display interface standards, ensuring interoperability, and encouraging innovation and market growth.
- VGAVideo Graphics Array is a video standard that allows for resolutions up to 640x480 with up to 16 colors, or 320x200 resolution with 256 colors. Today, however, VGA refers to a 640x480 format. Higher resolutions have now mostly replaced VGA, but VGA compatibility remains an important part of most graphics cards.
- Video ScalerElectronic device used to perform scaling, usually with a choice of scalings not necessarily an even multiple or fraction of the original scan line or pixel count.
- Wide ScreenRefers to a video program whose picture has a wider aspect ratio than 4:3.
- XGAAn analog computer video format with 768 visible scan lines each normally representing 1024 pixels across.