AAC

Advanced Audio Coding (AAC) is a lossy digital audio compression scheme, approximately four times more efficient than MP3 (the MPEG-2 Part 3 audio codec). AAC is most widely used by iOS devices (iPod touch, iPad and iPhone) and the accompanying iTunes music library, but its High Efficiency (HE-AAC) version continues to make inroads into music subscription services as well as Apple HTTP Live Streaming (HLS) audio and video streaming delivery.