
MPEG-4 SLS, or MPEG-4 Scalable to Lossless as per
ISO/
IEC 14496-3:2005/Amd 3:2006 (Scalable Lossless Coding),
is an extension to the
MPEG-4 Part 3 (
MPEG-4
MPEG-4 is a group of international standards for the compression of digital audio and visual data, multimedia systems, and file storage formats. It was originally introduced in late 1998 as a group of audio and video coding formats and related ...
Audio) standard to allow
lossless
Lossless compression is a class of data compression that allows the original data to be perfectly reconstructed from the compressed data with no loss of information. Lossless compression is possible because most real-world data exhibits statistic ...
audio compression scalable to
lossy
In information technology, lossy compression or irreversible compression is the class of data compression methods that uses inexact approximations and partial data discarding to represent the content. These techniques are used to reduce data size ...
MPEG-4 General Audio coding methods (e.g., variations of
AAC). It was developed jointly by the Institute for Infocomm Research (I
2R) and
Fraunhofer, 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).
MPEG-4 SLS allows having both a
lossy
In information technology, lossy compression or irreversible compression is the class of data compression methods that uses inexact approximations and partial data discarding to represent the content. These techniques are used to reduce data size ...
layer and a lossless correction layer similar to
Wavpack Hybrid,
OptimFROG DualStream and
DTS-HD Master Audio
DTS-HD Master Audio (DTS-HD MA; known as DTS++ before 2004) is a multi-channel, lossless audio codec developed by DTS as an extension of the lossy DTS Coherent Acoustics codec (DTS CA; usually itself referred to as just DTS). Rather than be ...
, providing backwards compatibility to