HE-AAC (High-Efficiency AAC, also AAC+ or aacPlus) extends AAC-LC for low bitrates by adding Spectral Band Replication (SBR). The encoder codes only the lower part of the spectrum with AAC-LC and sends a compact set of parameters that let the decoder regenerate the high frequencies, so you get usable full-bandwidth audio at 32-64 kbps where plain LC would sound dull and filtered. That efficiency made it the codec of choice for digital radio, low-bitrate streaming, and mobile. The tradeoffs are occasional 'watery' or smeared highs from the SBR reconstruction and slightly heavier decode, but support is near-universal today.
The book · Volume 4 of 7
Audio for Video: A Complete Guide to Sound in Video Products: From PCM and Codecs to Loudness, Accessibility, and Real-Time Voice Processing
HE-AAC keeps audio listenable at 32 to 64 kbps, but SBR artifacts and player support decide whether it belongs in your ladder. This volume covers HE-AAC in depth across the AAC family, from AAC-LC to xHE-AAC, with Opus and loudness metadata, so you can set audio bitrates per rendition with clear reasons. Written by Nikolay Sapunov, CEO at Fora Soft.
Choosing between HE-AAC and AAC-LC for the low-bitrate renditions of your streams?
Share your bitrate ladder and target devices and we will recommend HE-AAC or AAC-LC settings per rendition with a compatibility checklist. 250+ video products shipped since 2005.
