Difference between revisions of "Advanced Audio Coding"

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See also [[Understanding AAC]].
See also [[Understanding AAC]].


=== Extensions ===
== Extensions ==


== AAC+ ==
=== AAC+ ===


[http://www.codingtechnologies.com/products/aacPlus.htm AACPlus] (a.k.a. AAC+) is HE-AAC + [http://www.codingtechnologies.com/products/sbr.htm SBR (Spectral Band Replication)] and aacPlus v2 means HE-AAC + [http://www.codingtechnologies.com/products/sbr.htm SBR (Spectral Band Replication)] + [http://www.codingtechnologies.com/products/paraSter.htm PS (Parametric Stereo)]. Standard HE-AAC decoders can decode aacPlus encoded files/streams but without [http://www.codingtechnologies.com/products/sbr.htm SBR] and [http://www.codingtechnologies.com/products/paraSter.htm PS] you do not get the full quality.
[http://www.codingtechnologies.com/products/aacPlus.htm AACPlus] (a.k.a. AAC+) is HE-AAC + [http://www.codingtechnologies.com/products/sbr.htm SBR (Spectral Band Replication)] and aacPlus v2 means HE-AAC + [http://www.codingtechnologies.com/products/sbr.htm SBR (Spectral Band Replication)] + [http://www.codingtechnologies.com/products/paraSter.htm PS (Parametric Stereo)]. Standard HE-AAC decoders can decode aacPlus encoded files/streams but without [http://www.codingtechnologies.com/products/sbr.htm SBR] and [http://www.codingtechnologies.com/products/paraSter.htm PS] you do not get the full quality.
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** [http://www.mpegsurround.com MPEG Surround] that can used for all audio but especially MP3/mp3PRO and AAC/aacPlus. [http://www.codingtechnologies.com/products/mpgsrnd.htm MPEG Surround technology] share similar characteristics with [http://www.codingtechnologies.com/products/sbr.htm SBR (Spectral Band Replication)] and [http://www.codingtechnologies.com/products/paraSter.htm PS (Parametric Stereo)], which [[MP3#mp3PRO|MP3PRO]] and AAC+ decoders also use. [http://www.divx.com DivX Inc.] is one company that uses MPEG Surround technology to achieve 5.1 channel surround sound in smaller files.
** [http://www.mpegsurround.com MPEG Surround] that can used for all audio but especially MP3/mp3PRO and AAC/aacPlus. [http://www.codingtechnologies.com/products/mpgsrnd.htm MPEG Surround technology] share similar characteristics with [http://www.codingtechnologies.com/products/sbr.htm SBR (Spectral Band Replication)] and [http://www.codingtechnologies.com/products/paraSter.htm PS (Parametric Stereo)], which [[MP3#mp3PRO|MP3PRO]] and AAC+ decoders also use. [http://www.divx.com DivX Inc.] is one company that uses MPEG Surround technology to achieve 5.1 channel surround sound in smaller files.


== GAIN headers ==
=== GAIN headers ===


See http://mp3gain.sourceforge.net and [[MP3#GAIN (MP3Gain) header|MP3 GAIN header]].
See http://mp3gain.sourceforge.net and [[MP3#GAIN (MP3Gain) header|MP3 GAIN header]].

Revision as of 06:05, 6 October 2007

  • FOURCCS: ????
  • Company: ISO

Specification and reference source links. http://www.3gpp.org/ftp/specs/html-info/26-series.htm ftp://ftp.tnt.uni-hannover.de/pub/MPEG/audio/mpeg4/

Intel has source for its IPP based AAC decoder: http://www.intel.com/cd/software/products/asmo-na/eng/perflib/ipp/219611.htm?prn=y

Real Networks has source for its Helix AAC fixedpoint decoder here: https://datatype.helixcommunity.org/2005/aacfixptdec

Usually stored in an MP4 container.

See also Understanding AAC.

Extensions

AAC+

AACPlus (a.k.a. AAC+) is HE-AAC + SBR (Spectral Band Replication) and aacPlus v2 means HE-AAC + SBR (Spectral Band Replication) + PS (Parametric Stereo). Standard HE-AAC decoders can decode aacPlus encoded files/streams but without SBR and PS you do not get the full quality.

GAIN headers

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