AAC Advanced Audio Coding
More info
- Released
- Type
- Audio codec
- Spec
- ISO/IEC 13818-7
MP3's successor — better audio at the same bitrate, and the format behind iTunes, YouTube and digital radio.
Standardised in 1997 as part of MPEG-2 and extended in MPEG-4. The improvements over MP3 are technical but real: larger block size, better entropy coding, and support for up to 48 channels.
Apple chose AAC for iTunes in 2003, making it a consumer standard. HE-AAC adds spectral band replication for very low bitrates, used in DAB+ and satellite radio. Patent-encumbered, unlike Opus, which is free and better at speech.