HE-AAC is a lossy compression method for digital audio data that requires a license. HE-AAC is a next-stage development of the AAC standard and supports up to 48 channels with full bandwidth as well as additional data. HE-AAC delivers relatively good results also at low bit rates, making it especially well suited for streaming applications and mobile telephony.
Two versions of HE-AAC are now available: HE-AAC v1 and HE-AAC v2. In contrast to version 1, version 2 additionally uses a method named parametric stereo (PS) when compressing stereo signals by means of which stereo signals can be compressed more effectively. PS therefore does not offer any advantage for mono signals.