Advanced Audio Coding (AAC) is a digital audio compression format that makes use of the lossy scheme. It is also the standardized encoding scheme for digital audio that was designed to be the successor of the MP3 format and achieves better sound quality than MP3 at similar bit rates. The format compresses much more efficiently when compared to older formats like MP3.
Its exceptional performance and quality makes it the audio codec of choice for internet, wireless and digital broadcast fields. It is also at the core of the 3GPP, 3GPP2 and MPEG-4 specifications. Standardized by ISO and IEC as part of the MPEG-4 and MPEG-2 specifications, AAC includes 48 full-bandwidth audio channels in one stream along with 16 low frequency effects channels. Around 16 coupling or dialog channels and up to 16 data streams are the other features of the format.
The format is the default or standard audio format for Apple’s iPhone, iPod, iTunes and Sony’s PlayStation 3. It is supported by Sony’s Playstation Portable and latest generation mobile phones. The improved compression achieved with the format provides higher-quality results with smaller file sizes. Support for multichannel audio, improved decoding efficiency and higher resolution audio are the other advantages of the format over MP3.
It is a wideband audio coding algorithm that makes use of two primary coding strategies for the reduction of the amount of data needed to represent high-quality digital audio. These strategies include discarding the perceptually irrelevant signal components and elimination of redundancies in the coded audio signal. The format takes a modular approach to encoding.