Technology > Technical FAQ

Updated March 31, 2012


They [DVD discs] look like Compact Discs. What's the big deal?

DVD discs are the same diameter (120mm) and thickness (1.2mm) as a Compact Disc, but that is where the similarities end. A single DVD disc has the capability to store up to 13 times the data contained on a CD, on one side! If you factor in DVD's capability to utilize both sides of a disc for data storage, you have an information marvel that offers 26 times the power of a Compact Disc!

That enhanced capability is a tremendous enabling device. DVD will revolutionize Multimedia, information retrieval and storage and mobile navigation. DVD will create new high quality audio standards, impact learning and training videos, and bring the Cinema experience to Home Entertainment.

How long will DVD movies play before I have to turn the disc over?

At an average bit rate of 4.5Mbs, a single sided DVD disc has the playback capability of 133 minutes of the highest quality audio and video images. That's nearly 92% of all Hollywood titles ever made!

In fact, a dual layer DVD disc can provide up to 4 hours of the highest quality audio and video on a single side of the disc!

Will DVD movies play on my current CD player?

No, you will require a DVD player that is equipped to read the pits and lands of a DVD disc and decode the MPEG-2 data signal.

What is the digital audio output on the back of my DVD player for?

This connector outputs a digital data stream that may be sent to an outboard D/A converter for 2 channel audio processing. More importantly, it may be connected to an audio receiver equipped with a Dolby AC-3 processor for multi-channel audio decoding.

What are the advantages of Dolby Digital Surround AC-3?

Dolby Digital Surround offers discrete processing of 5 independent channels ( Left, Center, Right, Left Surround, Right Surround, and an additional effects channel that may be routed to a subwoofer) of audio information. Dolby Digital Surround provides the producers of movie soundtracks added flexibility and creativity in the studio that results in more realism, and a "you are there experience." Each of the 5 Audio channels is a full range (20-20khz) signal. The discrete nature of Dolby Digital Surround provides increased clarity (especially critical for dialogue) and spatial realism. With Dolby Digital Surround, audio images may be panned across the front of the room; from front to rear; from rear to front; and even diagonally.

Will DVD discs wear out, like VHS movies?

No. The picture quality of the DVD disc is consistent from the first play to the thousandth play. Plus, DVD discs will not deteriorate over time, are unaffected by magnetic fields (which can literally erase a VHS cassette) and do not require rewinding after viewing.

What is an Aspect Ratio? Why is it important?

Aspect ratio refers to the ratio of width to height of a television set. Traditional television sets have a 4:3 aspect ratio. Widescreen television sets have a 16:9 aspect ratio. Traditional television sets are almost square in appearance; widescreen displays are more rectangular.

The DVD defines the capability to display movies in 3 different ways:

  1. Widescreen, which provides a special "anamorphic video" signal that, when processed by a widescreen television set, fills the entire screen and delivers optimum picture quality.
  2. Pan and Scan, a version that fills the screen of traditional 4:3 television sets with an entire picture, much like watching network movies.
  3. Letterbox mode, which provides horizontal bands at the top and bottom to, in essence, create a widescreen picture in a traditional television set.

Each of the 3 display modes, if provided by the Hollywood producer, may be selected for viewing if the viewing device (player or DVD-ROM playback sub-system) is so equipped.

I do not own a Dolby Digital Surround AC-3 receiver. Can I still enjoy my Home Theater audio system with DVD?

Yes, every DVD player currently on the market has analog ( Left and Right ) audio outputs that you can connect to your Dolby Surround Sound, or Pro-Logic receiver. The analog audio outputs of your DVD player passes through specially encoded Dolby Surround Sound signals.

My television set has Composite and S-Video inputs. What is the best way to connect my DVD player?

DVD is a format that will provide significant picture quality advantages when connected to your television set via the S-Video connectors. Your DVD player must have S-Video output to take advantage of this capability.

Are there any other adjustments I should make to my television to take advantage of S-Video?

Yes. The color detail signal is so rich, you will find that you do not need to turn your sharpness control up when watching DVD. In fact, in many television sets, you will optimize picture quality by turning the sharpness control off!

Just how good is the DVD picture?

Based upon pixel resolution, color resolution, color detail, black level reproduction and a virtual lack of color noise, the DVD picture is nearly 3 times better than conventional VHS.

Is DVD picture quality better than Laserdisc?

Yes. DVD is component video, Laserdisc is composite video. The DVD picture is characterized by more color detail, and color resolution and contains significantly less NTSC picture artifacts than Laserdisc. It is generally accepted that a Laserdisc is capable of producing 400-425 horizontal lines of resolution. A DVD disc produces in the range of 480-500 horizontal lines of resolution. A single sided 4.7" (120mm) dual layer DVD disc can store up to 4 hours of the highest quality audio and video images. A 12" Laserdisc can only store 60 minutes on a single side. And DVD movies will play on your computer equipped with a DVD-ROM and appropriate MEPG decode devices. DVD is the realization of true cross-platform multimedia.

Is it [DVD] better than DSS?

Yes. DVD is mastered as CCIR601 4:2:2 digital component video and utilizes 100% MPEG-2 data reduction. DSS, on the other hand, is 4:1:1 digital component video and features scaleable compression schemes that vary from MPEG-1 to MPEG-2. In fact, the digital component video signal of DVD has the capability to rival the best studio masters.

Do I need a Widescreen TV to play 16:9 movies?

A DVD-player can be connected to any television, but with a Widescreen TV you will get the most viewing enjoyment. With DVD-Video you can gradually build up your own Home Cinema system with widescreen TV and multichannel digital surround sound. DVD-Video supports multiple aspect ratios. Video stored on a DVD in 16:9 format is horizontally squeezed to a 4:3 (standard TV) ratio. On Wide-screen TVs, the squeezed image is enlarged by the TV to an aspect ratio of 16:9.

DVD video players output widescreen video in three different ways:

  1. Letterbox (for 4:3 screens)
  2. Pan & scan (for 4:3 screens)
  3. Anamorphic or unchanged (for wide screens)

In widescreen or letterbox mode, if a movie is wider than 16:9 (and most are), additional thin black bars will be added to the top and bottom at production time or the sides will be cropped. Video stored in 4:3 format is not changed by the player. It will appear normally on a 4:3 screen. Widescreen systems will either stretch it horizontally or add black bars to the sides.



back | Top

Copyright© 2004, the DVD Forum | All Rights Reserved