DVDs and CDs

Digital Versatile Discs (DVDs)

DVDs let you store a lot more data than CDs. Most single-layer DVDs store 4.7GB of data and come in recordable (once only) or rewritable (many times) formats. Dual-layer DVDs will hold 8.5GB.

DVD multi-drives (which can read and write DVDs) are the most commonly available computer drive and most are compatible with the dual-layer format.

DVD formats

There are several competing formats for recording DVDs: DVD-R/RW, DVD+R/RW and DVD-RAM. Most computer drives will play all formats except DVD-RAM, a very rare and more business-oriented type.

DVD-R/RW and DVD+R/RW
When recordable DVDs first appeared, two rival groups came up with their own versions, hence the -/+ symbols. There’s no practical difference between them and new computers can handle both formats.

The R DVDs are only writeable once, but RW DVDs are re-writable. To back up files using R you'll need to use many discs. The RW format allows you to update the same disc over and over.

DVD-R DL / DVD+R DL (dual-layer)
Dual layer DVDs are able to store around twice the data of a single-layer DVD - usually 8.5GB. But they are only available in the writable R format, not the re-writable RW type. Dual layer DVD drives are newer so check that your computer can read dual-layer discs before purchasing. While they can store twice as much data as a single-layer DVD, they’re often more than double the price.

Which format to choose

The format you choose will be decided largely by the drive your computer has. Multi-format drives which read and write DVD-R/RW and DVD+R/RW discs are common.
 
If you plan to use a drive to record movies and show off your video-editing skills, DVD-R/RW and DVD+R/RW are the best options. They will play in stand-alone DVD players and other computer DVD drives.

In general, as long as you choose a drive that records a "write-once" format as well as rewritable discs, you shouldn't need to get too hung up on which + or - format to choose.

Price (approximate)

• DVD R single-layer 4.7GB: $0.90
• DVD RW single-layer 4.7GB: $1.50
• DVD R dual-layer 8.5GB: $3.50
   

Compact Discs (CDs)

CDs are an older optical disc and can store only a small amount of data compared with DVDs. CDs can store a maximum of 700MB compared with 4.7GB for a single-layer DVD.

Like DVDs, you can buy CDs in recordable or rewritable formats. Most CD R discs have a similar writing speed but RW discs can vary in speed from x4 to x24 – the higher the number, the faster it will write.

Most new computers have DVD multi-drives, but these are still able to read and write CDs.

Price (approximate)

• CD R 700MB: $0.50
• CD RW 700MB: $1.10

Blu-ray Discs (BD)

Blu-ray is a high definition video disc that is able to store 25GB on a single-layer, or 50GB on a dual-layer disc. DVDs have a maximum resolution of 720 x 576 pixels whereas Blu-ray discs can display 1920 x 1080 pixels. This makes Blu-ray discs ideal for those who want to store movies or their home videos in high definition.

Blu-ray discs come in a recordable R format or a rewritable RE format. Blu-ray drives are rare on new computers but are becoming more common.

Price (approximate)

• BD R 25GB: $14-18
• BD RE 25GB: $24