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Advanced Audio Coding (AAC)

MPEG-2 AAC (Advanced Audio Coding) is the latest MPEG standard.

AAC ? Is it really better than MP3 ?

MPEG-2 Advanced Audio Coding (AAC),
          represents the actual state of the art in audio coding.
          It is able to include up to 48 audio channels, 15 low frequency
          enhancement channels, 15 embedded data streams and has
          multi-language capability. It also offers a better compression ratio than
          layer-3.This means that compared to Layer 3, you get the same quality at 70% of the bitrate.  MPEG formal listening tests have demonstrate it is able to
          provide slightly better audioquality at 96 kb/s than layer-3 (MP3) at 128 kb/s.

AAC is more efficient than MP3 (MPEG-1 Layer 3) and is the state of the
 art in audio compression technology.
There are three AAC profiles
    • Main 
    • Low Complexity (LC)
    • Scaleable Sampling Rate(SSR)
The Main profile includes all tools available and delivers the best audio quality of the three profiles. The LC (low complexity) profile comes along with a limited Temporal Noise Shaping tool and without prediction. This reduces audio quality for some special audio signals but saves a lot of computational power in both encoding and especially decoding. The SSR profile (Scaleable Sampling Rate) is a low complexity profile with a different filterbank and a special gain control tool.
You need a Any Pentium PC 90MHz or above to decode MPEG-2 AAC in realtime.
MPEG-2 AAC is the Data Compression for the 21st Century.
An aac decoder and an aac encoder  for win32, based on the ISO
          source code are avaible, but sound quality is not yet optimized:
 Player for AAC
Encoder for AAC (Aacenc v0.2)