DVD Players Glossary

3-2 pulldown processing

A process which improves the look of film-based video when it is converted to progressive-scan. The frame rate for film is 24 frames per second (24 fps), and that's the way movies are stored on DVD. The frame rate for broadcast video in the U.S. is 30 frames per second (or more precisely, 60 fields per second).

So, one of the primary tasks of the MPEG decoder inside every DVD player is to take the 24 fps data stored on the DVD and convert it to 60-fields-per-second video for TV viewing. Since 24 doesn't divide evenly into 60, a process called "3-2 pulldown" is employed, where 3 video fields are created from the first film frame, then 2 fields from the next frame, then 3, then 2, 3-2-3-2-3-2, etc. The result is 60-fields-per-second interlaced-scan video, and that's the end of the story for non-progressive-scan DVD players.

Progressive-scan DVD players add an important additional step to create a better-looking picture — they generate a progressive-scan video signal through a process called de-interlacing (sometimes called "line-doubling"). The de-interlacer's first task is to look at the interlaced video signal as it leaves the MPEG decoder and determine whether its original source was 24-frame-per-second film or 30-frame-per-second video. The original frame rate determines the type of processing necessary to create an optimized progressive-scan signal.

Advanced de-interlacers detect 3-2 pulldown on film-based sources and apply 3-2 pulldown processing to create a 60-frame-per-second progressive-scan signal that maintains the original frame integrity, with no mixing of non-matching fields. This processing eliminates jagged edges on still objects and moving angled lines, producing video with the naturally smooth look of film.

Other names for 3-2 pulldown processing include "3-2 pulldown detection," "3-2 pulldown compensation," and "reverse 3-2 pulldown."

4:3 see aspect ratio

Anamorphic

A type of widescreen display format commonly found on DVD movies. It is optimized for playback on a TV with 16:9 aspect ratio (or TVs with a "vertical squeeze" viewing mode like Sony's 16:9 Enhanced). On a standard TV, anamorphic material looks horizontally squeezed. Anamorphic DVDs are often labeled on their cases "enhanced for 16x9 televisions," "enhanced for widescreen televisions," "16x9 anamorphic," or "anamorphic widescreen."

An anamorphic widescreen DVD has significantly higher resolution than a letterboxed widescreen DVD. For example, for a film shot in the commonly-used 1.85:1 aspect ratio, a letterboxed DVD presentation uses only 345 vertical scan lines (the remaining scan lines are taken up by the horizontal black bars above and below the image). That same film in anamorphic widescreen will use anywhere from 460 to the full 480 scan lines. See aspect ratio for more information.

Aspect ratio

The shape of an image or display screen expressed as a width-to-height ratio. The NTSC television standard is the familiar squarish 4:3 (1.33:1), while anamorphic DVDs and high-definition TV broadcasts are in the wider 16:9 (1.78:1) shape. Most movies are made for the wide screen of a theater, and are originally displayed at the wider ratios of 1.85:1 or 2.35:1.

DVD's huge data storage capacity makes it possible to include multiple versions of a movie on a single disc. It's not unusual for a DVD disc to feature a Standard (4:3) version on one side and a Widescreen version on the other.

For TVs with standard 4:3 screens, movies (whether on disc or tape) must be re-formatted to either "letterbox" or "pan-and-scan." If you usually rent or buy VHS movies, you're probably used to pan-and-scan versions, which are preceded by this message: "This film has been modified from its original version. It has been formatted to fit your screen."

Pan-and-scan provides an image with full height, but shows a central "window" that is only 75% of the original widescreen width. What this window shows is determined by the preferences of the person(s) performing the film-to-disc transfer.

Widescreen DVDs will be either letterboxed or anamorphic. For letterboxed DVDs, the player uses a "letterbox filter" that adds horizontal black bars to the top and bottom of the picture. What you see is a short, rectangular image that maintains the movie's full original width.

Anamorphic DVDs deliver a higher-resolution widescreen presentation. For an explanation of anamorphic widescreen, see anamorphic.

Bitstream

A signal that contains digital data in its undecoded state. An example is the signal that's fed through a DVD player's digital output(s), which carries Dolby Digital, DTS, or PCM signals.

Blu-ray Disc™

Similar to HD DVD, Blu-ray Disc is a new format designed specifically for HDTVs. It offers a much greater storage capacity than DVD for better picture and sound. See our article on HD DVD and Blu-ray for more information.

Cable box control

Some DVD recorders or digital video recorders (DVRs) can control major brands of cable boxes. This is useful for making unattended timer recordings, because the cable box will automatically be changed to the right station at the right time.

Chrominance

The color information portion of a video signal that describes an image's color shade and vividness.

Coaxial digital output

Component video

A video signal in which the chrominance (color) and luminance (brightness) portions of the signal are processed separately. Component video signals provide greater color accuracy than S-video or composite signals.

Why is component video superior to S-video? Where S-video separates the luminance and chrominance portions of the signal, component video goes a step further and splits the chrominance portion into two components. The benefits — improved color accuracy and less color bleeding — are especially noticeable on larger-screen TVs.

Composite video

A video signal in which the brightness and color portions of the signal are combined. Examples of composite video include standard VHS, laserdisc, and regular broadcast TV. A DVD player's standard RCA-type video jack provides a composite video signal.

Copy protection

A system for preventing the unauthorized reproduction of copyrighted media like movies or music. The DVD format includes both digital and analog forms of copy protection. You will probably not be able to copy DVDs with your VCR. (In fact, because the copy protection system is triggered by a circuit found in most VCRs, simply playing a DVD and running the signal through your VCR will often result in a distorted picture. You should bypass the VCR altogether and connect your DVD player directly to your TV.)

De-interlacing

The process of converting an interlaced-scan video signal (where each frame is split into two sequential fields) to a progressive-scan signal (where each frame remains whole). De-interlacers are found in progressive-scan DVD players and digital TVs. More advanced de-interlacers include a feature called 3-2 pulldown processing. With TVs, de-interlacing is sometimes referred to as "line-doubling."

Digital output

All DVD players include at least one digital audio output for sending the Dolby Digital or DTS bitstream to a compatible decoder (which is usually built into an A/V receiver). Digital data transfer offers extremely wide bandwidth, immunity to RF interference, and an easy one-cable connection.

The two most common types of digital output are coaxial and optical. Although a coaxial digital jack looks like a standard RCA-type audio jack, both coaxial and optical jacks require special cables to connect to the digital input of your Dolby Digital/DTS-equipped receiver. Note: Most DVD players do not include digital cables.

Digital-to-analog converter (DAC)

An electronic circuit that converts a series of digital "words" into a continuous analog signal. DVD players include separate DACs for audio and video.

Disc capacity

The number of discs a DVD player or changer can hold.

DivX®

A technology that compresses a video file to a fraction of its original size for easy storage and sharing, just as MP3 does for music files. Some DVD players can play DivX files recorded to CDs or DVDs.

Dolby® Digital

A discrete multichannel digital audio standard offering enhanced sonic realism. Dolby Digital is normally associated with 5.1-channel surround sound. Though this channel configuration is common, it is only one of several possible variations — a "Dolby Digital" soundtrack can mean anything from 1 to 5.1 channels.

If you're specifically looking for titles with a 5.1 soundtrack, you should carefully read each DVD disc's packaging. Relatively few older movies with stereo or mono soundtracks will be remastered with 5.1-channel surround for DVD.

Dolby Digital 5.1 soundtracks will in most cases provide the most satisfying sound quality for a home theater system. It is referred to as a 5.1-channel system because it offers five full-bandwidth channels (including true stereo surrounds), plus a "low frequency effects" subwoofer channel.

Unless your DVD player has its own built-in Dolby Digital decoder, you'll need to connect your player to a receiver or processor that can take the digital bitstream from the disc and convert it into 6 channels of audio. Dolby Digital uses a data compression technique called "perceptual coding" to reduce the original amount of audio data by a factor of about 10:1.

Downmixed audio

If you don't have a Dolby Digital system, you can still enjoy excellent Pro Logic® or stereo sound. All DVD players have the ability to take a 5.1-channel Dolby Digital soundtrack and "downmix" it to two channels, which can then be sent to a stereo TV, a stereo receiver, or to an A/V receiver with Dolby Pro Logic decoding.

DTS® (Digital Theater Systems)

DTS is a well-established multichannel audio format in movie theaters, but not as common in home theater applications. Like Dolby Digital, DTS is primarily a 5.1-channel format. The compression scheme used in DTS "throws away" significantly less audio data than Dolby Digital, so theoretically it should sound better, but so far, side-by-side comparisons have been inconclusive.

Nearly all new DVD players are DTS-compatible; some players and nearly all new A/V receivers include DTS decoding. Still, the number and availability of DVD titles with DTS soundtracks remains somewhat limited.

DualDisc

A DualDisc is a new two-sided disc that combines audio on one side with a DVD on the other side. The audio side carries stereo music, while the DVD side usually offers a multichannel version in Dolby Digital, DTS, or DVD-Audio in addition to video footage. Extras can include lyrics, documentaries, interviews, photo galleries, and more.

A DualDisc will probably play in most CD or DVD players. However, since DualDisc is slightly thicker than regular CDs, it may get stuck in some slot-loading players, or the DVD side may get scratched. A number of consumer electronics manufacturers have posted advisories regarding these issues, including Denon, JVC, Onkyo, Sony, and Toshiba.

Keep in mind, if the DualDisc has DVD-Audio content on the DVD side, you'll need a DVD-Audio-capable player in order to listen to that portion of the disc. Even if you don't have a DVD-Audio player, most discs will have a multichannel Dolby Digital mix in addition to DVD-Audio, so that they can still be played in a regular DVD player.

DVD-Audio (DVD-A)

A music-oriented DVD format that can carry up to 6 channels of 96kHz/24-bit audio (music for 5.1-channel home theater systems), or 2 channels of ultra high-resolution 192kHz/24-bit audio. Most DVD-Audio discs also carry lower-resolution Dolby Digital or stereo soundtracks for playback on DVD players that lack DVD-Audio decoders. A DVD-Audio disc may also contain liner notes, lyrics, menus, and still pictures that display on your TV. DVD-Audio uses MLP compression.

DVD-R/RW, DVD-RAM, DVD+R/RW

DVI (Digital Visual Interface)

A multi-pin computer-style output included on a few DVD players. DVI provides a an "upconverted" or upgraded DVD video signal to HD-compatible TVs with a compatible connector. This digital video signal is encrypted with High-bandwidth Digital Content Protection (HDCP) to prevent recording.

DVR (Digital Video Recorder)

Also known as a personal video recorder (PVR) or hard disk video recorder. DVRs store recordings on a large hard drive, and most let you pause and replay live television. When used with an electronic program guide service, you can find and record shows automatically.

Electronic program guide (EPG)

Provides an on-screen listing of available channels and program data for an extended time period, usually 1-2 weeks. Examples of program guides include subscription services like TiVo® and free guides like TV Guide On Screen®.

Field

In interlaced-scan video, each complete frame is split into 2 sequential fields, each of which contains half the scanning lines of the frame. One field contains the odd scanning lines, and the other field the even lines.

Frame

A complete, individual picture in a movie film. In a video signal, a frame contains all of the picture's scanning lines.

Frame rate

The rate at which frames are displayed. The frame rate for movies is 24 frames per second (24 fps). In regular NTSC video, the frame rate is 30 fps.

Hard disk video recorder

See DVR.

Hard drive size

The amount of recording space on a digital video recorder's (DVR) hard drive, generally given in GB (gigabytes). A rough rule of thumb is that 1GB = 1 hour of programming, with the approximate quality of a VHS recording. You can fit more video on the hard drive by lowering the recording quality. If you use a higher recording quality, you'll be able to fit less video.

HDCD® (High Definition Compatible Digital)

An enhanced method of audio recording for CDs developed by Pacific Microsonics. HDCD claims to be able to capture 20-bit resolution. Although the HDCD-enhanced information can only be heard using a DVD or CD player with built-in HDCD decoding, HDCD discs are still playable on regular DVD and CD players.

HDCP (High-Bandwidth Digital Content Protection)

HDCP encryption is used with high-resolution signals over DVI and HDMI connections to prevent unauthorized duplication of copyrighted material.

HD DVD

HD DVD is a new high-definition disc format designed from the ground up to maximize the viewing experience available from today's HDTVs. HD DVD discs and players offer several advantages over the regular DVD format, including improved picture and sound quality.

HDMI (High-Definition Multimedia Interface)

Similar to DVI (but using much smaller connectors), the multi-pin HDMI interface transfers uncompressed digital video with HDCP copy protection and multichannel audio. Using an adapter, HDMI is backward-compatible with most current DVI connections. HDMI connectors are found on a few upconverting DVD players, A/V receivers, and TVs. .

IEEE 1394

Also known as "FireWire" or i.LINK®, this all-in-one, high-speed digital interface is becoming an industry standard for the transmission of digital audio/video data. It permits data transfer between compatible digital components, such as a camcorder and DVD recorder, with virtually zero loss in video or audio quality.

Interlaced scan

DVDs use 480 lines to make up a frame (picture). The frame is made up of two fields: The first field has 240 odd lines (1,3,5...) and the second field has 240 even lines (2,4,6...). The odd lines are scanned (drawn on the screen) in 1/60th of a second, and the even lines follow in the next 1/60th of a second. This presents an entire frame/picture of 525 lines in 1/30th of a second.

IR blaster

A device that enables a DVD recorder or DVR to control your cable box or satellite receiver by sending signals that mimic those of a remote control. An IR blaster, or flasher, looks like a regular cable with two distinctly different ends. One end plugs into the back of a compatible DVD recorder or DVR. The other end is the IR emitter. It sits in front of the cable box/satellite receiver's IR sensor, which is located on the front-panel. IR blasters make for easier unattended timer recordings, since the DVD recorder/DVR can tune the set-top box to the right channel at the right time.

JPEG CD

JPEG is a way to encode full-color digital images so that they're smaller and easier to store and transfer. Its compression takes advantage of the human eye's inability to see minute color changes by removing portions of data from the original picture file. Many DVD players and recorders can read JPEG files burned to a CD, and display them on a TV.

Letterboxing

The scaling of a widescreen image to fit a standard 4:3 aspect ratio TV screen by shrinking the image so that the width fits exactly. The horizontal black bars that appear above and below the image are actually recorded with the picture, so some of the picture's vertical resolution is lost when you view it. Letterboxing is much more common on DVD movies than VHS videos.

Luminance

The brightness component of a color video signal. Determines the level of picture detail.

MLP (Meridian Lossless Packing)

A lossless compression technique (used on DVD-Audio discs) that removes redundancy from PCM audio signals. MLP achieves a compression ratio of about 2:1 while allowing the signal to be perfectly re-created by an MLP decoder.

MPEG2

The digital video signal compression standard used for DVD. This adaptive, variable bit-rate process is able to allocate more bits for complex scenes involving a lot of motion, while minimizing the bits in static scenes. The average data rate for DVD is 3.5 Mbps (million bits/second).

MPEG stands for Moving Picture Experts Group.

Multi-language capability

DVD is designed to make it easier for movies to be distributed in multiple languages. A single DVD disc can contain soundtracks in up to 8 different languages.

In addition to multilingual dialogue, a DVD also has space for subtitles in up to 32 languages. Note: the number of soundtracks and subtitles will vary from disc to disc depending on the length of the movie and whether or not other special playback features are included.

Optical digital output

See digital output.

Pan-and-scan

A technique for making a widescreen movie fit a standard TV's 4:3 aspect ratio by showing only selected portions of the original image. This is the standard practice on VHS videos ("formatted to fit your screen"), but is less common on DVDs.

Parental lockout

A small percentage of DVD movies include variable ratings capability. According to the movie rating level you select, the player will skip over certain scenes, playing the version that you choose from those available on the disc.

PCM (Pulse Code Modulation)

The digital audio signal format used for Compact Discs. Digital outputs on DVD players are often labeled "Bitstream/PCM" because they can send the Dolby Digital or DTS bitstream from a DVD, or the PCM bitstream from a CD.

Perceptual coding

A type of data compression used in recent digital audio and video formats. Audio examples include Dolby Digital and MP3. The best example of video compression is MPEG2, which is used for DVD and most digital satellite TV. These forms of data compression are based on sophisticated research into how we perceive sounds and images.

Perceptual coding omits "imperceptible" sound and picture data which is redundant or which is judged to be masked by similar information. In the case of DVD, by "throwing away" a lot of redundant and unnecessary information, it's possible to fit multiple versions of a movie on a single 5-inch disc.

Progressive scan

A feature on all nearly current DVD players, as well as some older models. Instead of splitting each video frame into two sequential fields like interlaced scan, progressive scan displays the entire frame in a single sweep. So, where an interlaced signal from a DVD player (480i) displays 30 frames (60 fields) per second, a progressive-scan signal (480p) displays 60 full frames per second. Progressive-scan picture quality is more filmlike, with more fine detail and less flicker. Watching progressive-scan signals requires a compatible digital TV (EDTV, HDTV-ready, or full HDTV). To ensure that progressive-scan players are still compatible with analog TVs, they have selectable outputs for interlaced or progressive signals. Also see interlaced scan.

Interlaced scan splits the image into two fields, alternating between the even (2,4,6…) and odd (1,3,5…) scan lines every 1/60th second, and effectively displaying a full frame every 1/30th second. Progressive scan, on the other hand, displays all the lines at once (1,2,3,4…), displaying a full frame every 1/60th second.

Recordable DVD

The popularity of DVD technology led to machines that not only play DVDs, but record on them, too. Recordable DVD combines high-quality audio/video recording with tape-free convenience.

There are three competing recordable-DVD camps, backed by various electronics and computer companies. These three camps are DVD-R/RW, DVD-RAM, and DVD+R/RW. Some of these formats use discs that can only be recorded once; others use discs that can be erased and re-recorded.

• Write-once: DVD-R, DVD+R
• Rewriteable: DVD-RW, DVD+RW, DVD-RAM

 

For more details on recordable DVD, see our DVD Recorders article.

Region codes

The movie industry insisted that the DVD standard include codes which would limit playback to a specified geographical region. This was done because theater and home video releases of movies do not occur simultaneously worldwide. For example, a movie may be released on video in the U.S. just as it's first appearing in theaters in Europe.

DVD players have a built-in region code lockout feature, while the DVD discs may or may not contain a code (region codes are optional on DVD software). A player will be unable to play a disc that has a different region code. Discs may contain codes for more than one region, or may not have any code, which allows them to be played on any player in any country. The region code for USA/Canada is "1". Note: Many recent DVDs will not play in modified "code-free" DVD players.

Scaler

Circuitry that converts a video signal to a resolution other than its original format. A few DVD players — typically those that include a DVI or HDMI input — are able to "upconvert" the DVD signal to a higher resolution, such as 720p or 1080i for displaying on an HD-compatible TV. Also see video upconversion.

Signal-to-Noise ratio (video)

This ratio is a measure of the content portion of the video signal in relation to the noise in the signal. As with audio, video signal-to-noise is measured in decibels (dB). The way the decibel scale works, if component A has a signal-to-noise (S/N) ratio of 20 dB and component B has a S/N ratio of 30 dB, component B will have ten times less noise in the signal than component A.

Basically, a S/N ratio tells you how "clean" a video signal is. Because of the way they process signals, digital video formats like DVD and digital satellite TV are extremely clean. A standard VHS VCR may have a S/N spec in the low 40s; a laserdisc player, the low 50s. DVD is rated to deliver a video S/N ratio of 65 dB.

Super Audio CD (SACD)

A high-resolution digital audio format developed by Sony and Philips. Instead of using PCM audio encoding like standard CDs, SACDs use Direct Stream Digital™ (DSD) encoding. DSD is a 1-bit technology that samples music at the rate of 2.82 million times per second, compared to standard CD's rate of 44,100 times per second. SACDs sound more detailed than standard CDs, with greater dynamic range. All SACDs contain a high-resolution stereo mix; many also contain a high-resolution surround mix, with up to 6 independent channels.

S-video

This video connection carries the chrominance (color) and luminance (brightness) portions of the video signal in separate streams, for improved color accuracy and reduced distortion. S-video provides a sharper picture than composite video, but is not as good as component video.

TiVo

A subscription service that popularized DVRs. Includes a 14-day program guide, WishList™ (search and record), Season Pass™ (record whole seasons of a program), and more.

TiVo Series2™

The second generation of TiVo boxes, first available in 2002. Series2 boxes support free Home Media networking features. Also, Series2 boxes that don't have a built-in DVD recorder support TiVoToGo™, which lets you save your TV recordings to your desktop or laptop PC.

TV Guide On Screen interactive program guide

A free service included with the purchase of some digital video recorders (DVRs), DVD recorders, and TVs. Includes an 8-day program guide, handy searching functions, and smart recording features.

Video upconversion

A feature found on more and more DVD players, and even some recorders. "Upconversion" is the term used to describe the conversion of a lower image resolution to an apparently higher one. In order to achieve that higher resolution, the player fills in additional image data by assessing existing pixels and intelligently predicting what the surrounding pixels should look like.

Upconversion is a great feature for owners of High-Definition-capable digital TVs who want to watch their DVDs at a higher resolution that more closely matches the capabilities of their TV. Upconverted video is typically only available via digital connections like DVI and HDMI. Though the quality of upconverted signals can vary from model to model, upconversion generally makes for a better picture.

WMA CD

WMA stands for Windows® Media Audio. Like MP3, WMA compresses audio files for easier storage. Some DVD players and recorders can read WMA files burned to a CD.