MPEG Layer 3 Audio. A popular open-standard compression and file format for digital audio.

RealNetworks' audio format.

Secure RealAudio format.

Advanced Audio Coding MPEG Layer 4 Audio: The newest generation of open-standard audio compression and successor to the 10-yr old MP3 standard. It is the core of a series of different file-types such as 3GPP and MPEG-4 and provides higher quality sound as well as multi-channel (surround sound) support. RealNetworks, amongst others, used this standard for developing their latest generation high-quality audio options.

Digital Rights Management protected AAC files purchased from Apple's Music Store.

Windows Media audio file. Microsoft Windows proprietary audio format.

A music file format. Wave files are uncompressed and tend to be much larger than RealAudio or MP3 files.

A music file format. Wave files are uncompressed and tend to be much larger than RealAudio or MP3 files.

.CDA is not officially a file format. It is a small reference file used by CDs to locate audio on the CD. The actual file format on a CD is raw audio; either .PCM or .WAV format.