DVD - What on earth is that?

DVDs getting more and more popular and millions of DVDs have been sold this year. Why do poeple prefer DVDs, what happened to VHS? Below is what a DVD is.





Akmal Khan Sapay

.2003.07.27.

What is a DVD?

DVD stands for or rightly said used to stand for Digital Video Disk. But it did not take long before it was discovered that this technology can even be used to save data other than video in MPEG 2 (Moving Pictures Expert Group) format. As a result the name was changed to Digital Versatile Disc. MPEG is a standard format for video compression and then there are developed versions of this format namely MPEG-1, MPEG-2 and MPEG-4.

MPEG-1 is used in creation of VCD movies and doesn’t have any impressive video quality. MPEG-2 on the other hand is the format which is used to create SVCD and DVD movies. Giving a very high video quality and sharp picture the MPEG-2 format is far better than MPEG-1. MPEG-4 is used in creation of DIVX movies.

A DVD is as metioned before the absolutely best choice when it comes to video quality. The bitrate used in the MPEG-2 format is between 5 to 25 MB/s and by comparison it should be mentioned that DVD has a screen resolution of 720x576, almost double that of VCD.

The downside is that a DVD can take 4 to 8 times as much space as a VCD and that is the reason the DVD discs are totally different from ordinary CDs. A traditional CD can save data upto 730 MB while DVD can save 4,7 GB of data on a single layer. The future of DVD is quite bright since more and more people are preferring DVDs over VCDs despite the difference in prices.

See the table below to understand the differences between different video compression formats:

NOTE: The comparison table is excerpted from www.vcdhelp.com