platinumsword

A work in progress.

This Glossary is a concise collection of some of the terminology that you may confront; it is not intended to be a complete compendium of technical terms.


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480i

480i is the shorthand name for a video mode. The i, which is sometimes uppercase, stands for interlaced, the 480 for a vertical frame resolution of 480 lines. The digitally transmitted horizontal resolution is usually 720 or 704 pixels with an aspect ratio of 4:3 and therefore a display resolution of 640 × 480 (VGA); that is standard-definition television (SDTV).

The field rate (not the frame rate) is usually (60/1.001) 59.94 hertz for color TV and can be rounded up to 60 Hz. There are several conventions for written shorthands for the combination of resolution and rate: 480i60, 480i/60 (EBU) and 480/60i. 480i is usually used in countries that conventionally use NTSC (North America, Japan), because the 525 transmitted lines at 60 hertz of analogue NTSC contain 480 visible ones. 480i can be transported by all major digital television formats, ATSC, DVB and ISDB. NTSC DVDs use 480i when high motion is desired, but for movies 24 progressive frames per second (480p) are used instead. The 480i resolution is used in most standard-definition TVs.

480p

480p is the shorthand name for a video display resolution. The p stands for progressive scan, i.e. non-interlaced, while the 480 denotes a vertical resolution of 480 vertical scanning lines, usually with a horizontal resolution of 640 pixels and 4:3 aspect ratio on standard-definition television (SDTV), or a horizontal resolution of 854 pixels and 16:9 aspect ratio on high-definition television (HDTV). 480p is not high enough to qualify as HDTV; it is considered Enhanced-definition television (EDTV). The frame rate is usually 30 or 60 hertz and can be given explicitly after the letter.

720i

720i is a non-standard term applied to HDTV Broadcast. Like 720p, it features a resolution of 1280x720 pixels, however, it instead produces an interlaced image as opposed to a progressive image. This is similar in manner to how 1080i is 1920x1080 pixels, but interlaced as opposed to 1080p which is progressive.

The most common practical usage of 720i is that by Satellite broadcasters. Echostar/ DISH Network is transmitting some HDTV channels in the interlaced format consisting of 720 lines as a bandwidth saving measure. The 720i format is then converted to the receiver's selected output resolution (720p or 1080i) for presentation to the display.

720p

720p is the shorthand name for a category of HDTV video modes. The number 720 stands for 720 lines of vertical display resolution, while the letter p stands for progressive scan or non-interlaced. When broadcast at 60 frames per second, 720p features the highest temporal (motion) resolution possible under the ATSC standard. Progressive scanning reduces the need to prevent flicker by filtering out fine details, so spatial (sharpness) resolution is much closer to 1080i than the number of scan lines would suggest.

720p assumes a widescreen aspect ratio of 16:9, and a horizontal resolution of 1280 pixels for a total of about 0.92 million pixels. The frame rate (in this case equal to the field rate) can be either implied by the context or specified in hertz after the letter p. The five 720p frame rates in common use are 24, 25, 30, 50 and 60 Hz (or fps).

1080i

1080i is a shorthand name for a category of video modes. The number 1080 stands for 1080 lines of vertical resolution, while the letter i stands for interlaced or non-progressive scan. 1080i is a high-definition television (HDTV) video mode. The term usually assumes a widescreen aspect ratio of 16:9, implying a horizontal resolution of 1920 pixels and a frame resolution of 1920 × 1080 or about 2.07 million pixels. The frame rate in hertz can be either implied by the context or specified after the letter i. The two frame rates in common use are 25 and 30 Hz, with the former (1080i25) generally being used in traditional PAL and SECAM countries (Europe, Australia, much of Asia, Africa), and the latter (1080i30) being used in traditional NTSC countries (e.g. United States, Canada and Japan).

1080p

1080p is the shorthand name for a category of display resolutions. The number "1080" represents 1,080 lines of vertical resolution, while the letter p stands for progressive scan (meaning the image is not interlaced). 1080p is considered an HDTV video mode. The term usually assumes a widescreen aspect ratio of 16:9, implying a horizontal resolution of 1920 pixels. This creates a frame resolution of 1920×1080, or 2,073,600 pixels in total. The frame rate in Hertz can be either implied by the context or specified after the letter p, such as 1080p30, meaning 30 Hz.

4:3

Standard "square" NTSC TV screen-size aspect ratio of 4 arbitrary units wide by 3 arbitrary units high; often expressed as 4x3 or 4 by 3. It was originally known as the Academy Ratio (as in Academy of Motion Picture Arts and Sciences, the film industry organization that awards the Oscars) prior to 1954 and the introduction of wide-screen aspect-ratio film formats; also known in the film world as 1.33:1.

16:9

16:9 (generally named as: "Sixteen-by-Nine") is the international standard format of HDTV as used in Australia, Canada, Japan, South Korea, and the United States, as well as in Europe on HDTV and non-HD widescreen television (EDTV) PALplus. Japan's Hi-Vision originally started with a 5:3 ratio but converted when the international standards group introduced a wider ratio of 5 1/3 to 3 (16:9), invented by Kerns H. Powers in the 1984. The 1.78:1 aspect ratio was the compromise between the 35 mm US and UK widescreen standard (1.85:1) and the 35 mm European widescreen standard (1.66:1)

2:2 pull-down

Method for transferring 24 frame-per-second film to PAL/SECAM video running at 25 frames per second.

2:3 pull-down detection

Also (and less accurately) called 3:2 pull-down; digital technology developed by Faroudja to accurately convert and display content originally on celluloid film, which runs at 24 frames per second (fps) compared to the 30fps rate of television. It is found in many DVD players and DTVs.

2K

2K is a term, like SD and HD, used in today’s post-production environment to describe a particular image size and quality of data. 2K data exceeds our pre-existing television broadcast standards for both SD and HD and is therefore most commonly associated with traditional cinema and the emerging digital cinema initiative. When working with data for eventual cinematic projection, FX work or digital intermediate purposes, 2K is usually defined as 2048x1556 pixels. This size represents the “full” size of the 35mm film between the sprockets. Therefore the result, 2048x1556 pixels, appears as a 4x3 image when compared to an HD image which is typically 16x9. In 2K, other image sizes can be derived from this 2048x1556 source by taking a cropped portion of the image for use. For a traditional cinematic projection scenario, the final delivery of this 2048x1556 data is onto 35mm film. The film undergoes photochemical and mechanical processes before the image reaches the screen. The other common size attributed to 2K is 2048x1080; this is the standard to which digital cinema currently adheres. Most digital cinema projectors have this 2048x1080 image size as a supported resolution and in many cases, as a maximum resolution. Here the data at 2048x1080 need not undergo a photochemical process; it can stay data for its path to projection.

4k

Usually defined as 4096 x 4097, However, the vertical resolution of the K’s can vary by quite a bit. A 4K scan of the entire 35mm film frame will be 4096x3112. A 4K image for a 1.85:1 output will be 4096x2214. A 4K 2.39:1 output could be 4096x3112 or 4096x1714 depending on whether it is anamorphic or not. To simplify things just remember this, 4K has four times the number of pixels as 2K for the same aspect ratio. 2K has 13% more pixels than HD. In all other areas, such as bit depth and color format, 4K, 2K, and HD RGB are identical. 4K has many advantages, and may someday become the standard for digital intermediate work, but with today’s technology the costs of working in 4K often exceed the benefits.

5.1

5.1 is a surround sound setup that consists of five speakers that emit five audio channels--center, right, left, and surround sound right and left--and one subwoofer speaker that emits a low-frequency sound.

6.1

6.1 is a surround sound setup that consists of six speakers that emit six audio channels--center, right, left, and surround sound right and left, and rear--and one subwoofer speaker that emits a low-frequency sound.

7.1

7.1 is a surround sound setup that consists of seven speakers which emit seven audio channels--center, right, left, and surround sound right and left, and two in the rear--and one subwoofer speaker that emits a low-frequency sound.

5C DTCP

5 company Digital Transmission Content Protection. An HDTV copy-protection encryption method for devices connected via FireWire, this allows one of three copy states: copy always (all ATSC broadcast and "in the clear" QAM cable broadcasts); copy once (premium cable); and, copy never (pay per view, video-on-demand). Bidirectional system requires 5C chips in every device in an A/V system (in other words, a set-top box, a TV, and so on); the TV "requests" acknowledgment before allowing the signal to be viewed or recorded. Proposed and sponsored by Hitachi, Intel, Matsushita (Panasonic), Sony, and Toshiba--the five companies.

3DES

A data encryption standard. As its name suggests, 3DES is a three-step data encryption algorithm that evolved from DES. 3DES provides greater security than DES because it encrypts, decrypts, and encrypts the data using three keys instead of just one. The size of a 3DES key is also three times bigger: 168 bits to 56 bits for DES.

A


AC-3

The 5.1-channel sound system specified in the Standard for Digital-HDTV. Also known as "Dolby Digital," AC-3 delivers CD-quality digital audio and provides five full-bandwidth channels for front left, front right, center, surround left and surround right speakers, plus an LFE (low frequency effect) subwoofer, for a total of 5.1 channels.

A-Weighting

Measurement based roughly on the uneven frequency sensitivity of the human ear. The influences of low and high frequencies are reduced in comparison to midrange frequencies because people are most sensitive to midrange sounds.

AACS

Advanced Access Content System, the content protection system used by BD-ROM.

Academy Curve

An intentional roll-off in a theatrical system's playback response above ~2kHz (to -18dB at 8kHz) to minimize noise in mono optical tracks. Some (many) transfers to home video of mono movies have neglected to add the Academy filter during transfer, giving many old movies a screechy sound they were never intended to have. A few home processors have an Academy filter option, making them a must for old-movie buffs. Has been used since 1938.

ACATS

Advisory Committee on Advanced Television Service; special FCC committee that recommended DTV standards in 1997.

Acoustic Suspension

A sealed speaker enclosure that uses the air trapped in the cabinet as a reinforcing spring to help control the motion of the woofer(s).

Active Format Description

(AFD) is a signal that broadcasters can transmit with the picture to enable both 4:3 and 16:9 television sets to optimally present pictures transmitted in either format. Essentially, AFD is a standard set of codes sent in the MPEG video stream that provides information to the decoder about where in the coded picture the active video is. They can then use this information, together with knowledge of the display shape and user preferences, to choose a presentation mode.

Advanced Content

One of two HD DVD specifications defined by the DVD Forum. Advanced Content enables a majority of the new capabilities in the HD DVD format.

AES

The Advanced Encryption Standard is a data encryption scheme that trumps DES and even 3DES by using three different key sizes (128-bit, 192-bit, and 256-bit) but only one encryption step to encrypt data in 128-bit blocks. Based upon the Rijndael (pronounced "rain doll" or "Rhine Dahl") algorithm created by Joan Daemen and Vincent Rijmen of Belgium, AES was adopted by the U.S. government in 2002 as the encryption standard for protecting sensitive but unclassified electronic data. With the arrival of AES, the United States officially phased out DES except for in legacy systems, but as of this writing, 3DES is still an acceptable alternative.

Advanced Television Systems Committee (ATSC)

The ATSC is the committee responsible for developing and establishing Digital-HDTV Standards; as well as all (18) formats of Digital TV.

A/D

Analog to digital conversion (or converter). Used at transmission end of broadcast.

Addressable Resolution

The highest resolution signal that a display device (TV or monitor) can accept. Caution: Consumers should be aware however, that although a particular device (Digital-HDTV) is able to receive the resolution, it may not be capable of displaying it.

After Color Temp

It is the color temperature at a given brightness level after grayscale calibration. Usually expressed in degrees Kelvin ideally as close to 6,500K as possible.

After Grayscale Variation

After calibration, the average amount of variation from an ideal of 6,500K, measured over the entire range of the grayscale--typically 20 to 100 IRE in 10-IRE increments.

Analog Hole

A movie industry term for the potential to create high quality copies of copy protected digital content by digitizing the analog output that is unprotected. Digital streams can be copy protected using encryption whereas analog signals cannot.

Anamorphic Widescreen

Adopted from the film technique of shooting a wide-screen image on a square 35mm frame, it's the process of compressing wide-screen images to fit into the squarer standard 4:3 television signal. The images are then expanded for viewing in their original format on a wide-screen display device. Wide-screen or letterboxed DVDs that are not anamorphic have less detail when projected on a wide-screen monitor. In other words, a nonanamorphic wide-screen DVD is designed to be shown letterboxed on a standard "square" TV but appears with a black box all around the image when shown on a larger 16:9 wide-screen TV. To fill a 16:9 screen, a nonanamorphic DVD has to be blown up, resulting in loss of resolution and detail. Conversely, a DVD that is anamorphic, enhanced for 16:9, or enhanced for wide-screen delivers 33 percent more resolution than regular letterboxed transfers, is designed to be shown on a 16:9 TV, and does not need to be blown up. When one of these DVDs is shown on a "square" TV, it is often subject to anamorphic down conversion artifacts unless the TV has a vertical compression feature.

ANSI Lumens

Light-output specification set in 1993 used mainly to measure brightness of front-projection televisions; more exact than undefined lumens. The average 7-inch, CRT front-projection television is capable of between 150 and 175 ANSI lumens, while 9-inch CRT sets emit between 200 and 240. DLP and LCD projectors range from 600 to 7,000, depending on the model.

Aperture

A device that controls amount of light admitted.

Aperture Correction

Compensation for the loss in sharpness of detail because of the finite dimensions of the image elements or the dot-pitch of the monitor.

Artifacts

Unwanted visible effects in the picture created by disturbances in the transmission or image processing, such as 'edge crawl' or 'hanging dots' in analog pictures, or 'pixilation' in digital pictures.

Aspect Ratio

Aspect ratios are mathematically expressed as x:y. The most common aspect ratios used today in the presentation of films in movie theaters are 1.85:1 and 2.39:1. Two common video graphic aspect ratios are 4:3 (1.33:1), universal for standard-definition video formats, and 16:9 (1.78:1), universal to high-definition television and European digital television. Other cinema and video aspect ratios exist, but are used infrequently.

Academy - 1.33:1 (current) or 1.37:1 (before a soundtrack is added)

The Academy ratio (1.37:1 before a soundtrack was incorporated onto the film) was the primary original aspect ratio. Most movies (if not all) that were released before The Robe (the first movie to be shown in widescreen) were shown in this ratio.

When televisions first came on the scene, they were (and still are) designed with an aspect ratio matching the Academy ratio so that movies would be shown in the same way as in the theatres. Movies that were filmed in an Academy ratio will not have a "widescreen" version because they fit perfectly on the TV. Such movies include The Wizard of Oz, Casablanca, Citizen Kane, and many, many others.

Cinemascope - 2.35:1 to 2.55:1

This was once the most commonly used method of filming movies because its only major requirement was a special CinemaScope projector lens. This lens was and still is available at many movie theatres. CinemaScope was originally created by 20th Century Fox, but it is no longer in use in its original format.

The 2.55:1 ratio was pretty much dead by 1957 when the last holdout, Fox, adopted magoptical over mag-only prints. From that point until the early 1970s a standard of 2.35:1 was used; however, there is usually slight matting in theatres which results in a theatrical aspect ratio closer to 2.40:1. All of the Star Wars movies and even the 1997 animated version of Anastasia were filmed in CinemaScope, as were classics like The Robe and 20,000 Leagues Under the Sea.

Cinerama - 2.35:1 when transferred, 2.60:1 originally

This method of filming actually used three cameras, after which the three images were interlocked together. This created an extremely wide presentation of up to 2.60:1. However, any transfer to video would be from a 35mm anamorphic reduction print. Therefore, home video transfers have a 2.35:1 ratio. Several movies were filmed in Cinerama, including How the West Was Won, The Wonderful World of The Brothers Grimm, and Seven Wonders of the World.

Cinerama also required the screen onto which the image was projected to be deeply curved or else the resulting picture would suffer from severe distortions as a result of projecting at different angles. (This is the "trapezoid" effect that you get when a projector is not at an exact angle to the screen.) Therefore, it is not really possible to make a "widescreen" version of a Cinerama film suitable for viewing on a television unless some form of corrections are applied to eliminate the distortion.

Hard Matte / Open Matte - 1.66:1 to 1.85:1

Both hard and soft matting involves filming a movie onto a 1.33:1 frame and matting the frame during post-production to get its intended aspect ratio. The main difference between the two is how the movie is processed for home viewing.

Most open matte films have the mattes removed when transfered to a "full frame" home video release. This can dramatically increase the potential for unexpected material such as boom mikes to appear in the home video version. In fact, some directors simply placed cardboard on the monitors to simulate the matted theatrical version. This would have made them unaware during filming if the boom mikes and so forth were actually on the frame because the cardboard was blocking that part out.

Hard matted films are "locked" to their aspect ratio and are subjected to the pan-and-scan process for the "full frame" home video release. This results in the loss of visual information on the sides of the frame. Movies such as Memphis Belle are hard matted.

Panavision - 2.40:1 (anamorphic) / Various (flat)

The Panavision company is now the most successful maker and distributor of lenses and filming equipment. In the 1970s their Panavision lenses became the "standard" for widescreen and non-widescreen movies. Panavision still makes or sells the lenses for most of the major studio productions today, including lenses for films made with matting as opposed to true widescreen. These matted films are not necessarily 2.40:1, but are most likely 1.85:1.

Because Panavision now represents the manufacturer and distributor more than the filming process, it is not uncommon to see that many television shows are filmed with Panavision lenses. Therefore, it is important to note that "Filmed with Panavision cameras and lenses" does not automatically constitute a widescreen process.

Super 35 - Various

This process does not involve widescreen lenses, but rather it involves framing the picture to fit the ratio of the screen. The top and bottom of the frame are "matted" out and removed from the picture completely, resulting in a rectangular picture.

Super35 movies are filmed using flat lenses. Using an optical printer, the "interpositive" image is then contact-printed to produce an "internegative" anamorphic release print. As a result, an anamorphic image from a Super35 original tends to have a "gritty but sharp" look that is "harder" in a way than an anamorphic image, which has a "smooth" look.

Many movies made in Super35 are transferred to video with the top and bottom of the frame restored, so that you actually see more of the picture on video than you did in the theater. However, scenes which include special effects in them are almost always filmed hard-matted in the appropriate widescreen ratio and therefore must be subjected to the pan-and-scan process.

Super Panavision - 2.20:1

Super Panavision 70 was a 70mm version of the Panavision process meant to compete directly with the 70mm Todd-AO process. Super Panavision 70 has also been known as Panavision 70, Super Panavision, Panavision, and Panavision Super 70. With an anamorphic lens, SP70 movies could have a final aspect ratio of 2.76:1. Famous movies that were filmed in Super Panavision 70 are My Fair Lady, 2001: A Space Odyssey, and Chitty Chitty Bang Bang.

Technirama - 2.20:1 (70mm) / 2.35:1 (35mm)

This process was developed by the Technicolor Corporation, as a way to continue using its three-strip Technicolor cameras. It required both a specially developed camera to run the film sideways (like VistaVision) with a widescreen lens (like CinemaScope).

Technirama was shot with VistaVision cameras and an anamorphic lens squeezing the image by 25%. The entire 1.5:1 image area was then either optically unsqueezed to 70mm yielding a 2.21:1 aspect ratio, or given an additional squeeze to 35mm 2.35:1 4-perforated (four sprocket holes per frame) Panavision. For purposes of video transfer only an A/R of 2.35:1 would apply since there was never a 65/70mm negative involved in the process.


Todd-AO - 2.20:1 (during filming) / 2.35:1 (final 35mm print)

This process uses a 65mm negative printed onto 70mm film, with a six-track soundtrack, producing a very high quality picture. The original filming was done in an aspect ratio of 2.2:1; however, during the printing to 70mm film, the aspect ratio ended up being closer to a 2.35:1 aspect ratio. The original Todd-AO format also was shot at 30 frames per second, as opposed to the current standard of 24 frames per second.

Many of the great epics and musicals of the 50s and 60s used this format.

Ultra Panavision 70 - 2.76:1 (65/70mm) / 2.35:1 (35mm)

Ultra Panavision 70, created by MGM, was created to compensate a shortcoming with the original CinemaScope format called "CinemaScope mumps" where close-up images in the center of the screen did not get compressed properly. UP70 used anamorphic lenses and a consistent frame rate of 24 frames per second, which was not yet a standard among the various film formats. This was done with a camera that MGM called the "MGM Camera 65".

UP70 was used to film some of the most popular movies in movie history, like Ben Hur, Mutiny on the Bounty, and It's a Mad, Mad, Mad, Mad World.

VistaVision - 1.66:1 / 1.85:1 / 2.0:1

This system was more flexible than others, allowing for more aspect ratios. But Paramount's specs always referenced a preferred A/R of 1.85:1. All VV prints were hard matted to around 1.66:1 to allow some flexibility in framing.

VistaVision movies were filmed with a specially designed camera that was mounted on its side. This special filming method required a special projector, but its image quality was better than standard 35mm.

Movies that are shot in VistaVision were photographed on a double-width frame of 35mm running right to left horizontally. The films were generally "reduction printed" to 35mm 4-perforated (four sprocket holes per frame) in dye-transfer Technicolor and projected with a 1.85:1 ratio. The image area was extracted optically from the full frame. For some special venues the double-frame 35mm film was cropped to 1.85:1 during projection. VistaVision movies include Vertigo, North By Northwest, and White Christmas.

Attenuate

To turn down, reduce, decrease the level of; the opposite of boost.

ATV

"Advanced Television" is an earlier term used to describe the development and advance applications of digital television, now
simply referred to as DTV.

B

Balanced Input

A connection with three conductors: two identical signal conductors that are 180 degrees out of phase with each other, and one ground. This type of connection is very resistant to line noise.

Bandpass

A two-part filter that cuts both higher and lower frequencies around a center band. A bandpass enclosure cuts high frequencies by acoustic cancellation and low frequencies by natural physical limitations on bass response.

Bandwidth

This term describes data-carrying capacity--in other words, how much (and how fast) data flows on a given transmission path.

Barn Doors

A term used in television production to describe the effect that occurs when a 4:3 image is viewed on a 16:9 screen. When this happens, viewers see black bars on the sides of the screen or "barn doors."

Bass

Low frequencies; those below approximately 200 Hz.

Before Color Temp

The color temperature at a given brightness level before grayscale calibration. Usually expressed in degrees Kelvin; ideally as close to 6,500K as possible.

Before Grayscale Variation

Before calibration, using the television's best available presets, the average amount of variation from an ideal of 6,500K, measured over the entire range of the grayscale--typically 20 to 100 IRE in 10-IRE increments.

Bezel

The frame around a CRT or LCD screen.

Bipolar

1) The condition of possessing two pole sets. In a conventional (non-FET) transistor, one pole set exists between the base and collector, and the other pole set exists between the base and emitter.

2) Speakers that consist of two driver arrays facing opposite directions and wired in electrical phase with one another to create a more diffuse soundstage.

Bit Rate

A range of frequencies used to transmit information such as picture and sound. For TV broadcasters, the FCC has allocated 6 MHz for each channel. For DTV, the maximum bit rate possible within the bandwidth is 19.4 Mbps, which is one HDTV channel. SDTV has a lower bit rate; therefore the bandwidth can accommodate more than one channel.

Bi-Wiring

A method of connecting an amplifier or receiver to a speaker in which separate wires are run between the amp and the woofer and the amp and the tweeter.

Black Level

Black level is the measurement of the deepest level of black as configured in a TV’s settings. Most TVs need to be calibrated so that the black level is a true black; otherwise the colors will be muddled.

Blu-ray

Blu-ray disc is a next-generation entertainment optical storage format. Though it resembles a DVD, a Blu-ray disc has a current maximum capacity of 50 GB and can only be played on a player with a Blu-ray drive. This produces a progressive video image resolution of up to 1920 x 1080, better known as 1080p--the best picture quality currently available. Blu-ray's picture presentation even tops that of an HDTV broadcast, and its hard coating is also much more resistant to scratches and fingerprints than DVDs or CDs.

Boost

To increase, make louder or brighter; opposite of attenuate.

Bridging

Combining two channels of an amplifier to make one channel that's more powerful. One channel amplifies the positive portion of an audio signal and the other channel amplifies the negative portion, which are then combined at the output.

Brightness

A measurement of the light output that can be displayed. The lower the brightness, the more that ambient room light will interfere with a display. Measured in nits.

C

CableCARD

CableCARD is an actual credit card-sized card that cable television companies provide to their users so that they can receive high-definition television programming. The card is fitted into an HD-ready TV. The term can also refer to systems of giving their users high-definition TV without an actual card that some cable companies provide.

Calibration

To properly enjoy television or movies in high definition, your new HDTV needs to be calibrated so that the black levels are true black and the white levels are true white--this keeps the colors from getting muddled. You can do this yourself or hire a professional to calibrate your HDTV for you.

Candela

The candela is the luminous intensity, in a given direction, of a source that emits monochromatic radiation.

Cascading Crossovers

Two crossovers used in series on the same signal in the same frequency range causing greater attenuation of the out-of-band signal. For example,using the crossover in a receiver's bass management setting and the one in a subwoofer simultaneously will create an exaggerated loss of signal.


Chrominance

Technical name for the TV signal that carries the color information (red, green, and blue) needed to produce a color picture; often called chroma.

Chrominance-To-Luminance Delay

Video artifact caused by the color signal lagging the brightness signal; appears as color smearing on the left edges of some onscreen objects; easiest to see with a test pattern that has a colored vertical stripe running down the middle of a white field.

Coaxial Cables: Analog and Digital

Coaxial cables are analog and are used to carry high-frequency signals over long distances and are shielded by three layers to prevent accumulating background noise over the journey. They are still in wide use today for transmitting radio communication, cable television, and Internet.

Digital coaxial cables are used for connecting things over short distances, such as those between DVD players and TVs. They are falling out of favor in preference of component video cables and, even more so, HDMI cables.

Color Balance

A CRT monitor uses three electron guns (red, green, and blue) to excite the phosphors that make up the pixels in an image. Color balance refers to the relative strength of the signal from each of the three guns. If the blue gun is turned up higher than the other two, for example, you will see a bluish tint on the screen. Many monitors provide color-adjustment controls that allow you to adjust the color balance.

Color Decoder

Component in all televisions that translates color-signal information from the source for display on the TV. ATSC and NTSC require two separate decoder matrices. Practically speaking, many color decoders accentuate red to compensate for a blue color temperature, a phenomenon known as red push.

Color Purity

Because CRT monitors use electromagnetism to control their electron guns, magnetic fields build up within the monitor and cause distortions that appear as colored patches on the screen. A monitor has good color purity if no such discolorations are visible (they are easiest to see on a white background). The magnetic fields that cause problems with color purity can sometimes be eliminated by degaussing.

Color saturation

A monitor with good color saturation can display subtle color changes distinctly so that the human eye perceives the differences. If similar colors blend together or if colors appear dark, they are oversaturated; colors that appear washed-out and faded are undersaturated.

Color Temperature

Sometimes called white balance and expressed in degrees Kelvin or just Kelvins, this is the color of gray at different levels from black to white. Since color information overlays the black-and-white information in a TV signal, color temperature affects the entire range of color. The National Television Standards Committee (NTSC) standard is 6,500K, but typically manufacturers ship their TVs with color temperatures ranging from about 7,000K to 12,000K, on the blue side of the color spectrum, to make sets as bright as possible to stand out on a brightly lit showroom sales floor. Some sets have a selectable color temperature.

Color Tracking

Each pixel on a CRT monitor's screen consists of red, green, and blue spots of phosphor, each lit up by a separate electron gun. Color tracking refers to a monitor's ability to keep all three electron guns operating at equal strength when displaying different brightness levels. In practice, one gun tends to overpower the other two, resulting in slight reddish, greenish, or bluish hues that are visible in dark-gray areas of an image.

Color Wheel

A device used in single-chip DLP front- and rear-projection that filters light into red, green, and blue components, which are then combined to create a picture. The color wheel is positioned between the lamp and the screen, and it spins faster than the eye can see to select the correct color. The speed of the color wheel is a significant factor in the prevalence of the rainbow effect.

Comb Filter

Component in all televisions that separates the chrominance and luminance from one another in composite-video connections. Good comb filtering enhances fine detail, cleans up image outlines, and eliminates most extraneous colors. Comb filters do not affect S-Video, component-video or digital-video connections.

Component Video

The elements that make up a video signal, consisting of luminance and two separate chrominance signals, expressed either as Y R-Y B-Y or Y Pb Pr.

Composite Video

A type of video signal in which all the necessary video information is combined into one signal. This is the type of signal used for broadcast TV in the United States. Most computer monitors use RGB video, in which the red, blue, and green signals are sent separately to produce a sharper image.

Compression

Compression: Taking a large amount of information/data, and ‘re-writing’ it so that the new data takes up less space (on a Blu-ray or CD, for examples). This is known as “compressing” the data (or “encoding”). Before the data can be used again, it must be “decompressed” (or “decoded”). Some Blu-ray players can decompress data on their own – then send it to the receiver (as uncompressed PCM) to play it. Some must send the compressed data to an audio receiver first, and the audio receiver must then perform the decompression and play the audio. This depends on what compression method has been used, and if that player is capable of performing the decompression itself. Additionally, not all compression methods are equal. Some processes allow for exact copies of the original audio to be produced (Lossless), others do not produce exact copies of the original data and therefore some information is lost (Lossy). Some of the ‘styles’ of audio compression include: Dolby Digital, DTS, Dolby TrueHD, DTS-HD Master Audio (MA). See Bitstream. See PCM. See Lossy. See Lossless.

Contrast Ratio

The difference in light intensity between the brightest white and the darkest black that a display device can produce. A higher the contrast ratio is better than a lower one.

Convergence

Color CRTs rely on three separate electrical beams to project simultaneous red, green, and blue images; these combine to form a full-color image. If these beams are not precisely aligned, the red, green, and blue portions of the image may not overlap correctly, degrading the overall image quality. When the three beams converge correctly at all points on the display, you get a perfect image.

Crossover

A component that divides an audio signal into two or more ranges by frequency, sending, for example, low frequencies to one output and high frequencies to another. An active crossover is powered and divides the line-level audio signal prior to amplification. A passive crossover uses no external power supply and may be used either at line level or, more commonly, at speaker level to divide the signal after amplification and send the low frequencies to the woofer and the high frequencies to the tweeter.

Crossover Frequency

The frequency at which an audio signal is divided. 80 Hz is a typical subwoofer crossover point and is the recommended crossover point in theatrical and home THX systems. Frequencies below 80 Hz are sent to the subwoofer; signals above 80 Hz are sent to the main speakers.

Crossover Slope

The rate of attenuation expressed in decibels of change for every octave away from the crossover frequency.


D

Damping

Of or pertaining to the control of vibration by electrical or mechanical means.

Damping Material

Any material that absorbs sound waves and eliminates acoustic energy by converting it into a different form. Fibrous material, for example, turns acoustic energy into heat via friction.

D'Appolito

Vertically symmetrical driver array. Typically consists of a tweeter mounted between two woofers. Creates a more-vertically directional sound with evenly spaced lobes in the off-axis response when compared with asymmetrical driver arrays.

DBS

Abbreviation of "Digital Broadcast Satellite" - refers to digital TV transmissions via satellite.
Defeatable edge enhancement

Ability of a TV to not introduce any extra edge enhancement.

Decibel (dB)

A logarithmic measurement unit that describes a sound's relative loudness, though it can also be used to describe the relative difference between two power levels. A decibel is one tenth of a Bel. In sound, decibels generally measure a scale from 0 (the threshold of hearing) to 120-140 dB (the threshold of pain). A 3dB difference equates to a doubling of power. A 10dB difference is required to double the subjective volume. A 1dB difference over a broad frequency range is noticeable to most people, while a 0.2dB difference can affect the subjective impression of a sound.

Deep Color

Deep Color refers to the use of various color depths in displays, up from the 24­bit depths in previous versions of the HDMI specification. This extra bit depth allows HDTV’s and other displays go from millions of colors to billions of colors and eliminate on ­screen color banding for smooth tonal transitions and subtle gradations between colors. The increased contrast ratio can represent many times more shades of gray between black and white. Also Deep Color increases the number of available colors within the boundaries defined by the RGB or YCbCr color space.

Degaussing

The earth's natural magnetism can cause unwanted magnetic fields to build up inside a monitor, causing a loss of color purity. A monitor's degaussing control removes these stray fields.

Delay

The time difference between a sonic event and its perception at the listening position (sound traveling through space is delayed according to the distance it travels). People perceive spaciousness by the delay between the arrival of direct and reflected sound (larger spaces cause longer delays).

Diaphragm

The part of a dynamic loudspeaker attached to the voice coil that produces sound. It usually has the shape of a cone or dome.

Diffusion

In audio, the scattering of sound waves, reducing the sense of localization. In video, the scattering of light waves, reducing hot spotting, as in a diffusion screen.

Diffusor

Acoustical treatment device that preserves sound energy by reflecting it evenly in multiple directions, as opposed to a flat surface, which reflects a majority of the sound energy in one direction.

Digital Intermediate (often abbreviated as DI)

Describes the process of digitizing a motion picture and manipulating color and other image characteristics to change the look, and is usually the final creative adjustment to a movie before distribution in theaters. It is distinguished from the telecine process in which film is scanned and color is manipulated but only intended for video and television distribution. A digital intermediate is also customarily done at higher resolution and with greater color fidelity than telecine transfers and utilizes only digital tools (no analog video devices).

Digital Cable Ready

Official term for an HDTV that conforms to the plug-and-play digital cable TV standard using POD (point of deployment) access cards, also called CableCARDs. With cable systems that comply with the standard, users can plug the cable directly into an HDTV set, then enjoy HDTV and digital cable without having to use a separate set-top box. Sets with interactive functionality are labeled Interactive Digital Cable Ready.

Digital Comb Filter

Device that separates the luminance and chrominance parts of a video signal in the digital domain, which provides enhanced color purity and reduced dot crawl over the analog variety.

Digital Television (DTV)

Refers to all formats of digital television, including high definition television (HDTV), and standard definition television (SDTV). Also referred to as ATV (Advanced TV)

D-ILA

Direct-drive Image Light Amplifier LCoS-based rear-projection technology developed and used by JVC. In its rear-projection products, the company calls the technology HD-ILA.

Dipole

Speakers with drivers on opposite faces that are wired electrically out of phase, creating an area of cancellation to the sides. Recommended by THX for use as surround speakers, with null directed at the listener to create a more ambient and non-localizable effect.

Direct-Stream Digital

A format for encoding high-resolution audio signals. It uses a 1-bit encoder with a sampling rate of 2,822,400 samples per second (verses 44,100 for CD). Used to encode six high-resolution channels on SACD.

Direct-View Television

Display whose image is created on the surface from which it is viewed.

Display Size

A display's length (in inches or centimeters) taken diagonally from one corner to the opposite corner. Unless it specifically states viewable screen area, a CRT's measurement encompasses the full face of the picture tube, including the part concealed by the bezel. On an LCD, only the viewable screen is measured.

Dithering

Creating the illusion of new colors and shades by varying the pattern of dots.

DLP

Digital light processing. A micro display technology invented by Texas Instruments, DLP is based on a digital micro mirror device (DMD), a chip with millions of hinged, microscopic mirrors attached, each of which corresponds to a single pixel in the projected image. Red, green, and blue light filtered through a color wheel is directed alternately onto the DMD, which switches on and off up to 5,000 times a second. The reflected light is directed through a lens and onto a screen, creating an image. High-end HDTV projectors use a three-chip solution, with separate DMD's for green, red, and blue, and fore go the color wheel.

Dolby Digital

Dolby Digital is a proprietary technology used for creating and reproducing digital surround sound (also called AC-3, or 5:1). The 5:1 format refers to the way digital sound is recorded on six separate tracks: front left, front right, front center, rear left, and rear right, with an extra track reserved for very low bass. This method mimics the three-dimensional quality of sound in real life. Although analog surround sound (called Dolby Pro Logic) also often uses six speakers, the analog format simply splits a traditional stereo signal into front and rear components.

Dolby Digital EX

Dolby Digital EX creates 6 full bandwidth output channels from 5.1­channel sources. This is done using a matrix decoder that derives 3 surround channels from the 2 in the original recording. For the best results, Dolby Digital EX should be used with movie sound tracks recorded with Dolby Digital Surround EX. With this additional channel, you can experience more dynamic and realistic moving sound especially with scenes with “fly­over” and “fly around” effects.

Dolby Digital Surround EX

Dolby Digital Surround EX was co-developed by Dolby and Lucas film THX in time for the release in May 1999 of Star Wars Episode I: The Phantom Menace. It provides an economical and backwards-compatible means for 5.1 soundtracks to carry a sixth, center back surround channel for improved localization of effects. The extra surround channel is matrix encoded onto the discrete Left Surround and Right Surround channels of the 5.1 mix, much like the front center channel on Dolby Surround encoded stereo soundtracks. The result can be played without loss of information on standard 5.1 systems, or played in 6.1 or 7.1 on systems equipped with Surround EX decoding and additional speakers. Dolby Digital Surround EX has since been used for the Star Wars prequels on the DVD versions and also the remastered original Star Wars trilogy. A number of DVDs have Dolby Digital Surround EX audio option.

Dolby Digital Plus

Dolby Digital Plus is an advanced audio technology developed or high definition programming and media including HD broadcasts, HD DVD, and Blu-­ray Disc. Selected as a mandatory audio standard for HD DVD and as an optional audio standard for Blu-­ray Disc, this technology delivers multichannel sound with discrete channel output. Supporting bit rates up to 6.0 Mbps,Dolby Digital Plus can carry up to 7.1 discreet audio channels simultaneously. Supported by HDMI version 1.3 and designed for the optical disc players and AV receivers/amplifiers of the future, Dolby Digital Plus also remains fully compatible with the existing multichannel audio systems that incorporate Dolby Digital.

Dolby Pro Logic

The analog version of surround sound for home video, Dolby Pro Logic splits a regular stereo signal into front and back components, and then usually puts a slight delay on the rear speakers to create an illusion of 3D audio depth. A mono center speaker is usually added to reduce disorientation caused by hearing stereo sound from the sides while watching video in the center.

Dolby Pro Logic II

Dolby Pro Logic II is an improved technique used to decode vast numbers of existing Dolby Surround sources. This new technology enables a discrete 5­channel playback with 2 front left and right channels, 1 center channel, and 2 surround left and right channels instead of only 1 surround channel for conventional Pro Logic technology. There are three modes available: “Music mode” for music sources, “Movie mode” for movie sources and “Game mode” for game sources.

Dolby Pro Logic IIx

Dolby Pro Logic IIx is a new technology enabling discrete multi­channel playback from 2­channel or multi­channel sources. There are three modes available: “Music mode” for music sources,” Movie mode” for movie sources (for 2­channel sources only) and “Game mode” for game sources.

Dolby Surround

Dolby Surround uses a 4­channel analog recording system to reproduce realistic and dynamic sound effects: 2 front left and right channels (stereo), a center channel for dialog (monaural), and a surround channel for special sound effects (monaural). The surround channel reproduces sound within a narrow frequency range. Dolby Surround is widely used with nearly all video tapes and laser discs and in many TV and cable broadcasts as well.

Dolby TrueHD

Dolby TrueHD is an advanced lossless audio technology developed for high definition disc based media including HD DVD and Blu-­ray Disc. Selected as a mandatory audio standard for HD DVD and as an optional audio standard for Blu-­ray Disc, this technology delivers sound that is bit ­for ­bit identical to the studio master, offering a high definition home theater experience. Supporting bit rates up to 18.0 Mbps, Dolby TrueHD can carry up to 8 discrete channels of 24­bit/96 kHz audio simultaneously. supported by HDMI version 1.3 and designed for the optical disc players and AV receivers/amplifiers of the future, Dolby TrueHD also remains fully compatible with the existing multi-channel audio systems and retains the metadata capability of Dolby Digital, allowing dialog normalization and dynamic range control.

Downconvert

In DTV, the conversion from a higher-resolution input signal number to a lower one. For example, some DTV receivers can be set to downconvert an HDTV 1080i signal to a standard 480i signal that any TV can display.

Dropout

Missing information from a broadcast or recorded media and typically show up as white specks in an analog environment. Dropout is more pronounced with interframe compression techniques such as MPEG because the error displays until the next complete frame is drawn, otherwise known as an I-frame. This can take up to ½ a second.

DSD

Direct Stream Digital (DSD) technology stores audio signals on digital storage media, such as Super Audio CDs. Using DSD, signals are stored as single bit values at a high ­frequency sampling rate of 2.8224 MHz, while noise shaping and over sampling are used to reduce distortion, a common occurrence with very high quantization of audio signals. Due to the high sampling rate, better audio quality can be achieved than that offered by the PCM format used for normal audio CDs.

DSP (Digital Signal Processing)

The process used to alter (usually in real time) an audio or video signal in such a way that it sounds or looks different from the original. Examples of signal processing include: boosting bass, simulating a 3D environment, reverb, chorus, and so on.

DTCP

Digital Transmission Copy Protection, A HDTV copy-protection scheme more commonly called 5C.

DTLA

Digital Transmission Licensing Administrator, The licensing organization for the 5C DTCP HDTV copy-protection technology.

DTS 96/24

DTS 96/24 offers an unprecedented level of audio quality for multi­channel sound on DVD video, and is fully backward compatible with all DTS decoders. “96” refers to a 96 kHz sampling rate compared to the typical 48 kHz sampling rate. “24” refers to 24­bit word length. DTS 96/24 offers sound quality transparent to the original 96/24 master, and 96/24 5.1­channel sound with full ­quality full ­motion video for music programs and motion picture soundtracks on DVD video.

DTS Digital Surround

DTS digital surround was developed to replace the analog soundtracks of movies with a 6.1 ­channel digital sound track, and is now rapidly gaining popularity in movie theaters around the world. DTS, Inc. has developed a home theater system so that you can enjoy the depth of sound and natural spatial representation of DTS digital surround in your home. This system produces practically distortion ­free 6.1­channel sound (technically, front left and right, center, surround left and right, and LFE 0.1 (subwoofer) channels for a total of 5.1 channels).

DTS Express

DTS Express is an advanced audio technology for the optional feature on Blu­ray Disc or HD DVD, which offers high ­quality, low bit rate audio optimized for network streaming, and Internet applications. DTS Express is used for the Secondary Audio feature of Blu-­ray Disc or the Sub Audio feature of HD DVD. These features deliver audio commentaries (for example, the additional commentaries made by the director of a film) on demand by the users via the Internet, etc. DTS Express signals are mixed down with the main audio stream on the player component, and the component sends the mixed audio stream to the AV receivers/amplifiers via digital coaxial, digital optical or analog connections.

DTS-­HD High Resolution Audio

DTS-­HD High Resolution Audio is an high resolution audio technology developed for high ­definition disc ­based media including HD DVD and Blu-­ray Disc. Selected as an optional audio standard for both HD DVD and Blu­ray Disc, this technology delivers sound that is virtually indistinguishable from the original, offering a high ­definition home theater experience. Supporting bitrates up to 3.0 Mbps for HD DVD and 6.0 Mbps for Blu-­ray Disc, DTS-­HD High Resolution Audio can carry up to 7.1 discrete channels of 24­bit/96 kHz audio simultaneously. Supported by HDMI version 1.3 and designed for the optical disc players and AV receivers/amplifiers of the future, DTS­HD High Resolution Audio also remains fully compatible with the existing multichannel audio systems that incorporate DTS Digital Surround.

DTS-­HD Master Audio

DTS-­HD Master Audio is an advanced lossless audio technology developed for high ­definition disc ­based media including HD DVD and Blu-­ray Disc. Selected as a mandatory audio standard for both HD DVD and Blu-­ray Disc, this technology delivers sound that is bit ­for ­bit identical to the studio master, offering a high ­definition home theater experience. Supporting bitrates up to 18.0 Mbps for HD DVD and up to 24.5 Mbps for Blu-­ray Disc, DTS-­HD Master Audio can carry up to 7.1 discrete channels of 24­bit/96 kHz audio simultaneously. Supported by HDMI version 1.3 and designed for the optical disc players and AV receivers/amplifiers of the future, DTS-­HD Master Audio also remains fully compatible with the existing multichannel audio systems that incorporate DTS Digital Surround.

DVI

Digital Visual Interface, A digital interface specification created by an industry consortium, the Digital Display Working Group. This universal standard for connecting flat-panel monitors is also used for data projectors, plasma displays, and digital TVs. Using a DVI connector and port, a digital signal sent to an analog device is converted into an analog signal (if the device is digital, such as a flat-panel monitor, no conversion is necessary). There are three different DVI configurations: DVI-A for analog signals, DVI-D for digital signals, and DVI-I (integrated) for both analog and digital signals.

DVR

Digital video recorder, A television recorder such as Replay and TiVo that uses a hard drive, an EPG, and internal processing to drastically simplify programmed recording and playback of recorded programs. A DVR vastly increases recording time compared to VCRs or DVD-recording decks; often enables smart programming, in which the device records an entire series or programming defined by keywords, genre, or personnel; and offers pause control over "live" broadcasts. Also called personal video recorder (PVR) or hard disk video recorder.

E

Edge Enhancement

Generic term for artificial edges created around onscreen objects. With already-sharp, high-resolution sources such as DVD and HDTV, it actually obscures detail and increases noise. Scan-velocity modulation circuits, a TV's sharpness control, or the source itself (such as a DVD) are some possible sources of edge enhancement.

EDTV

Enhanced Definition Television, Also used to describe plasma and other fixed-pixel displays that have 852x480 resolution. They can show an HDTV image but don't provide as much detail as higher-resolution displays.

Electron Gun

A color CRT contains three electron guns that shoot electron beams, causing red (R), green (G), or blue (B) phosphors on the inside front of the screen to light up.

EPG

Electronic program guide. An on-screen display of channels and program data.

F

False Contouring

An artifact common to fixed-pixel displays that produces splotchy, distinct sections in what should be gradual gradations of color or shadows. Also referred to as solarization and posterization.

Fiber-Optic Cable

Fiber-optic cables consist of thin filaments of glass (or other transparent materials) that can carry beams of light. A laser transmitter encodes frequency signals into pulses of light and sends them down the optical fiber to a receiver, which translates the light signals back into frequencies. Less susceptible to noise and interference than other kinds of cables, optical fibers can transmit data greater distances without amplification. But because the glass filaments are fragile, optical fiber must be run underground rather than overhead on telephone poles.

Fixed-Pixel Display

Digital televisions that use discrete pixels to create a picture image, such as plasma, LCD, DLP, LCoS, or any non-CRT display device. In the case of DLP, for instance, each pixel is represented by one of the hundreds of thousands of tiny mirrors mounted on a DLP chip.

Flat-Panel Display

This term usually refers to the LCDs used for notebook computers and desktop displays, but it could also refer to other technologies, such as plasma, that produce flat-shaped screens as opposed to the bulkier CRT technology.

Flat-Panel TV

Video display typically using gas plasma or LCD technology and that measures only a few inches thick.

FPS

Frames per second. The number of individual still pictures that pass by every second to create a moving image. Film runs at 24fps, while video, including DVD, runs at 30fps. To compensate for the difference, 2:3 pull-down detection is used.

Frequency

Take a look at a representation of an analog signal, and you'll see a series of waves. We measure the frequency of these waves by determining how many of them pass a specific point in a given amount of time. This frequency is often measured in cycles per second, or hertz.

Front Projection

Type of TV system in which the picture is projected onto a reflective screen or even a wall. The larger the picture, the more visible the pixels or scan lines and the darker the image. CRT systems use three tubes (red, blue, and green), whereas LCD and DLP uses a single projection lens.