Digital audio in its most basic form is uncompressed, which means the information can be accessed directly by your sound card and most player programs. The CDs you purchase at your local record store contain uncompressed audio. Uncompressed audio does not require much processing power to record or play, which is why you could play audio CDs or record, play, and edit uncompressed audio on Macs and PCs about a decade before you could play compressed formats such as MP3. The main drawback of uncompressed audio is that it takes up a lot of space.
A basic rule of thumb is that uncompressed CD-quality audio (16-bit, 44.1-kHz, stereo) will take up about 10 MB of space for every minute of sound.
Technologies for compressing audio can greatly increase the effective storage capacity of any type of digital media, reduce the time it takes to download music, and allow high-quality streaming audio to work over slower Internet connections.
Most kinds of data contain redundant information that can easily be expressed ...