User guide

Understanding DVDs

DVD Di s c st a n D a r D s

If you’ve ever tried to purchase DVDs for the purpose of burning your projects on them, you’ll have

probably noticed the many different formats of DVD disc that are available. While most DVD burners are

capable of burning to many if not all of the formats available, some formats operate better in DVD players than

others. Generally the best DVD discs for burning are DVD-R, as they are capatable with the largest range of

DVD burners and players.

DVD D

i s c ca p a c i t y

An important aspect to understand about DVDs, especially when it comes to authoring your own DVD

project, is how they store and playback information. DVDs, unlike tapes, do not play back information in the

order of which it was recorded, and while they do have a limit to the amount of data that they can hold, that

limit is not measured in minutes or hours, but rather in bytes. A topic of much frustration and confusion when

creating DVDs is why a disc that is advertised to hold 4.7GB can not actually store that much information. This

isbecausegigabytesonadiscaremeasuredusingthe“1000bytesequalsakilobyte”system,whilegigabytes

onacomputeraremeasuredas“1024bytesequalsakilobyte.”So,whenplanningyourproject,keepinmind

thatatypical“4.7GB”DVDcanonlystoreabout4.38GBofcomputerdata.

i D e o De f i n i t i o n

 OneofthemostcommonlymisinterpretedfactsaboutDVDsisthatallDVDcontentishigh-denition.

WhileDVDvideoismarkedlyimprovedoverVHS,itisstillconsideredstandarddenition.Truehigh-de-

nitionfootagecontainsagreateramountofpixelsthanstandarddenitionandalsorequiresadifferenttypeof

discinordertobeplayedbackinmostDVDplayers.Anothercommonmisconceptionisthat16:9(widescreen)

video is in some way a superior quality to 4:3 (standard box) video. This is also inaccurate. Both contain the

same amount of information (pixels), only the aspect ratio is different.

as p e c t r a t i o & co r r e c t i o n

Aspect ratio is the ratio of the width of the visible area of the video frame to the height of the visible

area.Themostbasicaspectratiosare4:3and16:9.DVDshavevariouswaysofdealingwiththedifferent

aspectratios.IfyouarecreatingaDVDwithall16:9footage,you’llwanttocreatea16:9DVD.Thisisneif

your target audience will be viewing the DVD on a widescreen television, but what if they dont? In this case,

we must decide how we want them to view the footage on the DVD. There are three options:

 Therstoptionistosimplyinsert16:9footageintoa4:3trackandgivetheviewertheoptiontoplayit

back that way. However, this stretches the picture vertically and produces an awkward result. The next option

istodisplaythevideowithinaletterbox,whereblackbarsllthetopandbottomportionsofthescreenandthe

aspectratioisunchanged.Thenaloptionistodisplaythevideoin“pan-scan”mode.Inthismode,thevideo

isenlargeduntilitllsthescreen,meaningthesidesofthevideoarecropped.Advanceduserscanevendene

what area of the frame should be visible while in pan-scan mode. The choice between pan-scan and

letterbox is primarily stylistic. Both options will be covered later in this guide.