DVDs and Blu-rays: Difference

With the plethora of digital media flooding today's market, it's no surprise that many consumers have trouble discerning the sometimes subtle differences between one medium and another. Particularly tricky are the differences between DVD and Blu-ray Discs, especially for users of DVD copy software.

Although everyone knows that the Blu-ray Disc is gradually replacing the more outmoded DVD, and we all remember its conquest of DVD-HD in the format wars, many people are unsure as to what the difference really is. Vague assertions as to quality and storage size might come up, but for the most part, we accept that this new option is the superior format and leave it at that. To be perfectly fair, it is. But what makes it the best? What are the pros and cons of using a Blu-ray over a DVD? By reviewing a few simple facts, the differences between the two formats should become readily apparent.

Quality
Also called resolution, image quality is without a doubt the most visible aspect of a disc's abilities. This quality is typically measured in lines of pixels, with the higher numbers representing the best quality. Standard DVD format is only 480 to 520p. This is by no means poor quality; in fact, on a standard tube-style television, it's about as good as it gets. However, Blu-rays have quality that goes as high as 1080p – more than twice the resolution of a standard DVD. While this certainly looks good in print, you should bear in mind that this level of quality is only really discernible on a large, flat-screen TV or monitor. Likewise, many DVD rippers or DVD copy software applications do not support Blu-ray burning.

Data Capacity
While the exact numbers may vary, standard DVDs (or DVD 5 discs) can hold up to 4.7GB of information. This works out to be about two hours of continuous footage, or 4–5 half-hour episodes. Double-layer DVDs can hold about twice this amount of information, and these are called DVD 9 discs.

In a similar vein, there are single- and double-layer Blu-ray Discs; however, each of these discs contains far greater storage capacity. A single-layer Blu-ray Disc can hold up to 25GB of information, which equates to around 13 hours of standard-definition video, but only about two hours of high-definition video. Double-layer discs can hold up to 50GB, which translates to about 26 hours of standard definition or four-and-a-half hours of high-definition material.

Format/Compatibility
Perhaps the greatest difficulty with Blu-ray Discs has nothing to do with their quality or capacity to store information; it's simply the fact that the format isn't quite universally accepted. DVDs still comprise a sizable portion of the market in films, TV shows and other media. Part of this is due to the simple fact that some people simply don't have the means to really use Blu-ray Discs. These discs require a special player and can only really be appreciated with a large, flat-screen TV. Buyers should make sure that they have the proper electronic devices to fully appreciate this new trend in digital media.