Vocabulary and Disc Capacity
There are many types of CDs and DVDs available today. This section helps you to recognize and select the appropriate disc type for your use.
Compact Disc. Optical discs used for audio, video, and data storage. A standard "full size" CD is 120 mm or 4.7 inches in diameter. There are two smaller CD sizes available, a 3" disc and a Business Card CD that is rectangular in shape.
There are several ways a CD can be used:
Audio CD: An audio CD holds audio data in a specific format (two stereo channels, 16-bit audio). A 120 mm CD can generally hold either 74 minutes or 80 minutes of audio. Smaller discs hold significantly less.
Video CD (VCD): Video CDs hold video and audio information and were intended to be used on special VCD players, similar to a DVD player. The VCD became popular in some markets because they were much less expensive to make and sell than DVDs. Now that DVD media has become less costly, VCDs are declining in popularity. A VCD can hold approximately 60 minutes of audio and video, at a quality about the same as non-HD broadcast television. Most DVD players can also play VCDs.
Super Video CD (sVCD): This format is similar to VCD. The primary difference is that it stores the video with significantly higher quality (between VCD and DVD quality). As a result, each sVCD can store only about 35-100 minutes of audio and video.
Data CD: A data CD holds files and folders, similar to a hard disk or removable drive. The original CD discs could hold about 600 MB. Improved technology allows today's full-size discs to hold up to 740 MB. Mini-discs and business card CDs hold less data (in some form factors), as little as 21 MB.
A data CD can contain music and video files. This does NOT make it a music CD or a VCD. These machine-playable CD types are restricted to very specific standards. When creating a CD that you want to play in all CD players, be sure you select "Music CD" or "Audio CD" and not "Data CD".
There are also several physical types of CD:
Pressed CD: These are CDs that come pre-recorded from a factory. They cannot be changed once they are created. Most commercial music CDs are pressed.
CD-R, CD-ROM: CD-ROM stands for "CD Read Only Memory". A CD-ROM is a disc which can be burned (written) using a computer and CD-ROM drive. Up to the disc capacity can be burned on to it, and it can be read over and over, but once the disc has been formatted and written, it can never be erased.
CD-RW: A CD-RW is a CD which can be written using a computer and drive, and later erased and re-used.
Audio CD-R and Audio CD-RW: When creating an audio disc, most drives require you to use special audio-certified CD media. 3% of the cost of these discs is paid to the music industry to compensate them for the making of copies of songs.
All blank CD media will be labeled with a speed rating. These speeds are written in terms of the speed of the first CD-ROM drives. For instance, a 32X speed on a CD-R means that it can be safely written 32 times as fast as the first generation of discs and drives. Be sure to buy media that is capable of being recorded at the highest speed your drive is capable of.
When the technology was introduced, "DVD" stood for "Digital Video Disc". As more uses were found for the technology, people have started calling them "Digital Versatile Discs".
These discs are the same size as CDs, but their use of different dyes in the disc and different lasers in the drives permit them to hold much more information. A standard data DVD can store up to 4.7 GB of data, and there are dual-layer and four-layer versions that can hold up to 17 GB. These multilayer DVDs are rarely used by consumers, because for almost any application 4.7 GB is sufficient.
As with CDs, there are several ways DVDs are used:
DVD Video: A DVD video holds up to several hours of audio and video. The exact amount depends on the exact way the media were encoded for storage. The very large storage capacity of a DVD lets producers include "extras" like alternate endings, cut scenes, mini-documentaries, and extra audio tracks. The DVD standard allows the material to be enhanced with additional features like optional subtitles in several languages and multiple selectable audio tracks (for instance, multiple languages). The audio and video of a DVD video can be of high quality—significantly higher than broadcast TV.
Audio DVD: There is a standard for audio-only DVDs that store audio at extremely high quality. This format has never become popular and audio DVDs are very rarely seen (or heard).
Data DVD: Data DVDs store files and folders, very much like a hard disc or removable disc. A standard DVD holds up to 4.7 gb.
A data DVD can contain music and video files, but to be a "DVD video" it must conform exactly to a specific standard. If you would like your DVD to play on all DVD players, be sure to select "DVD video" when creating it.
There are several physical varieties of DVD manufactured:
DVD-R and DVD+R: Both of these disc types are write-once. That is, data can be written (burned) to the disc, but never erased. Once the disc is full, it can never be written to again. The DVD-R and DVD+R formats both have very similar disc capacities (about 4.7 gb for a full-size disc). DVD+R is considered to have better error-correction than DVD-R and thus resist disc damage better. DVD-R is an older format, so older DVD players are more likely to work with this type of disc. Some DVD writing drives can only burn one type of disc. Be sure that you purchase the correct media for your drive. Many modern drives are DVD±R and can read and write both formats.
DVD-RW and DVD+RW: "RW" discs can be written to, then erased and re-used. The differences between the -RW and +RW varieties are the same as for the read-only types, explained above.
The proper pronunciation of "DVD-R" is "DVD dash R", not "minus R".
The next generation of high-capacity optical disc is Blu-Ray. A 120 mm Blu-Ray disc can hold up to 50 gb of data. Video Blu-Ray discs are used for high definition video. Because the Blu-Ray standard is still very new, drives and players are still quite expensive. Blu-Ray will be supported in a future version of DVD Author Plus.
This table shows the major types of disc available, along with their capacities. DVD Author Plus supports all these disc types.
|DVD, Single Layer
|DVD, Dual Layer
|mini-DVD, Single Layer
|CD-R / CD-RW (74 minute)
|CD-R / CD-RW (80 minute)
|Business Card CD
||30-100 mb (varies)|
||21-210 mb (varies)|