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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]] under the '''High Efficiency AAC''' ('''HE-AAC''') name.
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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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| ===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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