An enhanced AAC format from Coding Technologies (www.codingtechnologies.com) that extends Low Complexity AAC (AAC LC) to deliver near CD-quality sound in as little as 32 Kbps. Also known as "High Efficiency AAC" (HE-AAC). Version 1 - AAC+ (HE-AAC v1) Using Spectral Band Replication (SBR), AAC+ is a proprietary technique that halves the sampling rate but encodes the missing higher frequencies at a rate of 1.5 Kbps and stores them in the auxiliary data fields of the MPEG format. SBR is also used in the mp3PRO format (see mp3PRO). Version 2 - eAAC+ (HE-AAC v2) Used for stereo signals, eAAC+ supports Parametric Stereo (PS), which works similar to SBR. PS encodes the differences between left and right channels as a 3 Kbps data stream that it sends along with the monaural representation of the channels. See AAC and MP3.