Optical Formats, DVD+/-....

DVD-ROM 8.5 GB DVD-9: single sided, double layer, 8.5 GB (7.92 GiB)
DVD-R 4.7 GB single sided, single layer, "most experienced DVD users would agree, is that the “-“ media is slightly more compatible than the “+” media"
DVD-RW 4.7 GB single sided, single layer
DVD+R 4.7 GB single sided, single layer
DVD+RW 4.7 GB single sided, single layer
DVD+R DL 8.5 GB single sided, double layer
5.2 GB
Own format, not compatible with any of the above (2.6 GB is single sided disk, 5.2 GB for double sided; must manually turn disk up-side-down to access other side)
HD Format    

For more extensive details on DVD formats, see en.wikipedia.org/wiki/DVD. Or www.webopedia.com.

1/20/06 Demystifying those confusing DVD formats


Hi, I'm going to buy a new DVD player/burner for my computer soon, but I don't know what kind of format to choose. There are burners for DVD-R, DVD+R, DVD-RW, DVD+RW, and even dual-layer ones, and many players that support a combination of the formats. I've also been reading some about DVD-RAM, HD-DVD and Blu-ray--just enough to confuse me more! Can you tell me what the specific difference is between these formats so that I can make the best buying decision for current and future use? Help me, please!

Submitted by: Andy T. of Ogden, Utah



It’s best to tackle several categories of DVD media separately, then understand that they get combined to form a whole bunch of different media.

The first distinction is + media vs. - media. These two classes of DVD media, developed separately by different groups of engineers, are conceptually the same from an end user's perspective, but internally they are made differently, and they work differently. What you need to know is that they are different, and that you cannot automatically assume interchangeability. While virtually all recorders made today can record both types, at one time, a recorder was either + or - and would work only with that type of media, and many of these single-format recorders are still around. So you need to know if your recorder (or any other recorders that you plan to use) are dual format or single format. You can actually tell what the recorder will handle from the logos on the front of the recorder. The groups that created the two formats created unique logos, and one of the licensing requirements is that the respective logo must be present if the recorder handles that format (I’d love to show you the logos, but I don’t know how to include graphics in this response).

On the player side, about 80% of players (and just about 100% of newer players) will play both types, but, again, you may run into players that play only one format or the other. The bad part that there is no way to tell other than by trying a sample of recorded media, and in a few cases players may also be finicky about the brand of media. So, really, to be absolutely sure, you have to actually try the media that you plan to use. However, most modern computer drives to play both, where you usually see issues is with older “set top box” DVD players.

As a comment here, my own experience, and I know that most experienced DVD users would agree, is that the “-“ media is slightly more compatible than the “+” media, which is interesting because during the design phase, and “on paper”, it was supposed to be just the other way around. But the “real world” didn’t read the design specs.

Now that we have the +/- issue resolved, the +/- will be followed by “R” or “RW”. “R” media is “one-time” media; recording is permanent and cannot be erased (you can, however, “add to” a partially recorded “R” DVD, if it was recorded in multi-session by recording software that supports this). On the other hand “RW” media can be erased and reused, becoming “completely blank” media over and over again.

One comment here, however, I’d recommend that you avoid “RW” media for permanent projects. It is not as stable as “R” media, and many, many people have found that a recorded “RW” disc “faded” over time and that the data (their recording) was lost. RW media is also both slower and more expensive (a LOT more expensive) the “R” media, so I think that the best advice is probably just to avoid it.

So that takes care of 4 media types: DVD-R, DVD+R, DVD-RW, DVD+RW.

Now we can add “dual layer”, which you will see as a “DL” suffix. This media has almost twice the capacity of single layer media (9 gigabytes vs. 4.7 gigabytes). Currently, DL media is only commonly found as “+R” media, although “-R” dual layer media has been approved and may be found on the market in the future. The long term reliability and compatibility of DL recording is unproven, although my own experiences with it so far have been good.

DVD Ram is an older format that you can pretty much ignore.

HD DVD and Blu-Ray (BR or BD) are specifications for future drives with very high capacity (25 to 100 gigabytes), however neither one of them is currently in production and on the market as drives that you can add to a PC (however that will change in a matter of months). At this time, HD DVD and BR are totally incompatible and neither format will work on any drives designed for the other format. However, I would not be surprised to see “dual format” drives for these two formats at some point, but it’s years away, since even the single format drives are not yet on the market.

As for your purchase decision, you want a dual-layer, dual format drive. This will do just about anything, it supports all of the formats. However, virtually all drives currently being manufactured fit this description, so it doesn’t do much to help you narrow the choices. The top brands of drives, in my opinion, are Pioneer, NEC, Sony, Benq (Acer) and LG (other users will have their own preferences and ranking).

One thing you didn’t ask about is “Lightscribe”, which is a technology for writing a “label” to the non-data side of the media. To do this you need a drive that supports this and special “lightscribe” media that has a laser photosensitive surface on the label side. Whether or not this is of value to you is a personal choice, but keep in mind the time required to use this feature, not only to write the label side, but to design and compose it as well. Lightscribe drives are now available from several vendors.

Submitted by: Barry W. of North Canton, OH
From http://reviews.cnet.com/5208-10149-0.html?forumID=7&threadID=151177&messageID=1683716&tag=nl.e497