Confused by the -'s and +'s of DVD reading and writing? Find out what you need to know here!

by Drew Dunn
2006/05/23

Four or five years ago, I was an early adopter of DVD technology for my home entertainment system. The idea of a movie with a five channel digital soundtrack on a disk the size of a CD was very appealing to me, particularly when the video and audio quality was much superior to a VHS tape’s.

Of course, four or five years ago, a DVD player with all of the capabilities of today’s sub-$100 models ran upwards of $450 or $500, so being on the leading edge of home entertainment technology (like most technology) had its drawbacks. For what it’s worth, I did the same thing when compact discs came out in the early 80’s.

Like compact discs, DVD (Digital Video Disc or Digital Versatile Disc, depending upon who you talk to) have made the logical jump from your home entertainment center to your computer. After all, a DVD player connected to the TV is really just a special purpose computer and bits are bits. So, if you shop around a little, you can add a DVD drive to your computer for somewhere around $50. Not a bad deal, because, like its home entertainment brethren, it also plays CDs, giving you two formats to choose from.

And, like computer CD drives, you can install a recordable DVD drive. But unlike the CD burners, a DVD recorder comes in different formats. Alas, they are not all compatible with each other. Let’s sort out what is what and which format is best for you.

If you remember the battle between Beta and VHS, this should be familiar ground. There are two competing format camps: DVD+R/DVD+RW and DVD-R/DVD-RW/DVD-RAM.

DVD+R and DVD+RW are formats from Philips, Sony, Dell, Yamaha, Hewlett Packard and some other smaller companies. DVD+R, like CD-R, allows the disc to be burned once. DVD+RW is like CD-RW. Burn, erase, burn, erase…you get the picture. You can play both of these discs on the DVD decks in your home entertainment system.

DVD-R, DVD-RW and DVD-RAM (also called DVD-Multi) are supported by Toshiba, Apple, Panasonic, NEC, Samsung and a few other companies. DVD-R is also like CD-R. The DVD-R standard comes in two different types: DVD-RG is the typical format that you would use in a computer, while DVD-RA is designed for mastering DVD video or audio and is used as the master copy for a commercial manufacturing process. Generally, DVD-RA is not found outside of professional mastering facilities.

DVD-RW allows for repeated cycles of writing and erasing, like CD-RW. Both DVD-R and DVD-RW discs can be read in your home DVD player.

DVD-RAM discs are rewritable, but are only supported by DVD-RAM drives. They work only in a DVD-RAM system, typically not in a DVD player. They do have the ability to be written to in the same way that you would a hard drive. They don’t require special software – you just drag and drop like any other drive.

So, you ask, what is the REAL difference, besides a little bit of alphabet soup? Good question!

For you and me (the average consumer), there’s not a big difference, other than one format group cannot write to the other format group’s media. Both format groups hold about 4.7GB of data per side of the disc, both use organic dyes for the non-erasable and phase-change material for the erasable discs. The prices are about the same for the media and drives (well, DVD-RAM disks may be a little more expensive).

DVD-RW and DVD-R are the only formats supported by the DVD Forum. But since the DVD Forum doesn’t set standards, that may not be much of an issue. Also, it turns out that most of the companies who support DVD-RW and DVD-R are members of the DVD-Forum, so they are aware of what is necessary to give their equipment the ability to read the other formats.

A ray of sunshine is emerging from the confusing field of different formats. Sony has released a multi-format drive that supports DVD-R/RW, DVD+R/RW and CD-R/RW, the DRU500A. Other manufacturers are following, so perhaps the dreaded format battle may never come to pass after all.

And what was my choice for a DVD burner? I don’t have one...just a lowly CD burner. Maybe someday I’ll have enough data around to need one!