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MPEG-4 Audio Lossless Coding (ALS) - MultimediaWiki
<!DOCTYPE html> <html class="client-nojs" lang="en" dir="ltr"> <head> <meta charset="UTF-8"/> <title>MPEG-4 Audio Lossless Coding (ALS) - MultimediaWiki</title> <script>document.documentElement.className="client-js";RLCONF={"wgBreakFrames":false,"wgSeparatorTransformTable":["",""],"wgDigitTransformTable":["",""],"wgDefaultDateFormat":"dmy","wgMonthNames":["","January","February","March","April","May","June","July","August","September","October","November","December"],"wgRequestId":"558ef1a995ae306d2cb6c92f","wgCSPNonce":false,"wgCanonicalNamespace":"","wgCanonicalSpecialPageName":false,"wgNamespaceNumber":0,"wgPageName":"MPEG-4_Audio_Lossless_Coding_(ALS)","wgTitle":"MPEG-4 Audio Lossless Coding (ALS)","wgCurRevisionId":12053,"wgRevisionId":12053,"wgArticleId":2507,"wgIsArticle":true,"wgIsRedirect":false,"wgAction":"view","wgUserName":null,"wgUserGroups":["*"],"wgCategories":["Audio Codecs","Lossless Audio 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vector-feature-language-in-header-enabled vector-feature-language-in-main-page-header-disabled vector-feature-language-alert-in-sidebar-disabled vector-feature-sticky-header-disabled vector-feature-sticky-header-edit-disabled vector-feature-table-of-contents-disabled vector-feature-visual-enhancement-next-disabled"><div id="mw-page-base" class="noprint"></div> <div id="mw-head-base" class="noprint"></div> <div id="content" class="mw-body" role="main"> <a id="top"></a> <div id="siteNotice"></div> <div class="mw-indicators"> </div> <h1 id="firstHeading" class="firstHeading mw-first-heading"><span class="mw-page-title-main">MPEG-4 Audio Lossless Coding (ALS)</span></h1> <div id="bodyContent" class="vector-body"> <div id="siteSub" class="noprint">From MultimediaWiki</div> <div id="contentSub"><span class="mw-redirectedfrom">(Redirected from <a href="/index.php?title=MPEG-4_ALS&redirect=no" class="mw-redirect" title="MPEG-4 ALS">MPEG-4 ALS</a>)</span></div> <div id="contentSub2"></div> <div id="jump-to-nav"></div> <a class="mw-jump-link" href="#mw-head">Jump to navigation</a> <a class="mw-jump-link" href="#searchInput">Jump to search</a> <div id="mw-content-text" class="mw-body-content mw-content-ltr" lang="en" dir="ltr"><div class="mw-parser-output"><ul><li>FOURCCS: ???</li> <li>Company: <a href="/index.php/Moving_Picture_Experts_Group" title="Moving Picture Experts Group">MPEG</a>/NUe Group</li> <li>Homepage: <a rel="nofollow" class="external free" href="http://www.nue.tu-berlin.de/menue/forschung/projekte/beendete_projekte/mpeg-4_audio_lossless_coding_als/parameter/en/">http://www.nue.tu-berlin.de/menue/forschung/projekte/beendete_projekte/mpeg-4_audio_lossless_coding_als/parameter/en/</a></li> <li>Reference Software: <a rel="nofollow" class="external free" href="http://www.nue.tu-berlin.de/fileadmin/fg97/Forschung/Projekte/Beendete_Projekte/MPEG4_ALS/mp4alsRM22rev2.zip">http://www.nue.tu-berlin.de/fileadmin/fg97/Forschung/Projekte/Beendete_Projekte/MPEG4_ALS/mp4alsRM22rev2.zip</a></li> <li>Whitepaper: <a rel="nofollow" class="external free" href="http://elvera.nue.tu-berlin.de/files/0737Liebchen2005.pdf">http://elvera.nue.tu-berlin.de/files/0737Liebchen2005.pdf</a></li> <li>Specification: ISO/IEC 14496-3:2009 (<a rel="nofollow" class="external text" href="http://www.itscj.ipsj.or.jp/sc29/open/29view/29n6475t.doc">Draft</a>) <ul><li>Simple profile: ISO/IEC 14496-3:2009/PDAM 2 (<a rel="nofollow" class="external text" href="http://www.itscj.ipsj.or.jp/sc29/open/29view/29n10483t.doc">Draft</a>)</li></ul></li></ul> <p>ALS is MPEG-4's pure lossless audio codec. It is based on the older LPAC (<a href="/index.php/Lossless_Predictive_Audio_Coding" title="Lossless Predictive Audio Coding">Lossless Predictive Audio Coding</a>) codec from NUe. </p> <div id="toc" class="toc" role="navigation" aria-labelledby="mw-toc-heading"><input type="checkbox" role="button" id="toctogglecheckbox" class="toctogglecheckbox" style="display:none" /><div class="toctitle" lang="en" dir="ltr"><h2 id="mw-toc-heading">Contents</h2><span class="toctogglespan"><label class="toctogglelabel" for="toctogglecheckbox"></label></span></div> <ul> <li class="toclevel-1 tocsection-1"><a href="#Format"><span class="tocnumber">1</span> <span class="toctext">Format</span></a> <ul> <li class="toclevel-2 tocsection-2"><a href="#File_Header"><span class="tocnumber">1.1</span> <span class="toctext">File Header</span></a></li> <li class="toclevel-2 tocsection-3"><a href="#AUX_block"><span class="tocnumber">1.2</span> <span class="toctext">AUX block</span></a></li> <li class="toclevel-2 tocsection-4"><a href="#Data_block"><span class="tocnumber">1.3</span> <span class="toctext">Data block</span></a></li> </ul> </li> </ul> </div> <h2><span class="mw-headline" id="Format">Format</span></h2> <p>All integers are big-endian unless specified otherwise </p> <h3><span class="mw-headline" id="File_Header">File Header</span></h3> <pre> 4 bytes - 'ALS\0' 32 bits - sample rate 32 bits - samples 16 bits - channels-1 8 bits - flags: 3 bits - file type (RAW, WAV, AIFF) 3 bits - (bpp - 1)/8 1 bit - floating point 1 bit - samples are big-endian 16 bits - frame length-1 8 bits - seek info in each n-th frame 32 bits - flags: 2 bits - seek location 1 bit - adaptive order 2 bits - coding table 1 bit - pitch 10 bits - pred order 2 bits - block switching depth - 2 1 bit - BGMC or Rice 1 bit - subblock partition 1 bit - joint stereo 1 bit - multi-channel coding 1 bit - channel config 1 bit - channel sort 1 bit - CRC 1 bit - RLSLMS 5 bits - reserved 1 bit - AUX data present if(channel config bit is set) 16 bits - configuration if(channel sort bit is set) log2(channels-1)*channels/8+1 bytes 32 bits - header size 32 bits - trailer size <HEADER> <TRAILER> <CRC> Random access table <AUX> </pre> <h3><span class="mw-headline" id="AUX_block">AUX block</span></h3> <p>This block contains data not used by decoder (like cuesheet or image?) First 32 bits specify data size. </p> <h3><span class="mw-headline" id="Data_block">Data block</span></h3> <pre> if(some seek condition) 32 bits - seek size if(multichannel && joint) 8 bits - mcc flag if(subblocks flag is set) 8-32 bits - flags 1 bit - coupling off 1 bit - block size is N 2 bits - subblocks size is N/2 4 bits - subblocks size is N/4 if subblock depth > 3 8 bits - subblocks size is N/8 if subblock depth > 4 16 bits - subblocks size is N/16 </pre> <p>Block data: </p> <pre> 2 bits - block type (0 - zero block, 1 - constant, else - normal block) if(constant block) 6 bits - padding 8-32 bits - sample to fill this block (for 16-bit sample is stored in little-endian) </pre> <!-- NewPP limit report Cached time: 20241128025517 Cache expiry: 86400 Reduced expiry: false Complications: [show鈥恡oc] CPU time usage: 0.005 seconds Real time usage: 0.006 seconds Preprocessor visited node count: 14/1000000 Post鈥恊xpand include size: 0/2097152 bytes Template argument size: 0/2097152 bytes Highest expansion depth: 2/100 Expensive parser function count: 0/100 Unstrip recursion depth: 0/20 Unstrip post鈥恊xpand size: 0/5000000 bytes --> <!-- Transclusion expansion time report (%,ms,calls,template) 100.00% 0.000 1 -total --> <!-- Saved in parser cache with key multimediawiki_1_39_5-multimediawiki_:pcache:idhash:2507-0!canonical and timestamp 20241128025517 and revision id 12053. --> </div> <div class="printfooter" data-nosnippet="">Retrieved from "<a dir="ltr" href="https://wiki.multimedia.cx/index.php?title=MPEG-4_Audio_Lossless_Coding_(ALS)&oldid=12053">https://wiki.multimedia.cx/index.php?title=MPEG-4_Audio_Lossless_Coding_(ALS)&oldid=12053</a>"</div></div> <div id="catlinks" class="catlinks" data-mw="interface"><div id="mw-normal-catlinks" class="mw-normal-catlinks"><a href="/index.php/Special:Categories" title="Special:Categories">Categories</a>: <ul><li><a href="/index.php/Category:Audio_Codecs" title="Category:Audio Codecs">Audio Codecs</a></li><li><a href="/index.php/Category:Lossless_Audio_Codecs" title="Category:Lossless Audio Codecs">Lossless Audio Codecs</a></li></ul></div></div> </div> </div> <div id="mw-navigation"> <h2>Navigation menu</h2> <div id="mw-head"> <nav id="p-personal" class="vector-menu mw-portlet mw-portlet-personal vector-user-menu-legacy" aria-labelledby="p-personal-label" role="navigation" > <h3 id="p-personal-label" class="vector-menu-heading " > <span class="vector-menu-heading-label">Personal tools</span> </h3> <div class="vector-menu-content"> <ul class="vector-menu-content-list"><li id="pt-login" class="mw-list-item"><a href="/index.php?title=Special:UserLogin&returnto=MPEG-4+Audio+Lossless+Coding+%28ALS%29" title="You are encouraged to log in; however, it is not mandatory [o]" accesskey="o"><span>Log in</span></a></li></ul> </div> </nav> <div id="left-navigation"> <nav id="p-namespaces" class="vector-menu mw-portlet mw-portlet-namespaces vector-menu-tabs vector-menu-tabs-legacy" aria-labelledby="p-namespaces-label" role="navigation" > <h3 id="p-namespaces-label" class="vector-menu-heading " > <span class="vector-menu-heading-label">Namespaces</span> </h3> <div class="vector-menu-content"> <ul class="vector-menu-content-list"><li id="ca-nstab-main" class="selected mw-list-item"><a href="/index.php/MPEG-4_Audio_Lossless_Coding_(ALS)" title="View the content page [c]" accesskey="c"><span>Page</span></a></li><li id="ca-talk" class="new mw-list-item"><a href="/index.php?title=Talk:MPEG-4_Audio_Lossless_Coding_(ALS)&action=edit&redlink=1" rel="discussion" title="Discussion about the content page (page does not exist) [t]" accesskey="t"><span>Discussion</span></a></li></ul> </div> </nav> <nav id="p-variants" class="vector-menu mw-portlet mw-portlet-variants emptyPortlet vector-menu-dropdown" aria-labelledby="p-variants-label" role="navigation" > <input type="checkbox" id="p-variants-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-p-variants" class="vector-menu-checkbox" aria-labelledby="p-variants-label" /> <label id="p-variants-label" aria-label="Change language variant" class="vector-menu-heading " > <span class="vector-menu-heading-label">English</span> </label> <div class="vector-menu-content"> <ul class="vector-menu-content-list"></ul> </div> </nav> </div> <div id="right-navigation"> <nav id="p-views" class="vector-menu mw-portlet mw-portlet-views vector-menu-tabs vector-menu-tabs-legacy" aria-labelledby="p-views-label" role="navigation" > <h3 id="p-views-label" class="vector-menu-heading " > <span class="vector-menu-heading-label">Views</span> </h3> <div class="vector-menu-content"> <ul class="vector-menu-content-list"><li id="ca-view" class="selected mw-list-item"><a href="/index.php/MPEG-4_Audio_Lossless_Coding_(ALS)"><span>Read</span></a></li><li id="ca-viewsource" class="mw-list-item"><a href="/index.php?title=MPEG-4_Audio_Lossless_Coding_(ALS)&action=edit" title="This page is protected. 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