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High-Efficiency Advanced Audio Coding
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<p>High-Efficiency Advanced Audio Coding (HE-AAC) is an <a href="/facts/Audio_coding_format/qHAhppfD">audio coding format</a> for <a href="/facts/Lossy_data_compression/jHW7DDv3">lossy data compression</a> of <a href="/facts/Digital_audio/PgugcLAI">digital audio</a> as part of the <a href="/facts/MPEG-4/6svV1w2H">MPEG-4</a> standards. It is an extension of Low Complexity <a href="/facts/Advanced_Audio_Coding/VAG9NpI4">AAC</a> (AAC-LC) optimized for low-<a href="/facts/Bitrate/ppUNMmVd">bitrate</a> applications such as <a href="/facts/Streaming_audio/4rPhSq0Y">streaming audio</a>. </p><p>The usage profile HE-AAC v1 uses <a href="/facts/Spectral_band_replication/chlcgUpD">spectral band replication</a> (SBR) to enhance the <a href="/facts/Modified_discrete_cosine_transform/jCaDMSNY">modified discrete cosine transform</a> (MDCT) compression efficiency in the <a href="/facts/Frequency_domain/pyTVrUSq">frequency domain</a>. The usage profile HE-AAC v2 couples SBR with <a href="/facts/Parametric_Stereo/ohqqE6HU">Parametric Stereo</a> (PS) to further enhance the compression efficiency of stereo signals. </p><p>HE-AAC is defined as an <a href="/facts/MPEG-4_Audio/PIqK5dk9">MPEG-4 Audio</a> profile in <a href="/facts/International_Organization_for_Standardization/IacYR7Yg">ISO</a>/<a href="/facts/International_Electrotechnical_Commission/hSK0kjwI">IEC</a> 14496–3. HE-AAC is used in <a href="/facts/Digital_radio/X0Kp5l8E">digital radio</a> standards like <a href="/facts/HD_Radio/XtS2tNG5">HD Radio</a>, <a href="/facts/Digital_Audio_Broadcasting/9GNkj4kL">DAB+</a> and <a href="/facts/Digital_Radio_Mondiale/5ghjL3ec">Digital Radio Mondiale</a>. </p>