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DVD Formats

Sure, it would be nice to be on the cutting edge of technology and also have everything running smooth, but by definition the cutting edge isn’t smooth. Nowhere is this more apparent than in the profusion of standards for DVD-video and DVD-ROM. In this tip we will attempt to reduce some of the turmoil in the subject.

Pre-recorded DVDs come in two sizes, 80mm and 120mm (same size as the standard CD). As our first step in simplification we are going to ignore the 80mm size (DVD 1-4) and focus on the 120mm formats most commonly used for DVD-ROM. There are five formats to be concerned with that vary primarily in the number of data layers and whether they can accept data on both sides of the disc.

Then you rent or buy a movie on DVD today it will most likely be DVD-9, although older films and a few newer ones will be found on DVD-5. The other three formats are emerging technologies used in the video industry that may or may not find their way into the retail market.

Just about all DVD players today support both DVD-5 and DVD-9, and will also play CDs. However, if you want to play CD-Rs and DVDs on the same unit, make sure you get a player that is labelled “dual optics” or “twin laser” or something similar (In most cases, the player will state on the box what types of media it will support). That’s because CD-R uses a different frequency of laser, and most DVD players will not read CD-Rs well unless there is a second laser for that purpose. Or you could get a combo drive, designed to read DVDs but also to read and write CD-R or CD-RW.

The standards for recordable DVD are a different story altogether, because there are four versions right now fighting for industry supremacy and of course they are not compatible. If you invest in the wrong one it will soon be out in the garage with your old Betamax recorder and that collection of 8-track tapes.

At the moment DVD-R holds the lead for one-time recordable DVD discs, and the two front-runners in re-writable DVD are DVD-RW and DVD+RW. If we had to place a bet on one or the other it would probably be DVD+RW because it provides the greatest compatibility, for both video and data recordings. A recent test showed DVD-RW to be compatible with just over 70% of the players on the market. Also recently available are DVD-ROM recorders that support DVD+R/RW AND DVD-R/RW formats for maximum compatibility.

Now that prices on DVD recorders have dropped from thousands of dollars to less that $250 for an adequate model, you may be thinking it would be nice to back up some of the expensive DVD movies your kids are playing around the clock. If you look at the tables above, you will notice that none of the recordable DVD formats are double-sided, and the maximum capacity is 4.7GB. A little basic arithmetic will tell you that a DVD-9 movie just isn’t going to fit, but there are some options available.

First, if you copy the movie only and omit the extras, you’ll find that many if not most films will fit nicely on a 4.7GB disc. For longer films, compression is an option if you are willing to sacrifice a certain amount of image quality. And of course you can always split the movie onto two discs, just like the old days at the Main Street movie house. Two reels per feature, with an intermission.

This all assumes that the original disc isn’t copy protected. There are several copy protection schemes out there with the most common being Macrovision, and there are even DVDs copy-protected by country or region. You may have heard that there are ways to bypass copy protection, but according to our lawyers you didn’t hear it from us.

Well, we hope this has helped to clear things up rather than scare you away. No matter how you cut it, DVD is a giant leap from the 700MB / 80 min. limit of CD-RW, and in one form or another DVD is here to stay for a while.

Disclaimer - The Micro 2000 Tech Tip is a free service providing information only. While we use reasonable care to see that this information is correct, we do not guarantee it for accuracy, completeness or fitness for a particular purpose. Micro 2000, Inc. shall not be liable for damages of any kind in connection with the use or misuse of this information.