MPEG-4 Audio Lossless Coding, also known as MPEG-4 ALS, is an extension to the

MPEG-4 Part 3 MPEG-4 Part 3 or MPEG-4 Audio (formally ISO/IEC 14496-3) is the third part of the ISO/IEC MPEG-4 international standard developed by Moving Picture Experts Group. It specifies audio coding methods. The first version of ISO/IEC 14496-3 was publish ...

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. The extension was finalized in December 2005 and published as

ISO ISO is the most common abbreviation for the International Organization for Standardization. ISO or Iso may also refer to: Business and finance * Iso (supermarket), a chain of Danish supermarkets incorporated into the SuperBest chain in 2007 * Iso ...

IEC The International Electrotechnical Commission (IEC; in French: ''Commission électrotechnique internationale'') is an international standards organization that prepares and publishes international standards for all electrical, electronic and r ...

14496-3:2005/Amd 2:2006 in 2006. The latest description of MPEG-4 ALS was published as subpart 11 of the MPEG-4 Audio standard (ISO/IEC 14496-3:2019) (5th edition) in December 2019. MPEG-4 ALS combines a short-term predictor and a long term predictor. The short-term predictor is similar to FLAC in its operation - it is a quantized LPC predictor with a losslessly coded residual using Golomb Rice Coding or Block Gilbert Moore Coding (BGMC). The long term predictor is modeled by 5 long-term weighted residues, each with its own lag (delay). The lag can be hundreds of samples. This predictor improves the compression for sounds with rich harmonics (containing multiples of a single fundamental frequency, locked in phase) present in many musical instruments and human voice.

Features

* Support for PCM resolutions of up to 32-bit including floating-point * Arbitrary sampling rates * Multi-channel / multi-track support (up to 65536 channels) * Streaming * Seekable (fast random access to any part of the encoded data). * Optional storage in MP4 file format; can be multiplexed with video and other media content supported by the MP4 container. * An MPEG-4 Audio profile "ALS Simple Profile", invoked with "-sp1" in the reference encoder.

Software support

, there has not been wide acceptance of this format, possibly due to the lack of encoders and decoders available. A

reference implementation In the software development process, a reference implementation (or, less frequently, sample implementation or model implementation) is a program that implements all requirements from a corresponding specification. The reference implementation o ...

of MPEG-4 ALS encoder and decoder (mp4als - e.g. mp4alsRM23) can be obtained at the MPEG-4 ALS homepage and it was also published as ISO/IEC 14496-5:2001/Amd 10:2007/Cor 3:2009. There is a MPEG-4 ALS Decoder plugin for

Winamp Winamp is a media player for Microsoft Windows originally developed by Justin Frankel and Dmitry Boldyrev by their company Nullsoft, which they later sold to AOL in 1999 for $80 million. It was then acquired by Radionomy in 2014. Sinc ...

player. On November 11, 2009, the

FFmpeg FFmpeg is a free and open-source software project consisting of a suite of libraries and programs for handling video, audio, and other multimedia files and streams. At its core is the command-line ffmpeg tool itself, designed for processing of vid ...

open source project gained an MPEG-4 ALS decoder in its development version. Only a subset of the format is currently supported.

History

In July 2002, the Moving Picture Experts Group issued a call for proposals of lossless audio coding procedures to be sent in before December. Seven companies submitted their proposals which were examined taking into consideration compression efficiency, complexity and flexibility. By July 2003, Lossless Predictive Audio Compression (LPAC) was selected as the first draft for the future standard. The reference model was further developed under participation of the Technical University of Berlin (TUB), RealNetworks, and

Nippon Telegraph and Telephone , commonly known as NTT, is a Japanese telecommunications company headquartered in Tokyo, Japan. Ranked 55th in ''Fortune'' Global 500, NTT is the fourth largest telecommunications company in the world in terms of revenue, as well as the third la ...

(NTT).

References

External links

MPEG-4 ALS homepage - Technical University of Berlin

MPEG-4 Audio Lossless Coding (ALS) - MultimediaWiki

- NTT (2007) * ttp://www.reznik.org/software.html#ALS Technical papers describing design of residual coding and quantization algorithms in MPEG-4 ALS codec
Announcement on ACN Newswire

Technical specifications (ISO/IEC 14496-3:2005/Amd 2:2006)
(not free)
Official MPEG web site
{{Compression software implementations MPEG-4 Lossless audio codecs

Features

Software support

History

See also

References

External links