Advanced Audio Coding: Difference between revisions
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See also [[Understanding AAC]]. | See also [[Understanding AAC]]. | ||
== 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 07:05, 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.
- See also
- MP3PRO that also uses SBR.
- MPEG Surround that can used for all audio but especially MP3/mp3PRO and AAC/aacPlus. MPEG Surround technology share similar characteristics with SBR (Spectral Band Replication) and PS (Parametric Stereo), which MP3PRO and AAC+ decoders also use. DivX Inc. is one company that uses MPEG Surround technology to achieve 5.1 channel surround sound in smaller files.