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MPEG-4 SLS
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<p>MPEG-4 SLS, or MPEG-4 Scalable to Lossless as per <a href="/facts/International_Organization_for_Standardization/IacYR7Yg">ISO</a>/<a href="/facts/International_Electrotechnical_Commission/hSK0kjwI">IEC</a> 14496-3:2005/Amd 3:2006 (Scalable Lossless Coding), is an extension to the <a href="/facts/MPEG-4_Part_3/PIqK5dk9">MPEG-4 Part 3</a> (<a href="/facts/MPEG-4/6svV1w2H">MPEG-4</a> Audio) standard to allow <a href="/facts/Lossless_data_compression/LS702KsN">lossless</a> <a href="/facts/Audio_data_compression/gMFuY4FT">audio compression</a> scalable to <a href="/facts/Lossy/jHW7DDv3">lossy</a> MPEG-4 General Audio coding methods (e.g., variations of <a href="/facts/Advanced_Audio_Coding/VAG9NpI4">AAC</a>). It was developed jointly by the Institute for Infocomm Research (I2R) and <a href="/facts/Fraunhofer_Society/JS0cK2Qo">Fraunhofer</a>, which commercializes its implementation of a limited subset of the standard under the name of HD-AAC. Standardization of the HD-AAC profile for MPEG-4 Audio is under development (as of September 2009). </p><p>MPEG-4 SLS allows having both a <a href="/facts/Lossy/jHW7DDv3">lossy</a> layer and a lossless correction layer similar to <a href="/facts/Wavpack/MN8nT9Gj">Wavpack</a> Hybrid, <a href="/facts/OptimFROG/NHF2DoKS">OptimFROG</a> DualStream and <a href="/facts/DTS-HD_Master_Audio/zprgCEGx">DTS-HD Master Audio</a>, providing backwards compatibility to <a href="/facts/MPEG/ygmT7JBB">MPEG</a> <a href="/facts/Advanced_Audio_Coding/VAG9NpI4">AAC</a>-compliant <a href="/facts/Bitstream/Pf9oGYyY">bitstreams</a>. MPEG-4 SLS can also work without a lossy layer (a.k.a. "SLS Non-Core"), in which case it will not be backwards compatible, <a href="/facts/Lossy_compression/jHW7DDv3">Lossy compression</a> of files is necessary for files that need to be streamed to the Internet or played in devices with limited storage. </p><p>With <a href="/facts/Digital_rights_management/4AF8JmDt">digital rights management</a> (DRM), ripping of the lossless data or playback on non-DRM-enabled devices could be disabled. </p><p>MPEG-4 SLS is not related in any way to <a href="/facts/MPEG-4_ALS/ptpbl4hK">MPEG-4 ALS</a> (Audio Lossless Coding). </p>