AAC is the abbreviation for Advanced Audio Coding, a lossy digital audio data compression and encoding system developed by the MPEG group, as the basis of MPEG-4 and other Internet, wireless, and digital broadcast systems, and intended as the successor to MP3. Claimed improvements over MP3 include more (and higher) sample frequencies, up to 48 channels, increased coding efficiency, improved high-frequency response over 16 kHz, and more. A wide variety of hardware and software devices support AAC, most notably Apple’s iTunes and iPods.
AAC has been standardized by ISO and IEC, as part of the MPEG-2 and MPEG-4 specifications. Part of AAC, HE-AAC (AAC+), is part of MPEG-4 Audio and also adopted into digital radio standards DAB+ and Digital Radio Mondiale, as well as mobile television standards DVB-H and ATSC-M/H.