Dual-Layer vs. Double-Sided DVDs

Recordable DVDs are available in several different formats to accommodate various uses and capacities. Two of the most popular types are dual-layer and double-sided DVDs. Each format has a total of two recordable layers, holds an enormous amount of data, and looks identical to the other, but dual-layer and double-sided mean two very different things. 

Dual-layer (DL) recordable DVDs come in two formats:

• DVD-R DL 
• DVD+R DL

Both have only one side, but that single side has two layers to which data can be written. Together, the two layers hold a total of up to 8.5GB, or about four hours of video. Thus, either option is ideal for most home or business uses.

The "R" in the acronyms above refer to technical differences in how data is recorded and read, but you won't notice much difference between the two. Check your DVD burner's documentation to make sure it includes support for DVD-R DL, DVD+R DL, or both.

As the name implies, double-sided (DS) recordable DVDs can hold data on two sides, each of which has a single layer. A double-sided DVD holds roughly 9.4GB of data, which is about 4.75 hours of video.

DVD burners that support DVD+/-R/RW discs can burn to double-sided discs. All you have to do is burn to one side, flip the disc like an old LP record, and then burn to the other side.

Dual-layer and double-sided DVDs further break down into two major categories:

• Recordable — DVDs cannot be overwritten after burning.
• Rewriteable — DVDs can be erased and overwritten over and over again.

To further confuse the matter, rewriteable DVDs are available with two sides and two layers. As you might expect, such discs hold considerably more data than typical DS or DL DVDs.

Movies are typically available on single-sided, dual-layer DVDs. Many movies are sold as sets with alternate versions and extra footage spread across multiple discs, but some films come on double-sided DVDs with different content on each side. Very long movies are sometimes split between the two sides, so the viewer must flip the DVD in the middle of the film to continue watching.

Older computers are typically equipped with optical disk drives that read and burn DVDs. However, since the advent of cloud storage and digitized media, many new computers lack this feature. If you'd like to play or create DVDs using your computer, check its documentation to see which types of discs are compatible. If no optical drive is included, you can buy a standalone one.

There really isn't a clear winner here. This is one of those situations where you need to choose the right tool for the job. Chances are, you should choose a dual-layer DVD when you're burning a video DVD or need the space for a single massive file. Double-sided DVDs are a better fit for storing multiple smaller files. The two-sided design also serves to compartmentalize and organize those backed up files automatically.