What is AAC?
'''AAC''' is a file format for storing music or other sounds. It stands for Advanced Audio Coding or Advanced Audio Codec. It is used by [[Apple Inc.]] in the [[iPod]] and [[iTunes]], by [[Sony]] in the [[Walkman]], in all [[Android (operating system)|Android]] devices, in car stereos, and by many other devices. AAC is one of the standard formats that comes from the [[MPEG]] organization, the same people who invented [[MP3]]. AAC is part of the [[MPEG-2]] and [[MPEG-4]] standards. Like MP3, AAC is a compressed format. It works by removing parts of the music that people can not hear. A good AAC encoder can compress CD quality music to about 10% of its original size without affecting the perceived sound quality. == Profiles == There are several profiles (variants) of AAC. These are the most popular: * AAC LC – Standard AAC profile with no extensions. All AAC players support this profile. This is the format used by Apple (iPod / iPhone), Sony (Walkman), and many others; it takes up more space, has high audio quality, and is used for music stored on an iPod, [[CD-ROM]], or disk drive. * HE-AAC v1 – AAC with Spectral Band Replication - a more efficient format; it saves space for music sent over a network, like over the Internet or to a cell phone, although at the cost of sound quality. [[Trademark|Brand]] names for this format include aacPlus[[trademark|™]], Nero Digital™, and AAC+. A variant of this format is used for HD Radio. * HE-AAC v2 – AAC with Spectral Band Replication and Parametric Stereo - an even more efficient format for music sent over a network, although at the cost of reduced stereo separation. Brand names for this format include aacPlus™ v2, eAAC+™, and AAC+ Enhanced™. * AAC-LD - Low delay profile used for VOIP applications. Various other profiles exist, but are not commonly used. == File names == Here are some common AAC file name endings: * .aac–music only (raw file without mp4 container, uncommon) * .m4a–music and information * .m4p–music and information, with [[Digital Rights Management|DRM]] *