Advanced Audio Coding

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Revision as of 11:01, 17 February 2009 by AConverse (talk | contribs) (Describe more common flavors)
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Specification and reference source links.

Implementations with source code:

Other Notable Implementations:

Usually stored in an MP4 container.

See also Understanding AAC.

Common AAC Flavors

MPEG-2 AAC-LC

The basic subset of AAC that most other flavors and profiles are based on.

The AAC Profile (MPEG-4 AAC-LC)

MPEG-2 AAC-LC plus a Perceptual Noise Substitution (PNS) tool.

The HE-AAC Profile (v1 and v2)

HE-AAC (also known as by the Dolby trade name aacPlus) is MPEG-4 AAC-LC + SBR (Spectral Band Replication) and HE-AAC v2 (aacPlus v2) is MPEG-4 AAC-LC + SBR + PS (Parametric Stereo). Standard AAC-LC decoders can decode HE-AAC encoded files/streams but without SBR and PS you do not get the full quality.

MPEG-2/4 AAC Main

MPEG-2/4 AAC-LC plus a computationally intensive, intra-channel, inter-frame frequency domain prediction tool. The details of the prediction tool are only given in ISO/IEC 13818-7 not in ISO/IEC 14496-4. This flavor is rarely seen in the wild.

MPEG-4 AAC LTP

MPEG-4 AAC-LC plus a less computationally intensive frequency domain prediction tool. This flavor is rarely seen in the wild. Despite being an MPEG-4 only flavor it can be embedded in an ADTS stream.

Extensions

GAIN headers

See http://mp3gain.sourceforge.net and MP3 GAIN header.