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DVR-R , DVD+R, DVD-RAM: What's the Difference?

DVR-R , DVD+R, DVD-RAM: What's the Difference?

Understanding the differences meanings and reasons for the differing formats.

Home-burned DVDs are not exotic anymore. In fact, for most professionals shooting weddings and events, DVD is a required distribution format. Some confusion still exists about the various flavors of DVD available to the consumer and how this affects compatibility. The good news is that we can clear things up with one short article.

Compatibility

Before we get into any technical details about the DVD format, let us put your mind at rest with a simple statement: the factors that determine DVD compatibility rest almost entirely with the DVD player. The software you use, the computer platform, the brand of burner, the format of the discs and the brand of media all have less to do with compatibility than the standalone living room player used to play back the disc. In fact, the player effectively overrides any differences we've discovered between DVD-R and DVD+R, for example. In other words, when we've tested a $50 MegaMart DVD player and found that it plays DVD-R discs, we've found that it tends to play DVD+R discs as well.

So what are content producers to do? Of course we should try to make our discs as compatible as possible. That means doing a little research (like you are doing right now) to understand a bit more about the technology.

DVD-RAM

DVD-RAM was the first recordable and rewritable standard to hit the market and was defined by the DVD Forum (dvdforum.org), which is composed of over 220 companies. DVD-RAM discs can hold 4.7GB per side (for a total of 9.4GB on a dual-sided disc), although other sizes and capacities are available. As a rewritable format for data on a computer, DVD-RAM discs are great. Some come in a plastic cartridge or housing that makes them physically incompatible with many devices, but DVD-RAM discs are not generally compatible with living room DVD players anyhow. You will find standalone living room DVD burners using the DVD-RAM format, and even some camcorders, but you should not consider DVD-RAM to be a general-purpose distribution format for video.

DVD-R/RW

Developed by the DVD Forum, DVD-R was the first write-once format that was compatible with DVD-Video for standalone players. One of the first (relatively) inexpensive burners to burn DVD-R was the Pioneer DVR-103, the next-next-generation of which (the DVR-105) is currently well below $200 on the street. Blank DVD-R discs are also the cheapest and most widely available media format. Home-burned DVD-R discs are not any more, or less, compatible than DVD+R discs.

DVD-RW is a rewritable format that is good for data. You can also use DVD-RW media to create video discs for distribution. We have, however, found that DVD+RW is a more compatible and useful format for video. In the end, more pragmatic concerns will dominate: DVD-RW discs are more expensive (and less compatible) than DVD-R discs and are therefore not really an option for distribution anyhow.

DVD+R/RW

DVD+RW is the rewritable standard that Sony, Philips and HP (a.k.a. the DVD Alliance) originally developed to compete with DVD-RAM, and not with DVD-RW, although it is now a competitor of that format as well. Philips and Sony (both also members of the DVD Forum) argue that their non-DVD Forum-sanctioned DVD+RW format is more compatible than DVD-RW for video, and this has been verified in our tests.

DVD+R is the write-once version of DVD+RW and came out after that format was in the public domain. After some initial first-generation problems, the latest HP 300i drives are reliable and widely available to burn DVD+R discs. Not surprisingly, the DVD+R folks claim that this format is much better than DVD-R, but we have not seen this in our tests. On the other hand, we haven't found DVD+R to be any less compatible than DVD-R either.

Plus (+) or Minus (-)?

So, the choice is yours as to whether you want to go with DVD-R or DVD+R. Perhaps your decision will depend on the price of the media. Currently, DVD+R discs are slightly, but consistently, more expensive (about +25%) than DVD-R. (See our Media Price Survey sidebar.) If your budget is tight and you only need write-once for distribution, DVD-R is the format for you. If you need a rewritable format, we'd recommend you go with the DVD+RW format.

Or you can just weasel out of making any sort of commitment at all by getting a burner that swings both ways. Sony was the first to come out with DVD- R/RW/+R/RW burners, but now you can find hybrid drives from many manufacturers. The only downside is that these drives are typically at least $50 more than single-format drives, although we've seen street prices below $200.

DVD+VR

As if we needed more letters in our DVD alphabet soup, we are also seeing products with a "DVD+VR" tag on them. Don't let the new letters confuse you: DVD+VR discs are really just specially formatted DVD+RW discs. In fact, another name for DVD+VR is DVD+RW Real Time Video. Developed by the DVD+RW Alliance, the DVD+VR format allows video enthusiasts to create editable DVDs (with some limitations). The easiest way to perform the editing is by changing the table of contents on the disc without actually editing the video itself. So, for example, you could trim the beginning of a clip by simply specifying that playback starts five minutes into a video instead of from the beginning, without actually deleting any of the video. Supported by many software DVD authoring programs, the DVD+VR format is currently in use in a number of living room standalone DVD recorders. DVD+VR discs are explicitly designed to be compatible with DVD players, although they are certainly not any more compatible than the write-once formats.

General vs. Authoring Media

Authoring media is not a higher quality version of general media and uses a different laser wavelength (635nm, as compared to 650nm for general discs). You cannot burn authoring discs in drives meant for general media, and vice versa. Designed for professional use, authoring DVDs can hold information that general discs can't. For example, you can submit an authoring DVD with standardized Cutting Master Format (CMF) to a duplication house instead of a DLT (digital linear tape). Authoring burners are, of course, significantly more expensive than the general burners discussed in this article.

Stamped Discs

Why do home-burned DVDs have some compatibility problems, but Hollywood DVDs don't? The answer is that Hollywood doesn't burn DVDs, but instead stamps them out. While a burned DVD relies on changes in the color of a dye to record the digital 0s and 1s that define the disc, a stamped disc uses physical pits. Clearly, a stamped disc is the better way to go. There are even some questions about whether the dye used in burned DVDs will fade over time, although it is just speculation at this point.

In order to produce stamped discs, you'll need to contact a DVD duplication house and find out what they need. This may mean that you need to use a specific authoring application (e.g. Apple DVD Studio Pro 2.0) and output to a specific format (e.g. DLT). The DVD dupe house will then create a very expensive glass master and press out a large quantity of discs for you, perhaps a minimum of 1,000. At economies of this scale, the per disc cost is going to be very reasonable and you will get much greater compatibility than home burned discs. Besides, at the fastest burning speeds currently available, a full disc takes about 15 minutes to burn (times 1,000 discs).

Media Quality: 1X, 2X, 4X

The fastest drives now burn at 4X speeds (where 1X for DVD is 9X for CD, as far as data rate is concerned). Pragmatically, 4X means that you can burn a full DVD in under 15 minutes. But you'll need to use "4X Certified" media to hit these speeds.

Media quality is an important factor in determining compatibility with DVD players. Again, we must stress that the player itself is a much more important factor. A compatible player is likely to play both cheap discs and expensive ones, while an incompatible player will still not play even the best quality media. Media quality will make a difference with border-line players.

So, how do you find higher quality media? There are many brand names of media you can buy, from Apple to Verbatim, but in reality, there are only a very few original equipment manufacturers (OEM). Ritek is one example of a Taiwanese OEM that produces discs for the brand names you recognize. You can save money by buying OEM (generic) discs.

In most cases, these discs are not only of the same quality, but they are, in fact, exactly the same discs. Buying branded discs will give you piece of mind, however, and the additional price may be worth it. Verbatim, for example, has very high standards for the discs that it orders from Ritek, performs their own quality analysis and, perhaps most importantly for the consumer, has their phone number and guarantee on the package you buy.

One way you can identify higher quality media is by looking for the "4X Certified" guarantee. Besides giving you higher potential burning speeds with compatible burners, these discs are generally of higher quality.

The Good News and the Good News

The good news is that all of this really doesn't matter, because the format you use is transparent to the viewer. DVD burning technology is well past the first generation and prices are low. Since compatibility is determined by the player, this issue becomes less and less important with every year that passes and older players are replaced.

What are professional wedding and event videographers doing in the real world? One answer is to continue to offer your product on good old-fashioned VHS tape for clients who have an older DVD player or maybe don't have one at all. An even better solution is to give your clients a $50 DVD player that you know works with your discs. It's not as if you'll loose money doing this, just include it in your expenses.

DVD is here, now. Although we are still experiencing some minor growing pains, the worst is behind us. The future looks bright, and it is clearly dominated by shiny plastic discs.

[Sidebar: Media Costs]

Here is a survey of media costs from various sources. The lower price in the range is for OEM (generic) discs in quantities of 100, while the high price is what you might pay for one piece of branded media on the shelf at your local electronics store. Everything will have changed by the time you read this, but this should give you a rough idea of what is a reasonable price.

DVD-R$0.85 - $3.36
DVD-RW$0.98 - $6.18
DVD+R$1.29 - $3.48
DVD+RW$1.60 - $5.38
D. Eric
Franks
Thu, 10/02/2003 - 12:00am