CD-R stands for "Compact Disc Recordable." As the name suggests, these blank CDs are used to record audio and other forms of data. A CD-R can contain music, audio files, video files, pictures, spreadsheets, documents and a variety of other files, according to Osta.
Most CD-R discs can hold up to 80 minutes of audio, depending on the quality of the tracks. This accounts for up to 99 songs or tracks. The amount of music that a disc can hold also varies as to whether or not the files are compressed as MP3 tracks. If the tracks are compressed, a single CD-R can hold up to 10 or 20 whole CD albums.
Tracks and other files are placed onto a blank CD-R via a simple computer application that runs after a disc is placed into a rewritable disc drive. Certain computer applications also allow a user to compress files or change their file type before placing the data on the recordable CD. For example, MP3 files can be uncompressed to become regular CD audio tracks and vice versa. This is especially useful if the disc will be played in a regular CD player that does not support the MP3 file format.