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| − | '''High Efficiency AAC aka HE-AAC aka aacPlus'''
| + | #redirect[[Advanced_Audio_Coding]] |
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| − | '''aacPlus''' is a [[lossy data compression]] scheme for [[audio stream]]s. It is based on [[MPEG-4]], and combines three techniques: [[Advanced Audio Coding]] (AAC), [[Spectral Band Replication]] (SBR), and [[parametric stereo]] (PS).
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| − | aacPlus was standardized by the [[MPEG]] as part of the MPEG-4 Part 3 specification, under the '''High Efficiency AAC''' ('''HE-AAC''') name.
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| − | For details on the MPEG-4 Part 3 specification, see [http://en.wikipedia.org/wiki/MPEG-4_Part_3 wikipedia:MPEG-4_Part_3].
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| − | The [[codec]] can operate at very low bitrates and is good for [[Internet radio]] streaming. A 48 kilobit-per-second stream is considered to have higher quality than 128 [[kbit/s]] [[MP3]].
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| − | In HE-AAC, Spectral Band Replication (SBR) technology has been applied to AAC, and was incorporated into the standard to form High Efficiency AAC v1 (HE-AAC v1), (sometimes known as aacPlus v1).
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| − | Another recent introduction to AAC is Parametric Stereo ( aacPlus v2 or Enhanced aacPlus ). These technologies significantly improve the performance of AAC at lower bitrates, and are used, for example, in Digital Radio Mondiale .
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| − | ====Support====
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| − | HE-AAC is supported in the [[free software|free]] [[FAAD2|FAAD2 decoding library]], and hence in many free players, and in [[Winamp]] and [[foobar2000]].
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| − | ==See also==
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| − | *[[.m4a|.m4a file extension]] (the "mpeg4-audio" extenstion popularized by Apple iTunes)
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| − | ===External links===
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| − | * [http://www.tuner2.com/ Tuner2.com] list of Internet radio stations using aacPlus
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| − | * [http://www.codingtechnologies.com/products/aacPlus.htm aacPlus explained]
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| − | * [http://www.audiocoding.com/ Open Source AAC codec] FAAC (encoder) and FAAD2 (decoder)
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