Currently, there are more than 10 standards that define the way CDs store different types of information. Many of these, such as CD-I (Compact Disc-Interactive), are older formats that were designed to combine audio, text, or graphics data and were developed for use with proprietary hardware, so you really don’t need to worry about them. We’ll take a look at the primary formats currently used for audio and data CDs here.
CDs were originally developed as a replacement for vinyl records and were later adapted to store other types of information, such as computer data and photos. Information on an audio CD is stored in tracks, rather than in files like on a hard disk. In Windows Explorer, the tracks appear as 1-KB files with a .cda extension (Track01.cda, Track02.cda, etc.). In the Mac Finder, the tracks appear as .aiff files.
Some newer audio CDs support an extension to the Red Book standard called CD Text, which can contain information such as the album title and artist name. Most standalone CD players can’t read CD Text information, but CD Text capability is common in the CD players found in many high-end car stereos.
The Red Book standard specifies the format for audio CDs. This standard is also referred to as CD-DA (Compact Disc-Digital Audio). Red Book Audio is simply PCM (a common uncompressed format) audio with a resolution of 16 bits, a sampling rate of 44.1 kHz, and two channels. Audio CDs have the advantage of being playable almost anywhere, though ...