Q: I have a Panasonic DMR-EZ48VK recorder that I recently purchased. This is all new to me. I would like to know what disc-type I should buy for recording VCR tapes onto a DVD disc. Also, is there a different between +r and -r? -- Lisa, via e-mail.
A: Those are excellent questions. Yes, it can be a confusing (and probably a frustrating) shopping experience to browse your local electronics store and decide between all the disc spindles labeled with + and - signs. Then you notice DVD+RW, DVD-RW, dual-layer, and the elusive DVD-RAM discs that are gathering dust on the shelf but are more expensive than the rest. How does one decide which format to choose without pulling out one's hair?
The short answer: Look for DVD+R--the most compatible, cheapest option out there. Using your Panasonic DMR-EZ48VK recorder, you will be able to record up to 4 hours of decent-looking video on LP mode. Since most VHS tapes hold around 2 hours of video, you should be fine. But if you require more disc space and rewritable capabilities, continue reading.
First, let's look at the difference between + and - DVD discs and their positives and negatives (yes, pun intended). DVD-R discs are the older brethren of the two formats, developed in 1997 by the DVD Forum as a high-capacity format (what CD-R did for music, DVD-R did for video). They appear physically identical to DVD+R, store the same amount of data (4.7GB or about 2 hours of video), and work with most modern DVD recorders and players. The underlying technology, which will not be obvious to the end-user, is notably different, though. Think of DVD+R as an improvement on the DVD format. It was developed in 2002 by the DVD+RW Alliance as a then competing format for DVD-R media, with a number of significant technical improvements.
For example, according to its Wikipedia entry, "DVD+R utilizes what's called the ADIP (Address In Pregroove) system of tracking the speed of the recording, which is less susceptible to interference and error than the LPP (Land Pre Pit) system used by DVD-R, resulting in a more accurate recording at higher speeds." Also, the DVD+R system includes a better error-handling mechanism than DVD-R. What does this all mean for you?
More accurate recordings mean fewer damaged or unusable discs. Back in 1998, it was not uncommon for the first DVD recorders to spit out five or so unusable discs in one session--an experience that was made even more excruciating by the sluggish burning speeds at the time. Fortunately, today our intrepid endeavor with DVD recording is much smoother. As mentioned, DVD+R and DVD-R formats were once duking it out to be dominant in the market (like HD-DVD vs. Blu-ray). Unlike the recent format wars, however, both camps came to a mutual understanding; in 2008 DVD+R was officially accepted as a DVD format alongside DVD-R, meaning all modern DVD recorders should support both formats. The question, however, remains: which is better? If you still have a decade-old DVD player, you will need to use DVD-R media; it's the oldest and thus most compatible format of the two. DVD+R media will probably not play. However, if that's not the case, which is probably true for most customers, DVD+R is the "improved" format, producing more accurate, less error-prone recordings that can play well on all modern DVD players (from the last three years or so).
How do dual-layer discs fit into this format morass? As the name implies, DVD+R dual-layer and DVD-R dual-layer discs double the capacity by having a second layer affixed to the disc. Now you have 8.5GB (opposed to 4.5GB) of storage capacity. The price tag, however, also tends to multiply; it generally costs about $1 for a single-layer disc versus as much as $5 for a double-sided one. Compatibility can also be an issue. Many current DVD players and recorders support the format, but as previously mentioned, if you have a decade-old player, you will probably have some trouble. In the end, it's a decision between price and capacity; do you or do you not need to record 8 hours of DVD-quality video? If you do, go for DVD+R dual-layer.
And then we have DVD-RW and DVD+RW media to think about. The benefit of these discs is, of course, the ability to record and re-record data to the disc. This is particularly useful if you're recording a television program from week to week. Instead of emptying your entire spindle of DVD-R discs, which cannot be reused after they're finalized, DVD-RW discs save on the wallet and on discarded discs. On the other hand, DVD+RW discs are not as compatible as DVD+R, and are not designed to permanently back up your data. Think of this possibility: an inquisitive family member or friend accidentally deletes the precious and only video recording of your trip to Singapore. Yikes; that may be a risk you are willing to take with DVD+RWs.
Lastly, we have the odd-ball DVD-RAM format hiding in the back of the shelf. This is ironically the oldest and the least compatible of all the DVD formats. Developed in 1996, the format has had a larger presence with camcorders and set-top boxes because of the fact that data can be easily and randomly written to and erased from the disc, allowing for extensive editing. Think of DVD-RAM as similar to floppy-disc or hard disc technology; data can be randomly accessed, erased, or rewritten much more swiftly than DVD+RW. The Panasonic DMR-EZ48VK, for instance, has a feature called chasing playback that works exclusively with DVD-RAM, allowing the user to watch the beginning of a program while the unit is in the process of recording. The discs also have a longer life expectancy--as much as 30 years--and some of them come enclosed in a protective case, making the format highly reliable for backing up data. They are, however, the least compatible and most expensive DVD format out there. Amazon.com offers a single DVD-RAM disc for $19, while a 5-pack of DVD+RW discs will cost you $8.