What is MPEG-2 AAC ?
MPEG Advanced Audio Coding (AAC), also known as MPEG-2 NBC (Non-Backward Compatible) represents the actual state of the art in natural audio coding. It is able to handle a lot more channels than MP2 or MP3 (48 full audio channels and 16 low frequency enhancement ones compared to 5 full audio channels and 1 low frequency enhancement one for MP2 or MP3), and it can handle higher sampling frequencies than MP3 (up to 96kHz compared to 48kHz). MPEG formal listening tests have demonstrate that for 2 channels it is able to provide slightly better audio quality at 96 kb/s than layer-3 at 128 kb/s or layer-2 at 192 kb/s.