The biggest single reason why DVD recording has not taken off as quickly is perhaps what the press bills as the "Format Wars".
There is big money to be made in terms of licensing of recordable media standards. This is why several different companies have formed two different groups to promote their own DVD recordable format.
The compatibility of these formats are discussed further on in this article.
DVD-R/RW, created by Pioneer, is support by the DVD-Forum industry group. DVD+R/RW, created by Sony and HP, is the format of choice of the DVD+RW Alliance industry group. Despite what you may hear from both camps, neither groups are "official" groups. And to add to the confusion, DVD-RAM, which is supported by the DVD-Forum, is also being promoted, although it is mainly intended for data storage and has the least compatibility with DVD-ROM and DVD-Video. The DVD-Forum does sound the most official, since they were responsible for mapping out the DVD-ROM and DVD-Video formats, and are also behind the now familiar DVD logo that you see plastered everywhere these days. Despite what you may have read, compatibility for DVD-R/RW and DVD+R/RW with existing DVD devices is quite similar, and nowhere near 100%.
DVD-R was the first format to be introduced. At that time, a SCSI DVD-R burner would set you back well over $10,000. DVD burners these days retail for less than $300. While you may think that this is a huge price drop, it actually isn't. Professional DVD-R burners still costs $10,000, mainly because these can be used in the duplication of DVD movies (hence, a favorite of DVD pirates). The type of DVD-R burners that are retailing for the lower cost use "General Use" DVD-Rs, which cannot be used to duplicate DVDs, because they cannot duplicate CSS encrypted DVDs (and pretty much all commercial DVD movies use CSS encryption).
DVD-RW is the re-writable version of DVD-R. DVD-RW can be written only about 1000 times. More precisely, each sector on the DVD media can be written 1,000 times.
DVD-R media is probably the cheapest on the market right now, mainly because it was released earlier than DVD+R, and this is the only reason for the price differences at the moment (there aren't any technological or production reasons why one format is cheaper or more expensive than the other). DVD-R media (standard 2x) can be found for $US 1.50, and DVD-RW can be found for $US 3 (as of January 2003). Double sided DVD-R media (9.4 GB) are also available, with an added cost, of course.
The maximum writing speed of DVD-R recorders is 4x (5,540 KB/s). DVD-RW are written to at 2x (2,770 KB/s).
DVD+R/RW, as mentioned earlier, is the brain child of the DVD+RW Alliance group. DVD+RW was actually the first released format, with DVD+R coming in later to compete with DVD-R. Both formats are similar to their DVD- counterparts, and so the only real difference that separates these formats is the fact that they are being supported by different industry groups.
DVD+ media costs more than DVD- media at the moment, mainly because it was released at a later date - current prices (as of January 2003) for DVD+R media is between $US 2 and 3, while DVD+RW can be found for between $US 3 to 4. Prices should drop to around the same level as DVD- within this year.
DVD+RW media supports random read and write, allowing Windows drag and drop type of file copying. It also supports defect management - more about that later on. DVD+RW media, like DVD-RW, can only be written to about 1000 times.
The maximum writing speed of DVD+R recorders is 2.4x (3324 KB/s). DVD+RW are also written to at 2.4x. Note that a 4x DVD+R drive will be released in Q1 2003.
DVD-RAM was the very first re-writable format on the market. Unlike DVD-RW and DVD+RW, DVD-RAM relies on a cartridge/caddy system, which instantly makes them physically incompatible with many existing DVD devices. DVD-RAM comes in either single sided variety (4.7 GB) or double sided (9.4 GB).
DVD-RAM media are the most expensive, costing more than $US 7 per 4.7 GB disc.
DVD-RAM media also supports random read and write and defect management. DVD-RAM media can be over-written about 100,000 times, much better compared to the 1000 times that DVD-RW and DVD+RW supports.
The Best of Both Worlds :
There is, however, a simple solution to the problem of deciding the format of your choice - get a DVD recorder that supports all of them. While such a recorder doesn't actually exist at the moment, there are however DVD recorders that support more than one standard.
Take Sony's new DRU500A drive - this DVD recorder drive supports the DVD+R/RW standard (which is understandable, since Sony was one of the companies behind the creation of this standard), but a little more surprisingly, it also supports the competing DVD-R/RW.
There is also Panasonic's new Multi Drive, which supports both DVD-R/RW and DVD-RAM.
Comparison Table :
The below is a table that compares the attributes of the various DVD recording formats discussed on this page. Note that we have yet to discuss in detail performance and compatibility attributes of these standards, and our opinion of which format is best will not be made until the end of this article.