High Efficiency AAC (HE-AAC) is an audio coding standard that achieves low bit rates while maintaining good quality. It can encode 5.1 surround sound at 128 kbps and stereo at 48 kbps or even 32 kbps with decent quality. HE-AAC combines MPEG-4 AAC Low Complexity (LC) with Spectral Band Replication (SBR), leaving out high-frequency components, which are reconstructed using control data. It’s approximately 40% more efficient than MPEG-4 AAC LC. HE-AAC is valuable for streaming in bandwidth-constrained scenarios like digital broadcasting, mobile multimedia, and Internet radio.