CINXE.COM

<!DOCTYPE html> <html class="client-nojs vector-feature-language-in-header-enabled vector-feature-language-in-main-page-header-disabled vector-feature-page-tools-pinned-disabled vector-feature-toc-pinned-clientpref-1 vector-feature-main-menu-pinned-disabled vector-feature-limited-width-clientpref-1 vector-feature-limited-width-content-enabled vector-feature-custom-font-size-clientpref-1 vector-feature-appearance-pinned-clientpref-1 vector-feature-night-mode-enabled skin-theme-clientpref-day vector-sticky-header-enabled vector-toc-available" lang="en" dir="ltr"> <head> <meta charset="UTF-8"> <title>CELT - Wikipedia</title> <script>(function(){var className="client-js vector-feature-language-in-header-enabled vector-feature-language-in-main-page-header-disabled vector-feature-page-tools-pinned-disabled vector-feature-toc-pinned-clientpref-1 vector-feature-main-menu-pinned-disabled vector-feature-limited-width-clientpref-1 vector-feature-limited-width-content-enabled vector-feature-custom-font-size-clientpref-1 vector-feature-appearance-pinned-clientpref-1 vector-feature-night-mode-enabled skin-theme-clientpref-day vector-sticky-header-enabled vector-toc-available";var cookie=document.cookie.match(/(?:^|; )enwikimwclientpreferences=([^;]+)/);if(cookie){cookie[1].split('%2C').forEach(function(pref){className=className.replace(new RegExp('(^| )'+pref.replace(/-clientpref-\w+$|[^\w-]+/g,'')+'-clientpref-\\w+( |$)'),'$1'+pref+'$2');});}document.documentElement.className=className;}());RLCONF={"wgBreakFrames":false,"wgSeparatorTransformTable":["",""],"wgDigitTransformTable":["",""],"wgDefaultDateFormat":"dmy","wgMonthNames":["","January","February","March","April","May","June","July","August","September","October","November","December"],"wgRequestId":"db6e7fae-e84a-45e9-818b-f31abb0d447f","wgCanonicalNamespace":"","wgCanonicalSpecialPageName":false,"wgNamespaceNumber":0,"wgPageName":"CELT","wgTitle":"CELT","wgCurRevisionId":1221001953,"wgRevisionId":1221001953,"wgArticleId":21663936,"wgIsArticle":true,"wgIsRedirect":false,"wgAction":"view","wgUserName":null,"wgUserGroups":["*"],"wgCategories":["Webarchive template wayback links","CS1 German-language sources (de)","Articles with short description","Short description is different from Wikidata","Speech codecs","Free audio codecs","Xiph.Org projects"],"wgPageViewLanguage":"en","wgPageContentLanguage":"en","wgPageContentModel":"wikitext","wgRelevantPageName":"CELT","wgRelevantArticleId":21663936,"wgIsProbablyEditable":true,"wgRelevantPageIsProbablyEditable":true,"wgRestrictionEdit":[],"wgRestrictionMove":[],"wgNoticeProject":"wikipedia","wgCiteReferencePreviewsActive":false,"wgFlaggedRevsParams":{"tags":{"status":{"levels":1}}},"wgMediaViewerOnClick":true,"wgMediaViewerEnabledByDefault":true,"wgPopupsFlags":0,"wgVisualEditor":{"pageLanguageCode":"en","pageLanguageDir":"ltr","pageVariantFallbacks":"en"},"wgMFDisplayWikibaseDescriptions":{"search":true,"watchlist":true,"tagline":false,"nearby":true},"wgWMESchemaEditAttemptStepOversample":false,"wgWMEPageLength":20000,"wgEditSubmitButtonLabelPublish":true,"wgULSPosition":"interlanguage","wgULSisCompactLinksEnabled":false,"wgVector2022LanguageInHeader":true,"wgULSisLanguageSelectorEmpty":false,"wgWikibaseItemId":"Q1128269","wgCheckUserClientHintsHeadersJsApi":["brands","architecture","bitness","fullVersionList","mobile","model","platform","platformVersion"],"GEHomepageSuggestedEditsEnableTopics":true,"wgGETopicsMatchModeEnabled":false,"wgGELevelingUpEnabledForUser":false}; RLSTATE={"ext.globalCssJs.user.styles":"ready","site.styles":"ready","user.styles":"ready","ext.globalCssJs.user":"ready","user":"ready","user.options":"loading","ext.cite.styles":"ready","skins.vector.search.codex.styles":"ready","skins.vector.styles":"ready","skins.vector.icons":"ready","jquery.makeCollapsible.styles":"ready","ext.wikimediamessages.styles":"ready","ext.visualEditor.desktopArticleTarget.noscript":"ready","ext.uls.interlanguage":"ready","wikibase.client.init":"ready"};RLPAGEMODULES=["ext.cite.ux-enhancements","mediawiki.page.media","site","mediawiki.page.ready","jquery.makeCollapsible","mediawiki.toc","skins.vector.js","ext.centralNotice.geoIP","ext.centralNotice.startUp","ext.gadget.ReferenceTooltips","ext.gadget.switcher","ext.urlShortener.toolbar","ext.centralauth.centralautologin","mmv.bootstrap","ext.popups","ext.visualEditor.desktopArticleTarget.init","ext.visualEditor.targetLoader","ext.echo.centralauth","ext.eventLogging","ext.wikimediaEvents","ext.navigationTiming","ext.uls.interface","ext.cx.eventlogging.campaigns","ext.cx.uls.quick.actions","wikibase.client.vector-2022","ext.checkUser.clientHints","ext.quicksurveys.init","ext.growthExperiments.SuggestedEditSession"];</script> <script>(RLQ=window.RLQ||[]).push(function(){mw.loader.impl(function(){return["user.options@12s5i",function($,jQuery,require,module){mw.user.tokens.set({"patrolToken":"+\\","watchToken":"+\\","csrfToken":"+\\"}); }];});});</script> <link rel="stylesheet" href="/w/load.php?lang=en&modules=ext.cite.styles%7Cext.uls.interlanguage%7Cext.visualEditor.desktopArticleTarget.noscript%7Cext.wikimediamessages.styles%7Cjquery.makeCollapsible.styles%7Cskins.vector.icons%2Cstyles%7Cskins.vector.search.codex.styles%7Cwikibase.client.init&only=styles&skin=vector-2022"> <script async="" src="/w/load.php?lang=en&modules=startup&only=scripts&raw=1&skin=vector-2022"></script> <meta name="ResourceLoaderDynamicStyles" content=""> <link rel="stylesheet" href="/w/load.php?lang=en&modules=site.styles&only=styles&skin=vector-2022"> <meta name="generator" content="MediaWiki 1.44.0-wmf.22"> <meta name="referrer" content="origin"> <meta name="referrer" content="origin-when-cross-origin"> <meta name="robots" content="max-image-preview:standard"> <meta name="format-detection" content="telephone=no"> <meta name="viewport" content="width=1120"> <meta property="og:title" content="CELT - Wikipedia"> <meta property="og:type" content="website"> <link rel="preconnect" href="//upload.wikimedia.org"> <link rel="alternate" media="only screen and (max-width: 640px)" href="//en.m.wikipedia.org/wiki/CELT"> <link rel="alternate" type="application/x-wiki" title="Edit this page" href="/w/index.php?title=CELT&action=edit"> <link rel="apple-touch-icon" href="/static/apple-touch/wikipedia.png"> <link rel="icon" href="/static/favicon/wikipedia.ico"> <link rel="search" type="application/opensearchdescription+xml" href="/w/rest.php/v1/search" title="Wikipedia (en)"> <link rel="EditURI" type="application/rsd+xml" href="//en.wikipedia.org/w/api.php?action=rsd"> <link rel="canonical" href="https://en.wikipedia.org/wiki/CELT"> <link rel="license" href="https://creativecommons.org/licenses/by-sa/4.0/deed.en"> <link rel="alternate" type="application/atom+xml" title="Wikipedia Atom feed" href="/w/index.php?title=Special:RecentChanges&feed=atom"> <link rel="dns-prefetch" href="//meta.wikimedia.org" /> <link rel="dns-prefetch" href="auth.wikimedia.org"> </head> <body class="skin--responsive skin-vector skin-vector-search-vue mediawiki ltr sitedir-ltr mw-hide-empty-elt ns-0 ns-subject mw-editable page-CELT rootpage-CELT skin-vector-2022 action-view"><a class="mw-jump-link" href="#bodyContent">Jump to content</a> <div class="vector-header-container"> <header class="vector-header mw-header"> <div class="vector-header-start"> <nav class="vector-main-menu-landmark" aria-label="Site"> <div id="vector-main-menu-dropdown" class="vector-dropdown vector-main-menu-dropdown vector-button-flush-left vector-button-flush-right" title="Main menu" > <input type="checkbox" id="vector-main-menu-dropdown-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-main-menu-dropdown" class="vector-dropdown-checkbox " aria-label="Main menu" > <label id="vector-main-menu-dropdown-label" for="vector-main-menu-dropdown-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" ><span class="vector-icon mw-ui-icon-menu mw-ui-icon-wikimedia-menu"></span> <span class="vector-dropdown-label-text">Main menu</span> </label> <div class="vector-dropdown-content"> <div id="vector-main-menu-unpinned-container" class="vector-unpinned-container"> <div id="vector-main-menu" class="vector-main-menu vector-pinnable-element"> <div class="vector-pinnable-header vector-main-menu-pinnable-header vector-pinnable-header-unpinned" data-feature-name="main-menu-pinned" data-pinnable-element-id="vector-main-menu" data-pinned-container-id="vector-main-menu-pinned-container" data-unpinned-container-id="vector-main-menu-unpinned-container" > <div class="vector-pinnable-header-label">Main menu</div> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-pin-button" data-event-name="pinnable-header.vector-main-menu.pin">move to sidebar</button> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-unpin-button" data-event-name="pinnable-header.vector-main-menu.unpin">hide</button> </div> <div id="p-navigation" class="vector-menu mw-portlet mw-portlet-navigation" > <div class="vector-menu-heading"> Navigation </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="n-mainpage-description" class="mw-list-item"><a href="/wiki/Main_Page" title="Visit the main page [z]" accesskey="z"><span>Main page</span></a></li><li id="n-contents" class="mw-list-item"><a href="/wiki/Wikipedia:Contents" title="Guides to browsing Wikipedia"><span>Contents</span></a></li><li id="n-currentevents" class="mw-list-item"><a href="/wiki/Portal:Current_events" title="Articles related to current events"><span>Current events</span></a></li><li id="n-randompage" class="mw-list-item"><a href="/wiki/Special:Random" title="Visit a randomly selected article [x]" accesskey="x"><span>Random article</span></a></li><li id="n-aboutsite" class="mw-list-item"><a href="/wiki/Wikipedia:About" title="Learn about Wikipedia and how it works"><span>About Wikipedia</span></a></li><li id="n-contactpage" class="mw-list-item"><a href="//en.wikipedia.org/wiki/Wikipedia:Contact_us" title="How to contact Wikipedia"><span>Contact us</span></a></li> </ul> </div> </div> <div id="p-interaction" class="vector-menu mw-portlet mw-portlet-interaction" > <div class="vector-menu-heading"> Contribute </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="n-help" class="mw-list-item"><a href="/wiki/Help:Contents" title="Guidance on how to use and edit Wikipedia"><span>Help</span></a></li><li id="n-introduction" class="mw-list-item"><a href="/wiki/Help:Introduction" title="Learn how to edit Wikipedia"><span>Learn to edit</span></a></li><li id="n-portal" class="mw-list-item"><a href="/wiki/Wikipedia:Community_portal" title="The hub for editors"><span>Community portal</span></a></li><li id="n-recentchanges" class="mw-list-item"><a href="/wiki/Special:RecentChanges" title="A list of recent changes to Wikipedia [r]" accesskey="r"><span>Recent changes</span></a></li><li id="n-upload" class="mw-list-item"><a href="/wiki/Wikipedia:File_upload_wizard" title="Add images or other media for use on Wikipedia"><span>Upload file</span></a></li><li id="n-specialpages" class="mw-list-item"><a href="/wiki/Special:SpecialPages"><span>Special pages</span></a></li> </ul> </div> </div> </div> </div> </div> </div> </nav> <a href="/wiki/Main_Page" class="mw-logo"> <img class="mw-logo-icon" src="/static/images/icons/wikipedia.png" alt="" aria-hidden="true" height="50" width="50"> <span class="mw-logo-container skin-invert"> <img class="mw-logo-wordmark" alt="Wikipedia" src="/static/images/mobile/copyright/wikipedia-wordmark-en.svg" style="width: 7.5em; height: 1.125em;"> <img class="mw-logo-tagline" alt="The Free Encyclopedia" src="/static/images/mobile/copyright/wikipedia-tagline-en.svg" width="117" height="13" style="width: 7.3125em; height: 0.8125em;"> </span> </a> </div> <div class="vector-header-end"> <div id="p-search" role="search" class="vector-search-box-vue vector-search-box-collapses vector-search-box-show-thumbnail vector-search-box-auto-expand-width vector-search-box"> <a href="/wiki/Special:Search" class="cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only search-toggle" title="Search Wikipedia [f]" accesskey="f"><span class="vector-icon mw-ui-icon-search mw-ui-icon-wikimedia-search"></span> <span>Search</span> </a> <div class="vector-typeahead-search-container"> <div class="cdx-typeahead-search cdx-typeahead-search--show-thumbnail cdx-typeahead-search--auto-expand-width"> <form action="/w/index.php" id="searchform" class="cdx-search-input cdx-search-input--has-end-button"> <div id="simpleSearch" class="cdx-search-input__input-wrapper" data-search-loc="header-moved"> <div class="cdx-text-input cdx-text-input--has-start-icon"> <input class="cdx-text-input__input" type="search" name="search" placeholder="Search Wikipedia" aria-label="Search Wikipedia" autocapitalize="sentences" title="Search Wikipedia [f]" accesskey="f" id="searchInput" > <span class="cdx-text-input__icon cdx-text-input__start-icon"></span> </div> <input type="hidden" name="title" value="Special:Search"> </div> <button class="cdx-button cdx-search-input__end-button">Search</button> </form> </div> </div> </div> <nav class="vector-user-links vector-user-links-wide" aria-label="Personal tools"> <div class="vector-user-links-main"> <div id="p-vector-user-menu-preferences" class="vector-menu mw-portlet emptyPortlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> </ul> </div> </div> <div id="p-vector-user-menu-userpage" class="vector-menu mw-portlet emptyPortlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> </ul> </div> </div> <nav class="vector-appearance-landmark" aria-label="Appearance"> <div id="vector-appearance-dropdown" class="vector-dropdown " title="Change the appearance of the page's font size, width, and color" > <input type="checkbox" id="vector-appearance-dropdown-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-appearance-dropdown" class="vector-dropdown-checkbox " aria-label="Appearance" > <label id="vector-appearance-dropdown-label" for="vector-appearance-dropdown-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" ><span class="vector-icon mw-ui-icon-appearance mw-ui-icon-wikimedia-appearance"></span> <span class="vector-dropdown-label-text">Appearance</span> </label> <div class="vector-dropdown-content"> <div id="vector-appearance-unpinned-container" class="vector-unpinned-container"> </div> </div> </div> </nav> <div id="p-vector-user-menu-notifications" class="vector-menu mw-portlet emptyPortlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> </ul> </div> </div> <div id="p-vector-user-menu-overflow" class="vector-menu mw-portlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="pt-sitesupport-2" class="user-links-collapsible-item mw-list-item user-links-collapsible-item"><a data-mw="interface" href="https://donate.wikimedia.org/?wmf_source=donate&wmf_medium=sidebar&wmf_campaign=en.wikipedia.org&uselang=en" class=""><span>Donate</span></a> </li> <li id="pt-createaccount-2" class="user-links-collapsible-item mw-list-item user-links-collapsible-item"><a data-mw="interface" href="/w/index.php?title=Special:CreateAccount&returnto=CELT" title="You are encouraged to create an account and log in; however, it is not mandatory" class=""><span>Create account</span></a> </li> <li id="pt-login-2" class="user-links-collapsible-item mw-list-item user-links-collapsible-item"><a data-mw="interface" href="/w/index.php?title=Special:UserLogin&returnto=CELT" title="You're encouraged to log in; however, it's not mandatory. [o]" accesskey="o" class=""><span>Log in</span></a> </li> </ul> </div> </div> </div> <div id="vector-user-links-dropdown" class="vector-dropdown vector-user-menu vector-button-flush-right vector-user-menu-logged-out" title="Log in and more options" > <input type="checkbox" id="vector-user-links-dropdown-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-user-links-dropdown" class="vector-dropdown-checkbox " aria-label="Personal tools" > <label id="vector-user-links-dropdown-label" for="vector-user-links-dropdown-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" ><span class="vector-icon mw-ui-icon-ellipsis mw-ui-icon-wikimedia-ellipsis"></span> <span class="vector-dropdown-label-text">Personal tools</span> </label> <div class="vector-dropdown-content"> <div id="p-personal" class="vector-menu mw-portlet mw-portlet-personal user-links-collapsible-item" title="User menu" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="pt-sitesupport" class="user-links-collapsible-item mw-list-item"><a href="https://donate.wikimedia.org/?wmf_source=donate&wmf_medium=sidebar&wmf_campaign=en.wikipedia.org&uselang=en"><span>Donate</span></a></li><li id="pt-createaccount" class="user-links-collapsible-item mw-list-item"><a href="/w/index.php?title=Special:CreateAccount&returnto=CELT" title="You are encouraged to create an account and log in; however, it is not mandatory"><span class="vector-icon mw-ui-icon-userAdd mw-ui-icon-wikimedia-userAdd"></span> <span>Create account</span></a></li><li id="pt-login" class="user-links-collapsible-item mw-list-item"><a href="/w/index.php?title=Special:UserLogin&returnto=CELT" title="You're encouraged to log in; however, it's not mandatory. [o]" accesskey="o"><span class="vector-icon mw-ui-icon-logIn mw-ui-icon-wikimedia-logIn"></span> <span>Log in</span></a></li> </ul> </div> </div> <div id="p-user-menu-anon-editor" class="vector-menu mw-portlet mw-portlet-user-menu-anon-editor" > <div class="vector-menu-heading"> Pages for logged out editors <a href="/wiki/Help:Introduction" aria-label="Learn more about editing"><span>learn more</span></a> </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="pt-anoncontribs" class="mw-list-item"><a href="/wiki/Special:MyContributions" title="A list of edits made from this IP address [y]" accesskey="y"><span>Contributions</span></a></li><li id="pt-anontalk" class="mw-list-item"><a href="/wiki/Special:MyTalk" title="Discussion about edits from this IP address [n]" accesskey="n"><span>Talk</span></a></li> </ul> </div> </div> </div> </div> </nav> </div> </header> </div> <div class="mw-page-container"> <div class="mw-page-container-inner"> <div class="vector-sitenotice-container"> <div id="siteNotice"></div> </div> <div class="vector-column-start"> <div class="vector-main-menu-container"> <div id="mw-navigation"> <nav id="mw-panel" class="vector-main-menu-landmark" aria-label="Site"> <div id="vector-main-menu-pinned-container" class="vector-pinned-container"> </div> </nav> </div> </div> <div class="vector-sticky-pinned-container"> <nav id="mw-panel-toc" aria-label="Contents" data-event-name="ui.sidebar-toc" class="mw-table-of-contents-container vector-toc-landmark"> <div id="vector-toc-pinned-container" class="vector-pinned-container"> <div id="vector-toc" class="vector-toc vector-pinnable-element"> <div class="vector-pinnable-header vector-toc-pinnable-header vector-pinnable-header-pinned" data-feature-name="toc-pinned" data-pinnable-element-id="vector-toc" > <h2 class="vector-pinnable-header-label">Contents</h2> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-pin-button" data-event-name="pinnable-header.vector-toc.pin">move to sidebar</button> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-unpin-button" data-event-name="pinnable-header.vector-toc.unpin">hide</button> </div> <ul class="vector-toc-contents" id="mw-panel-toc-list"> <li id="toc-mw-content-text" class="vector-toc-list-item vector-toc-level-1"> <a href="#" class="vector-toc-link"> <div class="vector-toc-text">(Top)</div> </a> </li> <li id="toc-Properties" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Properties"> <div class="vector-toc-text"> <span class="vector-toc-numb">1</span> <span>Properties</span> </div> </a> <ul id="toc-Properties-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Technology" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Technology"> <div class="vector-toc-text"> <span class="vector-toc-numb">2</span> <span>Technology</span> </div> </a> <ul id="toc-Technology-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-History" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#History"> <div class="vector-toc-text"> <span class="vector-toc-numb">3</span> <span>History</span> </div> </a> <ul id="toc-History-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Software" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Software"> <div class="vector-toc-text"> <span class="vector-toc-numb">4</span> <span>Software</span> </div> </a> <ul id="toc-Software-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-See_also" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#See_also"> <div class="vector-toc-text"> <span class="vector-toc-numb">5</span> <span>See also</span> </div> </a> <ul id="toc-See_also-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-References" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#References"> <div class="vector-toc-text"> <span class="vector-toc-numb">6</span> <span>References</span> </div> </a> <ul id="toc-References-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-External_links" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#External_links"> <div class="vector-toc-text"> <span class="vector-toc-numb">7</span> <span>External links</span> </div> </a> <ul id="toc-External_links-sublist" class="vector-toc-list"> </ul> </li> </ul> </div> </div> </nav> </div> </div> <div class="mw-content-container"> <main id="content" class="mw-body"> <header class="mw-body-header vector-page-titlebar"> <nav aria-label="Contents" class="vector-toc-landmark"> <div id="vector-page-titlebar-toc" class="vector-dropdown vector-page-titlebar-toc vector-button-flush-left" title="Table of Contents" > <input type="checkbox" id="vector-page-titlebar-toc-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-page-titlebar-toc" class="vector-dropdown-checkbox " aria-label="Toggle the table of contents" > <label id="vector-page-titlebar-toc-label" for="vector-page-titlebar-toc-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" ><span class="vector-icon mw-ui-icon-listBullet mw-ui-icon-wikimedia-listBullet"></span> <span class="vector-dropdown-label-text">Toggle the table of contents</span> </label> <div class="vector-dropdown-content"> <div id="vector-page-titlebar-toc-unpinned-container" class="vector-unpinned-container"> </div> </div> </div> </nav> <h1 id="firstHeading" class="firstHeading mw-first-heading"><span class="mw-page-title-main">CELT</span></h1> <div id="p-lang-btn" class="vector-dropdown mw-portlet mw-portlet-lang" > <input type="checkbox" id="p-lang-btn-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-p-lang-btn" class="vector-dropdown-checkbox mw-interlanguage-selector" aria-label="Go to an article in another language. Available in 5 languages" > <label id="p-lang-btn-label" for="p-lang-btn-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--action-progressive mw-portlet-lang-heading-5" aria-hidden="true" ><span class="vector-icon mw-ui-icon-language-progressive mw-ui-icon-wikimedia-language-progressive"></span> <span class="vector-dropdown-label-text">5 languages</span> </label> <div class="vector-dropdown-content"> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li class="interlanguage-link interwiki-de mw-list-item"><a href="https://de.wikipedia.org/wiki/Constrained-Energy_Lapped_Transform" title="Constrained-Energy Lapped Transform – German" lang="de" hreflang="de" data-title="Constrained-Energy Lapped Transform" data-language-autonym="Deutsch" data-language-local-name="German" class="interlanguage-link-target"><span>Deutsch</span></a></li><li class="interlanguage-link interwiki-fr mw-list-item"><a href="https://fr.wikipedia.org/wiki/CELT" title="CELT – French" lang="fr" hreflang="fr" data-title="CELT" data-language-autonym="Français" data-language-local-name="French" class="interlanguage-link-target"><span>Français</span></a></li><li class="interlanguage-link interwiki-ko mw-list-item"><a href="https://ko.wikipedia.org/wiki/CELT" title="CELT – Korean" lang="ko" hreflang="ko" data-title="CELT" data-language-autonym="한국어" data-language-local-name="Korean" class="interlanguage-link-target"><span>한국어</span></a></li><li class="interlanguage-link interwiki-ja mw-list-item"><a href="https://ja.wikipedia.org/wiki/CELT" title="CELT – Japanese" lang="ja" hreflang="ja" data-title="CELT" data-language-autonym="日本語" data-language-local-name="Japanese" class="interlanguage-link-target"><span>日本語</span></a></li><li class="interlanguage-link interwiki-zh mw-list-item"><a href="https://zh.wikipedia.org/wiki/CELT" title="CELT – Chinese" lang="zh" hreflang="zh" data-title="CELT" data-language-autonym="中文" data-language-local-name="Chinese" class="interlanguage-link-target"><span>中文</span></a></li> </ul> <div class="after-portlet after-portlet-lang"><span class="wb-langlinks-edit wb-langlinks-link"><a href="https://www.wikidata.org/wiki/Special:EntityPage/Q1128269#sitelinks-wikipedia" title="Edit interlanguage links" class="wbc-editpage">Edit links</a></span></div> </div> </div> </div> </header> <div class="vector-page-toolbar"> <div class="vector-page-toolbar-container"> <div id="left-navigation"> <nav aria-label="Namespaces"> <div id="p-associated-pages" class="vector-menu vector-menu-tabs mw-portlet mw-portlet-associated-pages" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="ca-nstab-main" class="selected vector-tab-noicon mw-list-item"><a href="/wiki/CELT" title="View the content page [c]" accesskey="c"><span>Article</span></a></li><li id="ca-talk" class="vector-tab-noicon mw-list-item"><a href="/wiki/Talk:CELT" rel="discussion" title="Discuss improvements to the content page [t]" accesskey="t"><span>Talk</span></a></li> </ul> </div> </div> <div id="vector-variants-dropdown" class="vector-dropdown emptyPortlet" > <input type="checkbox" id="vector-variants-dropdown-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-variants-dropdown" class="vector-dropdown-checkbox " aria-label="Change language variant" > <label id="vector-variants-dropdown-label" for="vector-variants-dropdown-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet" aria-hidden="true" ><span class="vector-dropdown-label-text">English</span> </label> <div class="vector-dropdown-content"> <div id="p-variants" class="vector-menu mw-portlet mw-portlet-variants emptyPortlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> </ul> </div> </div> </div> </div> </nav> </div> <div id="right-navigation" class="vector-collapsible"> <nav aria-label="Views"> <div id="p-views" class="vector-menu vector-menu-tabs mw-portlet mw-portlet-views" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="ca-view" class="selected vector-tab-noicon mw-list-item"><a href="/wiki/CELT"><span>Read</span></a></li><li id="ca-edit" class="vector-tab-noicon mw-list-item"><a href="/w/index.php?title=CELT&action=edit" title="Edit this page [e]" accesskey="e"><span>Edit</span></a></li><li id="ca-history" class="vector-tab-noicon mw-list-item"><a href="/w/index.php?title=CELT&action=history" title="Past revisions of this page [h]" accesskey="h"><span>View history</span></a></li> </ul> </div> </div> </nav> <nav class="vector-page-tools-landmark" aria-label="Page tools"> <div id="vector-page-tools-dropdown" class="vector-dropdown vector-page-tools-dropdown" > <input type="checkbox" id="vector-page-tools-dropdown-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-page-tools-dropdown" class="vector-dropdown-checkbox " aria-label="Tools" > <label id="vector-page-tools-dropdown-label" for="vector-page-tools-dropdown-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet" aria-hidden="true" ><span class="vector-dropdown-label-text">Tools</span> </label> <div class="vector-dropdown-content"> <div id="vector-page-tools-unpinned-container" class="vector-unpinned-container"> <div id="vector-page-tools" class="vector-page-tools vector-pinnable-element"> <div class="vector-pinnable-header vector-page-tools-pinnable-header vector-pinnable-header-unpinned" data-feature-name="page-tools-pinned" data-pinnable-element-id="vector-page-tools" data-pinned-container-id="vector-page-tools-pinned-container" data-unpinned-container-id="vector-page-tools-unpinned-container" > <div class="vector-pinnable-header-label">Tools</div> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-pin-button" data-event-name="pinnable-header.vector-page-tools.pin">move to sidebar</button> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-unpin-button" data-event-name="pinnable-header.vector-page-tools.unpin">hide</button> </div> <div id="p-cactions" class="vector-menu mw-portlet mw-portlet-cactions emptyPortlet vector-has-collapsible-items" title="More options" > <div class="vector-menu-heading"> Actions </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="ca-more-view" class="selected vector-more-collapsible-item mw-list-item"><a href="/wiki/CELT"><span>Read</span></a></li><li id="ca-more-edit" class="vector-more-collapsible-item mw-list-item"><a href="/w/index.php?title=CELT&action=edit" title="Edit this page [e]" accesskey="e"><span>Edit</span></a></li><li id="ca-more-history" class="vector-more-collapsible-item mw-list-item"><a href="/w/index.php?title=CELT&action=history"><span>View history</span></a></li> </ul> </div> </div> <div id="p-tb" class="vector-menu mw-portlet mw-portlet-tb" > <div class="vector-menu-heading"> General </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="t-whatlinkshere" class="mw-list-item"><a href="/wiki/Special:WhatLinksHere/CELT" title="List of all English Wikipedia pages containing links to this page [j]" accesskey="j"><span>What links here</span></a></li><li id="t-recentchangeslinked" class="mw-list-item"><a href="/wiki/Special:RecentChangesLinked/CELT" rel="nofollow" title="Recent changes in pages linked from this page [k]" accesskey="k"><span>Related changes</span></a></li><li id="t-upload" class="mw-list-item"><a href="//en.wikipedia.org/wiki/Wikipedia:File_Upload_Wizard" title="Upload files [u]" accesskey="u"><span>Upload file</span></a></li><li id="t-permalink" class="mw-list-item"><a href="/w/index.php?title=CELT&oldid=1221001953" title="Permanent link to this revision of this page"><span>Permanent link</span></a></li><li id="t-info" class="mw-list-item"><a href="/w/index.php?title=CELT&action=info" title="More information about this page"><span>Page information</span></a></li><li id="t-cite" class="mw-list-item"><a href="/w/index.php?title=Special:CiteThisPage&page=CELT&id=1221001953&wpFormIdentifier=titleform" title="Information on how to cite this page"><span>Cite this page</span></a></li><li id="t-urlshortener" class="mw-list-item"><a href="/w/index.php?title=Special:UrlShortener&url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FCELT"><span>Get shortened URL</span></a></li><li id="t-urlshortener-qrcode" class="mw-list-item"><a href="/w/index.php?title=Special:QrCode&url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FCELT"><span>Download QR code</span></a></li> </ul> </div> </div> <div id="p-coll-print_export" class="vector-menu mw-portlet mw-portlet-coll-print_export" > <div class="vector-menu-heading"> Print/export </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="coll-download-as-rl" class="mw-list-item"><a href="/w/index.php?title=Special:DownloadAsPdf&page=CELT&action=show-download-screen" title="Download this page as a PDF file"><span>Download as PDF</span></a></li><li id="t-print" class="mw-list-item"><a href="/w/index.php?title=CELT&printable=yes" title="Printable version of this page [p]" accesskey="p"><span>Printable version</span></a></li> </ul> </div> </div> <div id="p-wikibase-otherprojects" class="vector-menu mw-portlet mw-portlet-wikibase-otherprojects" > <div class="vector-menu-heading"> In other projects </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="t-wikibase" class="wb-otherproject-link wb-otherproject-wikibase-dataitem mw-list-item"><a href="https://www.wikidata.org/wiki/Special:EntityPage/Q1128269" title="Structured data on this page hosted by Wikidata [g]" accesskey="g"><span>Wikidata item</span></a></li> </ul> </div> </div> </div> </div> </div> </div> </nav> </div> </div> </div> <div class="vector-column-end"> <div class="vector-sticky-pinned-container"> <nav class="vector-page-tools-landmark" aria-label="Page tools"> <div id="vector-page-tools-pinned-container" class="vector-pinned-container"> </div> </nav> <nav class="vector-appearance-landmark" aria-label="Appearance"> <div id="vector-appearance-pinned-container" class="vector-pinned-container"> <div id="vector-appearance" class="vector-appearance vector-pinnable-element"> <div class="vector-pinnable-header vector-appearance-pinnable-header vector-pinnable-header-pinned" data-feature-name="appearance-pinned" data-pinnable-element-id="vector-appearance" data-pinned-container-id="vector-appearance-pinned-container" data-unpinned-container-id="vector-appearance-unpinned-container" > <div class="vector-pinnable-header-label">Appearance</div> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-pin-button" data-event-name="pinnable-header.vector-appearance.pin">move to sidebar</button> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-unpin-button" data-event-name="pinnable-header.vector-appearance.unpin">hide</button> </div> </div> </div> </nav> </div> </div> <div id="bodyContent" class="vector-body" aria-labelledby="firstHeading" data-mw-ve-target-container> <div class="vector-body-before-content"> <div class="mw-indicators"> </div> <div id="siteSub" class="noprint">From Wikipedia, the free encyclopedia</div> </div> <div id="contentSub"><div id="mw-content-subtitle"></div></div> <div id="mw-content-text" class="mw-body-content"><div class="mw-content-ltr mw-parser-output" lang="en" dir="ltr"><div class="shortdescription nomobile noexcerpt noprint searchaux" style="display:none">Audio codec and compression format</div> <style data-mw-deduplicate="TemplateStyles:r1236090951">.mw-parser-output .hatnote{font-style:italic}.mw-parser-output div.hatnote{padding-left:1.6em;margin-bottom:0.5em}.mw-parser-output .hatnote i{font-style:normal}.mw-parser-output .hatnote+link+.hatnote{margin-top:-0.5em}@media print{body.ns-0 .mw-parser-output .hatnote{display:none!important}}</style><div role="note" class="hatnote navigation-not-searchable">This article is about the audio codec. For the proposed telescope, see <a href="/wiki/California_Extremely_Large_Telescope" title="California Extremely Large Telescope">California Extremely Large Telescope</a>. For the online database of Irish texts, see <a href="/wiki/Corpus_of_Electronic_Texts" title="Corpus of Electronic Texts">Corpus of Electronic Texts</a>. For other uses, see <a href="/wiki/Celt_(disambiguation)" class="mw-disambig" title="Celt (disambiguation)">Celt (disambiguation)</a>.</div> <style data-mw-deduplicate="TemplateStyles:r1257001546">.mw-parser-output .infobox-subbox{padding:0;border:none;margin:-3px;width:auto;min-width:100%;font-size:100%;clear:none;float:none;background-color:transparent}.mw-parser-output .infobox-3cols-child{margin:auto}.mw-parser-output .infobox .navbar{font-size:100%}@media screen{html.skin-theme-clientpref-night .mw-parser-output .infobox-full-data:not(.notheme)>div:not(.notheme)[style]{background:#1f1f23!important;color:#f8f9fa}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .infobox-full-data:not(.notheme) div:not(.notheme){background:#1f1f23!important;color:#f8f9fa}}@media(min-width:640px){body.skin--responsive .mw-parser-output .infobox-table{display:table!important}body.skin--responsive .mw-parser-output .infobox-table>caption{display:table-caption!important}body.skin--responsive .mw-parser-output .infobox-table>tbody{display:table-row-group}body.skin--responsive .mw-parser-output .infobox-table tr{display:table-row!important}body.skin--responsive .mw-parser-output .infobox-table th,body.skin--responsive .mw-parser-output .infobox-table td{padding-left:inherit;padding-right:inherit}}</style><table class="infobox"><caption class="infobox-title" style="padding-bottom: 0.15em;">CELT</caption><tbody><tr><th scope="row" class="infobox-label" style="line-height: 1.2; padding-right: 0.65em;">Developed by</th><td class="infobox-data" style="line-height: 1.35;"><a href="/wiki/Xiph.Org_Foundation" title="Xiph.Org Foundation">Xiph.Org Foundation</a></td></tr><tr><th scope="row" class="infobox-label" style="line-height: 1.2; padding-right: 0.65em;">Type of format</th><td class="infobox-data" style="line-height: 1.35;">Audio</td></tr><tr><th scope="row" class="infobox-label" style="line-height: 1.2; padding-right: 0.65em;">Contained by</th><td class="infobox-data" style="line-height: 1.35;"><a href="/wiki/Ogg" title="Ogg">Ogg</a></td></tr><tr><th scope="row" class="infobox-label" style="line-height: 1.2; padding-right: 0.65em;">Extended to</th><td class="infobox-data" style="line-height: 1.35;"><a href="/wiki/Opus_(codec)" class="mw-redirect" title="Opus (codec)">Opus</a></td></tr><tr><th scope="row" class="infobox-label" style="line-height: 1.2; padding-right: 0.65em;"><a href="/wiki/International_standard" title="International standard">Standard</a></th><td class="infobox-data" style="line-height: 1.35;"><a rel="nofollow" class="external text" href="http://celt-codec.org/docs/">Documentation</a></td></tr></tbody></table> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1257001546" /><table class="infobox vevent"><caption class="infobox-title summary">libcelt</caption><tbody><tr><th scope="row" class="infobox-label" style="white-space: nowrap;"><a href="/wiki/Programmer" title="Programmer">Developer(s)</a></th><td class="infobox-data"><a href="/wiki/Xiph.org_Foundation" class="mw-redirect" title="Xiph.org Foundation">Xiph.org Foundation</a>, Jean-Marc Valin</td></tr><tr style="display: none;"><td colspan="2" class="infobox-full-data"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1257001546" /></td></tr><tr><th scope="row" class="infobox-label" style="white-space: nowrap;"><a href="/wiki/Software_release_life_cycle#Beta" title="Software release life cycle">Preview release</a></th><td class="infobox-data"><div style="margin:0px;">0.11.1 / February 15, 2011<span class="noprint">; 14 years ago</span><span style="display:none"> (<span class="bday dtstart published updated">2011-02-15</span>)</span></div></td></tr><tr style="display:none"><td colspan="2"> </td></tr><tr><th scope="row" class="infobox-label" style="white-space: nowrap;"><a href="/wiki/Software_categories#Categorization_approaches" title="Software categories">Type</a></th><td class="infobox-data"><a href="/wiki/Audio_codec" title="Audio codec">Audio codec</a>, <a href="/wiki/Reference_implementation_(computing)" class="mw-redirect" title="Reference implementation (computing)">reference implementation</a></td></tr><tr><th scope="row" class="infobox-label" style="white-space: nowrap;"><a href="/wiki/Software_license" title="Software license">License</a></th><td class="infobox-data"><a href="/wiki/BSD_licenses" title="BSD licenses">2-clause BSD</a></td></tr><tr><th scope="row" class="infobox-label" style="white-space: nowrap;">Website</th><td class="infobox-data"><span class="url"><a rel="nofollow" class="external text" href="http://opus-codec.org">opus-codec<wbr />.org</a></span></td></tr></tbody></table> <p><b>Constrained Energy Lapped Transform</b> (<b>CELT</b>) is an open, <a href="/wiki/Royalty-free" title="Royalty-free">royalty-free</a> <a href="/wiki/Lossy_compression" title="Lossy compression">lossy</a> <a href="/wiki/Audio_compression_(data)" class="mw-redirect" title="Audio compression (data)">audio compression</a> format and a <a href="/wiki/Free_software" title="Free software">free software</a> <a href="/wiki/Audio_codec" title="Audio codec">codec</a> with especially low algorithmic delay for use in <a href="/wiki/Low-latency" class="mw-redirect" title="Low-latency">low-latency</a> audio communication. The algorithms are openly documented and may be used free of <a href="/wiki/Software_patent" title="Software patent">software patent</a> restrictions. Development of the format was maintained by the <a href="/wiki/Xiph.Org_Foundation" title="Xiph.Org Foundation">Xiph.Org Foundation</a> (as part of the <a href="/wiki/Ogg" title="Ogg">Ogg</a> codec family) and later coordinated by the <a href="/wiki/Opus_(codec)" class="mw-redirect" title="Opus (codec)">Opus</a> working group of the <a href="/wiki/Internet_Engineering_Task_Force" title="Internet Engineering Task Force">Internet Engineering Task Force</a> (IETF). </p><p>CELT was meant to bridge the gap between <a href="/wiki/Vorbis" title="Vorbis">Vorbis</a> and <a href="/wiki/Speex" title="Speex">Speex</a> for applications where both high quality audio and low delay are desired.<sup id="cite_ref-celt-web_1-0" class="reference"><a href="#cite_note-celt-web-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> It is suitable for both speech and music. It borrows ideas from the <a href="/wiki/CELP" class="mw-redirect" title="CELP">CELP</a> algorithm, but avoids some of its limitations by operating in the <a href="/wiki/Frequency_domain" title="Frequency domain">frequency domain</a> exclusively.<sup id="cite_ref-celt-web_1-1" class="reference"><a href="#cite_note-celt-web-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> </p><p>The original stand-alone CELT has been merged into <a href="/wiki/Opus_(audio_format)" title="Opus (audio format)">Opus</a>. Therefore, CELT as stand-alone format is now abandoned and obsolete. Development is going on only for its hybridised form as a layer of Opus, integrated with <a href="/wiki/SILK" title="SILK">SILK</a>. This article covers the historic, stand-alone format; for the integrated form and its evolution since the integration into Opus see the article on Opus. </p> <meta property="mw:PageProp/toc" /> <div class="mw-heading mw-heading2"><h2 id="Properties">Properties</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=CELT&action=edit&section=1" title="Edit section: Properties"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>CELT's central feature is low algorithmic delay. It allows for latencies of typically 3 to 9 ms but is configurable to below 2 ms at the price of more bitrate to reach a similar audio quality.<sup id="cite_ref-presentation_2-0" class="reference"><a href="#cite_note-presentation-2"><span class="cite-bracket">[</span>2<span class="cite-bracket">]</span></a></sup> CELT supports mono and stereo audio and is applicable to both speech and music. It can use a <a href="/wiki/Sampling_rate" class="mw-redirect" title="Sampling rate">sampling rate</a> from 32 kHz to 48 kHz and above and an adaptive bitrate from 24 kbit/s to 128 kbit/s per channel and above.<sup id="cite_ref-presentation_2-1" class="reference"><a href="#cite_note-presentation-2"><span class="cite-bracket">[</span>2<span class="cite-bracket">]</span></a></sup> </p><p>There are no known <a href="/wiki/Intellectual_property" title="Intellectual property">intellectual property</a> issues pertaining to the CELT algorithm, and its reference implementation is published under a permissive open-source license (the <a href="/wiki/BSD_licenses" title="BSD licenses">2-clause BSD</a>).<sup id="cite_ref-celt-web_1-2" class="reference"><a href="#cite_note-celt-web-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-ietf-codec_3-0" class="reference"><a href="#cite_note-ietf-codec-3"><span class="cite-bracket">[</span>3<span class="cite-bracket">]</span></a></sup> </p><p>Like <a href="/wiki/Vorbis" title="Vorbis">Vorbis</a>, CELT is a fullband (entire human <a href="/wiki/Hearing_range" title="Hearing range">hearing range</a>) general-purpose codec, i.e. not specialized for special types of audio signals and therefore different from its sibling project <a href="/wiki/Speex" title="Speex">Speex</a>. The format enables for <a href="/wiki/Transparency_(data_compression)" title="Transparency (data compression)">transparent</a> results at high bitrates, as well as very decent quality at lower bitrates. All in all, the compression capabilities are said to be significantly superior to those of <a href="/wiki/MP3" title="MP3">MP3</a>, and as another useful feature for realtime applications like telephony, CELT's audio quality at lower bitrates are even on par with <a href="/wiki/High-Efficiency_Advanced_Audio_Coding" title="High-Efficiency Advanced Audio Coding">HE-AAC</a>v1, thanks to the band folding.<sup id="cite_ref-AutoV5-2_4-0" class="reference"><a href="#cite_note-AutoV5-2-4"><span class="cite-bracket">[</span>4<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-monty_5-0" class="reference"><a href="#cite_note-monty-5"><span class="cite-bracket">[</span>5<span class="cite-bracket">]</span></a></sup> In comparative double-blind listening tests it proved to be noticeably superior to HE-AACv1 at ~64 kbit/s.<sup id="cite_ref-AutoV5-3_6-0" class="reference"><a href="#cite_note-AutoV5-3-6"><span class="cite-bracket">[</span>6<span class="cite-bracket">]</span></a></sup> </p><p>It has a comparably low computational complexity that resembles that of the low-delay variant of <a href="/wiki/Advanced_Audio_Coding" title="Advanced Audio Coding">AAC</a> (AAC-LD) and stays significantly below the complexity of Vorbis.<sup id="cite_ref-TASL_7-0" class="reference"><a href="#cite_note-TASL-7"><span class="cite-bracket">[</span>7<span class="cite-bracket">]</span></a></sup> </p><p>It enables for <a href="/wiki/Constant_bitrate" title="Constant bitrate">constant</a> and <a href="/wiki/Variable_bitrate" title="Variable bitrate">variable</a> bitrate. If the signal disappears into the noise floor in speech pauses and similar cases, the transmission can be limited to signal the output of <a href="/wiki/Comfort_noise" title="Comfort noise">comfort noise</a> to the decoder. Most settings of the naturally streaming-enabled format can be changed on the fly without interrupting transmission. </p><p>The format is robust to transmission errors. Loss of whole packets as well as bit errors can be masked with a steady degradation of audio quality (<a href="/wiki/Packet_loss_concealment" title="Packet loss concealment">packet loss concealment</a>, PLC). </p> <div class="mw-heading mw-heading2"><h2 id="Technology">Technology</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=CELT&action=edit&section=2" title="Edit section: Technology"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <figure class="mw-default-size mw-halign-center" typeof="mw:File/Thumb"><a href="/wiki/File:CELT-codec-block-diagram-simple-en.svg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/9/93/CELT-codec-block-diagram-simple-en.svg/960px-CELT-codec-block-diagram-simple-en.svg.png" decoding="async" width="880" height="113" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/9/93/CELT-codec-block-diagram-simple-en.svg/1320px-CELT-codec-block-diagram-simple-en.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/9/93/CELT-codec-block-diagram-simple-en.svg/1760px-CELT-codec-block-diagram-simple-en.svg.png 2x" data-file-width="1050" data-file-height="135" /></a><figcaption>block diagram of the codec</figcaption></figure> <p>CELT is a <a href="/wiki/Transform_coding" title="Transform coding">transform codec</a> based on the <a href="/wiki/Modified_discrete_cosine_transform" title="Modified discrete cosine transform">modified discrete cosine transform</a> (MDCT) and concepts from <a href="/wiki/Code-excited_linear_prediction" title="Code-excited linear prediction">CELP</a> (with a code book for excitation, but in the frequency domain). </p><p>The initial <a href="/wiki/Pulse-code_modulation" title="Pulse-code modulation">PCM-coded</a> signal is handled in relatively small, overlapping blocks for the MDCT (<a href="/wiki/Window_function" title="Window function">window function</a>) and transformed to frequency coefficients. Choosing an especially short block size on the one hand enables for a low latency, but also leads to poor frequency resolution that has to be compensated. For a further reduction of the algorithmic delay to the expense of a minor sacrifice in audio quality, the by nature 50% of overlap between the blocks is practically cut down to half by silencing the signal during one eight at both ends of a block, respectively.<sup id="cite_ref-presentation_2-2" class="reference"><a href="#cite_note-presentation-2"><span class="cite-bracket">[</span>2<span class="cite-bracket">]</span></a></sup> </p><p>The coefficients are grouped to resemble the <a href="/wiki/Critical_band" title="Critical band">critical bands</a> of the human auditory system. The entire amount of energy of each group is analysed and the values <a href="/wiki/Quantization_(signal_processing)" title="Quantization (signal processing)">quantised</a> for <a href="/wiki/Data_reduction" title="Data reduction">data reduction</a> and compressed through prediction by only transmitting the difference to the predicted values (<a href="/wiki/Delta_encoding" title="Delta encoding">delta encoding</a>). </p><p>The (unquantised) band energy values are removed from the raw DCT coefficients (normalisation). The coefficients of the resulting residual signal (so-called “band shape”) are coded by <a href="/wiki/Pyramid_vector_quantization" title="Pyramid vector quantization">Pyramid Vector Quantisation</a> (PVQ, a spherical <a href="/wiki/Vector_quantisation" class="mw-redirect" title="Vector quantisation">vector quantisation</a>).<sup id="cite_ref-AutoV5-4_8-0" class="reference"><a href="#cite_note-AutoV5-4-8"><span class="cite-bracket">[</span>8<span class="cite-bracket">]</span></a></sup> This encoding leads to code words of fixed (predictable) length, which in turn enables for robustness against bit errors and leaves no need for <a href="/wiki/Entropy_encoding" class="mw-redirect" title="Entropy encoding">entropy encoding</a>.<sup id="cite_ref-monty_5-1" class="reference"><a href="#cite_note-monty-5"><span class="cite-bracket">[</span>5<span class="cite-bracket">]</span></a></sup> Finally, all output of the encoder are coded to one bitstream by a <a href="/wiki/Range_encoding" class="mw-redirect" title="Range encoding">range encoder</a>.<sup id="cite_ref-AutoV5-5_9-0" class="reference"><a href="#cite_note-AutoV5-5-9"><span class="cite-bracket">[</span>9<span class="cite-bracket">]</span></a></sup> In connection with the PVQ, CELT uses a technique known as band folding, which delivers a similar effect to <a href="/wiki/Spectral_band_replication" title="Spectral band replication">spectral band replication</a> (SBR) by reusing coefficients of lower bands for higher ones, but has much less impact on the algorithmic delay and computational complexity than the SBR. This works against <a href="/wiki/Compression_artifact" title="Compression artifact">“birdie” artifacts</a> by preserving more richness in the appropriate frequency bands. </p><p>The decoder unpacks the individual components from the range coded bitstream, multiplies the band energy to the band shape coefficients and transforms them back (via iMDCT) to PCM data. The individual blocks are rejoined using weighted <a href="/wiki/Overlap-add_method" class="mw-redirect" title="Overlap-add method">overlap-add</a> (WOLA). Many parameters are not explicitly coded, but instead reconstructed by using the same functions as the encoder. </p><p>For the <a href="/wiki/Joint_encoding" title="Joint encoding">channel coupling</a> CELT may use <a href="/wiki/Joint_encoding#M/S_stereo_coding" title="Joint encoding">M/S stereo</a> or <a href="/wiki/Joint_encoding#Intensity_stereo_coding" title="Joint encoding">intensity stereo</a>. Blocks can be described independent from adjacent frames (<a href="/wiki/Intra-frame" class="mw-redirect" title="Intra-frame">Intra-frame</a>); for example to enable a decoder to jump into a running stream. With transform codecs so-called pre-echo artifacts can get audible, because the quantisation error of sharp, energy-heavy sounds (<a href="/wiki/Transient_(acoustics)" title="Transient (acoustics)">transients</a>) can spread over the entire DCT block and the transient doesn't mask them backward in time as well as forward. With CELT each block can be further divided to thwart such artifacts. </p> <div class="mw-heading mw-heading2"><h2 id="History">History</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=CELT&action=edit&section=3" title="Edit section: History"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>First work on plans and drafts for a Vorbis successor was done in 2005 at <a href="/wiki/Xiph.org_Foundation" class="mw-redirect" title="Xiph.org Foundation">Xiph.org</a> as part of the Ghost project (initially talked about as “Vorbis II”). This discussion together with Vorbis creator <a href="/wiki/Christopher_Montgomery" class="mw-redirect" title="Christopher Montgomery">Christopher Montgomery</a> led to Jean-Marc Valin′s interest in a particularly low-latency codec. Valin has worked on CELT since 2007.<sup id="cite_ref-monty_5-2" class="reference"><a href="#cite_note-monty-5"><span class="cite-bracket">[</span>5<span class="cite-bracket">]</span></a></sup> In December 2007, the first draft version of libcelt was published as version 0.0.1, initially named “Code-Excited Lapped Transform”.<sup id="cite_ref-AutoV5-6_10-0" class="reference"><a href="#cite_note-AutoV5-6-10"><span class="cite-bracket">[</span>10<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-AutoV5-1_11-0" class="reference"><a href="#cite_note-AutoV5-1-11"><span class="cite-bracket">[</span>11<span class="cite-bracket">]</span></a></sup> CELT was established as an <a href="/wiki/Internet_Engineering_Task_Force" title="Internet Engineering Task Force">IETF</a> technology in July 2009<sup id="cite_ref-ietf-codec_3-1" class="reference"><a href="#cite_note-ietf-codec-3"><span class="cite-bracket">[</span>3<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-AutoV5-7_12-0" class="reference"><a href="#cite_note-AutoV5-7-12"><span class="cite-bracket">[</span>12<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-AutoV5-8_13-0" class="reference"><a href="#cite_note-AutoV5-8-13"><span class="cite-bracket">[</span>13<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-AutoV5-9_14-0" class="reference"><a href="#cite_note-AutoV5-9-14"><span class="cite-bracket">[</span>14<span class="cite-bracket">]</span></a></sup> under the "ietfcodec" working group. In May 2009, a draft of <i><a href="/wiki/Real-time_Transport_Protocol" title="Real-time Transport Protocol">RTP</a> payload format for the CELT Codec</i> was published.<sup id="cite_ref-AutoV5-10_15-0" class="reference"><a href="#cite_note-AutoV5-10-15"><span class="cite-bracket">[</span>15<span class="cite-bracket">]</span></a></sup> </p><p>In version 0.9, the pitch prediction operating in the frequency domain used until then was replaced by a less complex solution with a pre- and postfilter pair in time domain,<sup id="cite_ref-AutoV5-11_16-0" class="reference"><a href="#cite_note-AutoV5-11-16"><span class="cite-bracket">[</span>16<span class="cite-bracket">]</span></a></sup> which was contributed by Raymond Chen of <a href="/wiki/Broadcom" title="Broadcom">Broadcom</a>.<sup id="cite_ref-monty_5-3" class="reference"><a href="#cite_note-monty-5"><span class="cite-bracket">[</span>5<span class="cite-bracket">]</span></a></sup> </p><p>With CELT 0.11 from February 4, 2011 the format was tentatively frozen (“soft freeze”) – reserving the possibility of unexpectedly necessary last changes. </p><p>Shortly after the advent of the CELT/<a href="/wiki/SILK" title="SILK">SILK</a> hybrid codec <a href="/wiki/Opus_(codec)" class="mw-redirect" title="Opus (codec)">Opus</a> (formerly known as Harmony), the development of CELT as a separate project was halted, instead living on the basis of Opus,<sup id="cite_ref-AutoV5-12_17-0" class="reference"><a href="#cite_note-AutoV5-12-17"><span class="cite-bracket">[</span>17<span class="cite-bracket">]</span></a></sup> which aims to treat the lower part of the spectral range in the time domain with <a href="/wiki/Linear_prediction" title="Linear prediction">linear prediction</a> (SILK) and the higher part in the frequency domain with the <a href="/wiki/Modified_discrete_cosine_transform" title="Modified discrete cosine transform">MDCT</a>. The draft for Opus has been registered at the IETF since September 2010. </p> <div class="mw-heading mw-heading2"><h2 id="Software">Software</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=CELT&action=edit&section=4" title="Edit section: Software"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The <a href="/wiki/Library_(computing)" title="Library (computing)">software library</a> <b>libcelt</b> serves as the <a href="/wiki/Reference_implementation" title="Reference implementation">reference implementation</a> for CELT, written in <a href="/wiki/C_(programming_language)" title="C (programming language)">C</a> and published as <a href="/wiki/Free_software" title="Free software">free software</a> under Xiph's own 3-clause BSD-ish license. </p><p>Despite the format not being finally frozen, it was being used in many <a href="/wiki/Voice_over_IP" title="Voice over IP">VoIP</a> applications such as <a href="/wiki/Ekiga" title="Ekiga">Ekiga</a><sup id="cite_ref-ekiga_18-0" class="reference"><a href="#cite_note-ekiga-18"><span class="cite-bracket">[</span>18<span class="cite-bracket">]</span></a></sup> and <a href="/wiki/FreeSWITCH" title="FreeSWITCH">FreeSWITCH</a>,<sup id="cite_ref-AutoV5-14_19-0" class="reference"><a href="#cite_note-AutoV5-14-19"><span class="cite-bracket">[</span>19<span class="cite-bracket">]</span></a></sup> which switched to CELT upon entering soft-freeze in January 2009, as well as <a href="/wiki/Mumble_(software)" title="Mumble (software)">Mumble</a>, <a href="/wiki/TeamSpeak" title="TeamSpeak">TeamSpeak</a> and other<sup id="cite_ref-software_20-0" class="reference"><a href="#cite_note-software-20"><span class="cite-bracket">[</span>20<span class="cite-bracket">]</span></a></sup> software. In April 2011, support for CELT was included in <a href="/wiki/FFmpeg" title="FFmpeg">FFmpeg</a>.<sup id="cite_ref-ffmpeg1_21-0" class="reference"><a href="#cite_note-ffmpeg1-21"><span class="cite-bracket">[</span>21<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-ffmpeg2_22-0" class="reference"><a href="#cite_note-ffmpeg2-22"><span class="cite-bracket">[</span>22<span class="cite-bracket">]</span></a></sup> </p><p>CELT is also supported or used by:<sup id="cite_ref-software_20-1" class="reference"><a href="#cite_note-software-20"><span class="cite-bracket">[</span>20<span class="cite-bracket">]</span></a></sup> </p> <ul><li><a href="/wiki/GStreamer" title="GStreamer">GStreamer</a></li> <li><a href="/wiki/JACK_Audio_Connection_Kit" title="JACK Audio Connection Kit">jack-audio-connection-kit</a> (netjack)</li> <li><a href="/wiki/Mumble_(software)" title="Mumble (software)">Mumble</a> (starting with version 1.2)</li> <li><a href="/wiki/SFLphone" class="mw-redirect" title="SFLphone">SFLphone</a></li> <li><a href="/wiki/TeamSpeak" title="TeamSpeak">TeamSpeak</a> 3</li> <li><a href="/wiki/SPICE_(protocol)" class="mw-redirect" title="SPICE (protocol)">SPICE</a></li> <li><a href="/wiki/Dota_2" title="Dota 2">Dota 2</a><sup id="cite_ref-dota2_23-0" class="reference"><a href="#cite_note-dota2-23"><span class="cite-bracket">[</span>23<span class="cite-bracket">]</span></a></sup></li> <li><a href="/wiki/Counter_Strike:_Global_Offensive" class="mw-redirect" title="Counter Strike: Global Offensive">Counter Strike: Global Offensive</a></li> <li><a href="/wiki/Team_Fortress_2" title="Team Fortress 2">Team Fortress 2</a><sup id="cite_ref-tf2_24-0" class="reference"><a href="#cite_note-tf2-24"><span class="cite-bracket">[</span>24<span class="cite-bracket">]</span></a></sup></li></ul> <div class="mw-heading mw-heading2"><h2 id="See_also">See also</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=CELT&action=edit&section=5" title="Edit section: See also"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles:r1266661725">.mw-parser-output .portalbox{padding:0;margin:0.5em 0;display:table;box-sizing:border-box;max-width:175px;list-style:none}.mw-parser-output .portalborder{border:1px solid var(--border-color-base,#a2a9b1);padding:0.1em;background:var(--background-color-neutral-subtle,#f8f9fa)}.mw-parser-output .portalbox-entry{display:table-row;font-size:85%;line-height:110%;height:1.9em;font-style:italic;font-weight:bold}.mw-parser-output .portalbox-image{display:table-cell;padding:0.2em;vertical-align:middle;text-align:center}.mw-parser-output .portalbox-link{display:table-cell;padding:0.2em 0.2em 0.2em 0.3em;vertical-align:middle}@media(min-width:720px){.mw-parser-output .portalleft{margin:0.5em 1em 0.5em 0}.mw-parser-output .portalright{clear:right;float:right;margin:0.5em 0 0.5em 1em}}</style><ul role="navigation" aria-label="Portals" class="noprint portalbox portalborder portalright"> <li class="portalbox-entry"><span class="portalbox-image"><span class="noviewer" typeof="mw:File"><span><img alt="" src="//upload.wikimedia.org/wikipedia/commons/thumb/3/31/Free_and_open-source_software_logo_%282009%29.svg/28px-Free_and_open-source_software_logo_%282009%29.svg.png" decoding="async" width="28" height="28" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/3/31/Free_and_open-source_software_logo_%282009%29.svg/42px-Free_and_open-source_software_logo_%282009%29.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/3/31/Free_and_open-source_software_logo_%282009%29.svg/56px-Free_and_open-source_software_logo_%282009%29.svg.png 2x" data-file-width="512" data-file-height="512" /></span></span></span><span class="portalbox-link"><a href="/wiki/Portal:Free_and_open-source_software" title="Portal:Free and open-source software">Free and open-source software portal</a></span></li></ul> <ul><li><a href="/wiki/Comparison_of_audio_coding_formats" title="Comparison of audio coding formats">Comparison of audio coding formats</a></li> <li><a href="/wiki/Opus_(audio_format)" title="Opus (audio format)">Opus (audio format)</a> - successor of CELT</li></ul> <div class="mw-heading mw-heading2"><h2 id="References">References</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=CELT&action=edit&section=6" title="Edit section: References"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles:r1239543626">.mw-parser-output .reflist{margin-bottom:0.5em;list-style-type:decimal}@media screen{.mw-parser-output .reflist{font-size:90%}}.mw-parser-output .reflist .references{font-size:100%;margin-bottom:0;list-style-type:inherit}.mw-parser-output .reflist-columns-2{column-width:30em}.mw-parser-output .reflist-columns-3{column-width:25em}.mw-parser-output .reflist-columns{margin-top:0.3em}.mw-parser-output .reflist-columns ol{margin-top:0}.mw-parser-output .reflist-columns li{page-break-inside:avoid;break-inside:avoid-column}.mw-parser-output .reflist-upper-alpha{list-style-type:upper-alpha}.mw-parser-output .reflist-upper-roman{list-style-type:upper-roman}.mw-parser-output .reflist-lower-alpha{list-style-type:lower-alpha}.mw-parser-output .reflist-lower-greek{list-style-type:lower-greek}.mw-parser-output .reflist-lower-roman{list-style-type:lower-roman}</style><div class="reflist reflist-columns references-column-width" style="column-width: 30em;"> <ol class="references"> <li id="cite_note-celt-web-1"><span class="mw-cite-backlink">^ <a href="#cite_ref-celt-web_1-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-celt-web_1-1"><sup><i><b>b</b></i></sup></a> <a href="#cite_ref-celt-web_1-2"><sup><i><b>c</b></i></sup></a></span> <span class="reference-text">Xiph.Org <a rel="nofollow" class="external text" href="http://www.celt-codec.org/">The CELT ultra low-delay audio codec - home page</a> <a rel="nofollow" class="external text" href="https://web.archive.org/web/20180831004441/http://celt-codec.org/">Archived</a> 2018-08-31 at the <a href="/wiki/Wayback_Machine" title="Wayback Machine">Wayback Machine</a>, Retrieved 2009-09-01</span> </li> <li id="cite_note-presentation-2"><span class="mw-cite-backlink">^ <a href="#cite_ref-presentation_2-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-presentation_2-1"><sup><i><b>b</b></i></sup></a> <a href="#cite_ref-presentation_2-2"><sup><i><b>c</b></i></sup></a></span> <span class="reference-text"><a rel="nofollow" class="external text" href="http://people.xiph.org/~greg/video/linux_conf_au_CELT_2.ogv">Presentation of the codec</a> <a rel="nofollow" class="external text" href="https://web.archive.org/web/20110807182250/http://people.xiph.org/~greg/video/linux_conf_au_CELT_2.ogv">Archived</a> 2011-08-07 at the <a href="/wiki/Wayback_Machine" title="Wayback Machine">Wayback Machine</a> by Timothy B. Terriberry (65 minutes of video in ~100 MiB OggTheora+Vorbis, see also <a rel="nofollow" class="external text" href="http://www.celt-codec.org/presentations/misc/lca-celt.pdf">presentation slides</a> <a rel="nofollow" class="external text" href="https://web.archive.org/web/20110810032741/http://celt-codec.org/presentations/misc/lca-celt.pdf">Archived</a> 2011-08-10 at the <a href="/wiki/Wayback_Machine" title="Wayback Machine">Wayback Machine</a> in PDF, ~2,3 MiB)</span> </li> <li id="cite_note-ietf-codec-3"><span class="mw-cite-backlink">^ <a href="#cite_ref-ietf-codec_3-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-ietf-codec_3-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text"><style data-mw-deduplicate="TemplateStyles:r1238218222">.mw-parser-output cite.citation{font-style:inherit;word-wrap:break-word}.mw-parser-output .citation q{quotes:"\"""\"""'""'"}.mw-parser-output .citation:target{background-color:rgba(0,127,255,0.133)}.mw-parser-output .id-lock-free.id-lock-free a{background:url("//upload.wikimedia.org/wikipedia/commons/6/65/Lock-green.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-limited.id-lock-limited a,.mw-parser-output .id-lock-registration.id-lock-registration a{background:url("//upload.wikimedia.org/wikipedia/commons/d/d6/Lock-gray-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-subscription.id-lock-subscription a{background:url("//upload.wikimedia.org/wikipedia/commons/a/aa/Lock-red-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .cs1-ws-icon a{background:url("//upload.wikimedia.org/wikipedia/commons/4/4c/Wikisource-logo.svg")right 0.1em center/12px no-repeat}body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-free a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-limited a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-registration a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-subscription a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .cs1-ws-icon a{background-size:contain;padding:0 1em 0 0}.mw-parser-output .cs1-code{color:inherit;background:inherit;border:none;padding:inherit}.mw-parser-output .cs1-hidden-error{display:none;color:var(--color-error,#d33)}.mw-parser-output .cs1-visible-error{color:var(--color-error,#d33)}.mw-parser-output .cs1-maint{display:none;color:#085;margin-left:0.3em}.mw-parser-output .cs1-kern-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right{padding-right:0.2em}.mw-parser-output .citation .mw-selflink{font-weight:inherit}@media screen{.mw-parser-output .cs1-format{font-size:95%}html.skin-theme-clientpref-night .mw-parser-output .cs1-maint{color:#18911f}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .cs1-maint{color:#18911f}}</style><cite id="CITEREFValinTerriberryMaxwellMontgomery2010" class="citation web cs1">Valin, Jean-Marc; Terriberry, Timothy B.; Maxwell, Greg; Montgomery, Christopher (8 July 2010). <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/drafts/draft-valin-celt-codec/">"Constrained-Energy Lapped Transform (CELT) Codec"</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Constrained-Energy+Lapped+Transform+%28CELT%29+Codec&rft.date=2010-07-08&rft.aulast=Valin&rft.aufirst=Jean-Marc&rft.au=Terriberry%2C+Timothy+B.&rft.au=Maxwell%2C+Greg&rft.au=Montgomery%2C+Christopher&rft_id=https%3A%2F%2Fdatatracker.ietf.org%2Fdrafts%2Fdraft-valin-celt-codec%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3ACELT" class="Z3988"></span></span> </li> <li id="cite_note-AutoV5-2-4"><span class="mw-cite-backlink"><b><a href="#cite_ref-AutoV5-2_4-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite id="CITEREFFiona_Glaser2010" class="citation web cs1">Fiona Glaser (2010-11-18). <a rel="nofollow" class="external text" href="http://lists.mplayerhq.hu/pipermail/ffmpeg-devel/2010-November/098196.html">"Important: upcoming CELT bitstream freeze!"</a>. <i>ffmpeg-devel.mplayerhq.hu - FFmpeg development discussions and patches mailing list</i>. mplayerhq.hu<span class="reference-accessdate">. Retrieved <span class="nowrap">2012-06-11</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=ffmpeg-devel.mplayerhq.hu+-+FFmpeg+development+discussions+and+patches+mailing+list&rft.atitle=Important%3A+upcoming+CELT+bitstream+freeze%21&rft.date=2010-11-18&rft.au=Fiona+Glaser&rft_id=http%3A%2F%2Flists.mplayerhq.hu%2Fpipermail%2Fffmpeg-devel%2F2010-November%2F098196.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3ACELT" class="Z3988"></span></span> </li> <li id="cite_note-monty-5"><span class="mw-cite-backlink">^ <a href="#cite_ref-monty_5-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-monty_5-1"><sup><i><b>b</b></i></sup></a> <a href="#cite_ref-monty_5-2"><sup><i><b>c</b></i></sup></a> <a href="#cite_ref-monty_5-3"><sup><i><b>d</b></i></sup></a></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite id="CITEREFChristopher_Montgomery2010" class="citation web cs1"><a href="/wiki/Chris_Montgomery" title="Chris Montgomery">Christopher Montgomery</a> (2010-12-23). <a rel="nofollow" class="external text" href="https://web.archive.org/web/20130823153533/http://people.xiph.org/~xiphmont/demo/celt/demo.html">"next generation audio: CELT update 20101223"</a>. <i>Monty's demo pages</i>. Xiph.Org. Archived from <a rel="nofollow" class="external text" href="http://people.xiph.org/~xiphmont/demo/celt/demo.html">the original</a> on 2013-08-23<span class="reference-accessdate">. Retrieved <span class="nowrap">2012-06-11</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=Monty%27s+demo+pages&rft.atitle=next+generation+audio%3A+CELT+update+20101223&rft.date=2010-12-23&rft.au=Christopher+Montgomery&rft_id=http%3A%2F%2Fpeople.xiph.org%2F~xiphmont%2Fdemo%2Fcelt%2Fdemo.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3ACELT" class="Z3988"></span></span> </li> <li id="cite_note-AutoV5-3-6"><span class="mw-cite-backlink"><b><a href="#cite_ref-AutoV5-3_6-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite id="CITEREFDirk_Bösel2011" class="citation web cs1 cs1-prop-foreign-lang-source">Dirk Bösel (2011-04-18). <a rel="nofollow" class="external text" href="http://mpex.net/news/archiv/01153.html">"CELT beeindruckt beim 64 kb/s Multiformat Hörtest (2011)"</a>. <i>MPeX.net</i> (in German). MPeX.net GmbH<span class="reference-accessdate">. Retrieved <span class="nowrap">2011-04-25</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=MPeX.net&rft.atitle=CELT+beeindruckt+beim+64+kb%2Fs+Multiformat+H%C3%B6rtest+%282011%29&rft.date=2011-04-18&rft.au=Dirk+B%C3%B6sel&rft_id=http%3A%2F%2Fmpex.net%2Fnews%2Farchiv%2F01153.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3ACELT" class="Z3988"></span></span> </li> <li id="cite_note-TASL-7"><span class="mw-cite-backlink"><b><a href="#cite_ref-TASL_7-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite id="CITEREFValinTerriberryMontgomeryMaxwell2009" class="citation cs2">Valin, Jean-Marc; Terriberry, Timothy B.; <a href="/wiki/Chris_Montgomery" title="Chris Montgomery">Montgomery, Christopher</a>; Maxwell, Gregory (17 April 2009), <a rel="nofollow" class="external text" href="http://people.xiph.org/~jm/papers/celt_tasl.pdf">"A High-Quality Speech and Audio Codec With Less Than 10 ms Delay"</a> <span class="cs1-format">(PDF)</span>, <i>IEEE Transactions on Audio, Speech, and Language Processing</i>, vol. 18, no. 1, IEEE Signal Processing Society<span class="reference-accessdate">, retrieved <span class="nowrap">2011-02-16</span></span></cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=IEEE+Transactions+on+Audio%2C+Speech%2C+and+Language+Processing&rft.atitle=A+High-Quality+Speech+and+Audio+Codec+With+Less+Than+10+ms+Delay&rft.volume=18&rft.issue=1&rft.date=2009-04-17&rft.aulast=Valin&rft.aufirst=Jean-Marc&rft.au=Terriberry%2C+Timothy+B.&rft.au=Montgomery%2C+Christopher&rft.au=Maxwell%2C+Gregory&rft_id=http%3A%2F%2Fpeople.xiph.org%2F~jm%2Fpapers%2Fcelt_tasl.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3ACELT" class="Z3988"></span></span> </li> <li id="cite_note-AutoV5-4-8"><span class="mw-cite-backlink"><b><a href="#cite_ref-AutoV5-4_8-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite id="CITEREFFischer1986" class="citation cs2">Fischer, Thomas R. (July 1986), "A pyramid vector quantizer", <i>IEEE Transactions on Information Theory</i>, vol. 32, no. 4, pp. <span class="nowrap">568–</span>583, <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1109%2FTIT.1986.1057198">10.1109/TIT.1986.1057198</a></cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=IEEE+Transactions+on+Information+Theory&rft.atitle=A+pyramid+vector+quantizer&rft.volume=32&rft.issue=4&rft.pages=%3Cspan+class%3D%22nowrap%22%3E568-%3C%2Fspan%3E583&rft.date=1986-07&rft_id=info%3Adoi%2F10.1109%2FTIT.1986.1057198&rft.aulast=Fischer&rft.aufirst=Thomas+R.&rfr_id=info%3Asid%2Fen.wikipedia.org%3ACELT" class="Z3988"></span></span> </li> <li id="cite_note-AutoV5-5-9"><span class="mw-cite-backlink"><b><a href="#cite_ref-AutoV5-5_9-0">^</a></b></span> <span class="reference-text"><a rel="nofollow" class="external text" href="http://tools.ietf.org/html/draft-valin-celt-codec-02">second version of the draft of the specification</a></span> </li> <li id="cite_note-AutoV5-6-10"><span class="mw-cite-backlink"><b><a href="#cite_ref-AutoV5-6_10-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite id="CITEREFJean-Marc_Valin2007" class="citation web cs1">Jean-Marc Valin (2007-12-09). <a rel="nofollow" class="external text" href="http://www.hydrogenaud.io/forums/?showtopic=59581#post-534616">"Experimental release of Ghost/CELT 0.0.1"</a>. <i>Hydrogenaudio Forums</i><span class="reference-accessdate">. Retrieved <span class="nowrap">2012-06-11</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=Hydrogenaudio+Forums&rft.atitle=Experimental+release+of+Ghost%2FCELT+0.0.1&rft.date=2007-12-09&rft.au=Jean-Marc+Valin&rft_id=http%3A%2F%2Fwww.hydrogenaud.io%2Fforums%2F%3Fshowtopic%3D59581%23post-534616&rfr_id=info%3Asid%2Fen.wikipedia.org%3ACELT" class="Z3988"></span></span> </li> <li id="cite_note-AutoV5-1-11"><span class="mw-cite-backlink"><b><a href="#cite_ref-AutoV5-1_11-0">^</a></b></span> <span class="reference-text">Xiph.Org (2007-12-08) <a rel="nofollow" class="external text" href="http://downloads.xiph.org/releases/celt/">CELT releases – celt-0.0.1.tar.gz</a>, Retrieved 2009-09-01</span> </li> <li id="cite_note-AutoV5-7-12"><span class="mw-cite-backlink"><b><a href="#cite_ref-AutoV5-7_12-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite id="CITEREFMonika_Ermert2009" class="citation web cs1">Monika Ermert (2009-11-13). <a rel="nofollow" class="external text" href="http://www.heise.de/-858956.html">"IETF kümmert sich um lizenzfreien Audiocodec"</a>. <i>heise online</i><span class="reference-accessdate">. Retrieved <span class="nowrap">2011-02-12</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=heise+online&rft.atitle=IETF+k%C3%BCmmert+sich+um+lizenzfreien+Audiocodec&rft.date=2009-11-13&rft.au=Monika+Ermert&rft_id=http%3A%2F%2Fwww.heise.de%2F-858956.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3ACELT" class="Z3988"></span></span> </li> <li id="cite_note-AutoV5-8-13"><span class="mw-cite-backlink"><b><a href="#cite_ref-AutoV5-8_13-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite id="CITEREFValinTerriberryMaxwellMontgomery2010" class="citation journal cs1">Valin, Jean-Marc; Terriberry, Timothy; Maxwell, Gregory; Montgomery, Christopher (8 July 2010). <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/draft-valin-celt-codec-01">"Constrained-Energy Lapped Transform (CELT) Codec"</a>. <i>IETF Datatracker</i>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=IETF+Datatracker&rft.atitle=Constrained-Energy+Lapped+Transform+%28CELT%29+Codec&rft.date=2010-07-08&rft.aulast=Valin&rft.aufirst=Jean-Marc&rft.au=Terriberry%2C+Timothy&rft.au=Maxwell%2C+Gregory&rft.au=Montgomery%2C+Christopher&rft_id=https%3A%2F%2Fdatatracker.ietf.org%2Fdoc%2Fhtml%2Fdraft-valin-celt-codec-01&rfr_id=info%3Asid%2Fen.wikipedia.org%3ACELT" class="Z3988"></span></span> </li> <li id="cite_note-AutoV5-9-14"><span class="mw-cite-backlink"><b><a href="#cite_ref-AutoV5-9_14-0">^</a></b></span> <span class="reference-text">IETF - AVT Working Group (2009-07-04) <a rel="nofollow" class="external text" href="http://tools.ietf.org/html/draft-valin-celt-codec-00">Constrained-Energy Lapped Transform (CELT) Codec</a>, Retrieved 2009-09-01</span> </li> <li id="cite_note-AutoV5-10-15"><span class="mw-cite-backlink"><b><a href="#cite_ref-AutoV5-10_15-0">^</a></b></span> <span class="reference-text">IETF - AVT Working Group (2009-05-08) <a rel="nofollow" class="external text" href="http://tools.ietf.org/html/draft-valin-celt-rtp-profile-00">RTP Payload Format for the CELT Codec</a>, Retrieved 2009-09-01</span> </li> <li id="cite_note-AutoV5-11-16"><span class="mw-cite-backlink"><b><a href="#cite_ref-AutoV5-11_16-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite id="CITEREFJean-Marc_Valin2011" class="citation web cs1">Jean-Marc Valin (2011-02-15). <a rel="nofollow" class="external text" href="https://web.archive.org/web/20120402203648/http://lists.xiph.org/pipermail/celt-dev/2011-February/000580.html">"CELT decoder complexity"</a>. <i>CELT-dev</i>. Xiph.Org. Archived from <a rel="nofollow" class="external text" href="http://lists.xiph.org/pipermail/celt-dev/2011-February/000580.html">the original</a> on 2012-04-02<span class="reference-accessdate">. Retrieved <span class="nowrap">2012-06-11</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=CELT-dev&rft.atitle=CELT+decoder+complexity&rft.date=2011-02-15&rft.au=Jean-Marc+Valin&rft_id=http%3A%2F%2Flists.xiph.org%2Fpipermail%2Fcelt-dev%2F2011-February%2F000580.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3ACELT" class="Z3988"></span></span> </li> <li id="cite_note-AutoV5-12-17"><span class="mw-cite-backlink"><b><a href="#cite_ref-AutoV5-12_17-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite id="CITEREFJean-Marc_Valin,_Koen_Vos2010" class="citation web cs1">Jean-Marc Valin, Koen Vos (October 2010). <a rel="nofollow" class="external text" href="http://tools.ietf.org/html/draft-ietf-codec-opus-00">"Definition of the Opus Audio Codec"</a>. <i>IETF Internet-Drafts</i>. IETF Network Working Group<span class="reference-accessdate">. Retrieved <span class="nowrap">2012-06-11</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=IETF+Internet-Drafts&rft.atitle=Definition+of+the+Opus+Audio+Codec&rft.date=2010-10&rft.au=Jean-Marc+Valin%2C+Koen+Vos&rft_id=http%3A%2F%2Ftools.ietf.org%2Fhtml%2Fdraft-ietf-codec-opus-00&rfr_id=info%3Asid%2Fen.wikipedia.org%3ACELT" class="Z3988"></span></span> </li> <li id="cite_note-ekiga-18"><span class="mw-cite-backlink"><b><a href="#cite_ref-ekiga_18-0">^</a></b></span> <span class="reference-text"><a rel="nofollow" class="external text" href="http://blog.ekiga.net/?p=112">Ekiga 3.1.0 available</a></span> </li> <li id="cite_note-AutoV5-14-19"><span class="mw-cite-backlink"><b><a href="#cite_ref-AutoV5-14_19-0">^</a></b></span> <span class="reference-text"><a rel="nofollow" class="external text" href="http://www.freeswitch.org/node/157">FreeSWITCH: New Release For The New Year</a></span> </li> <li id="cite_note-software-20"><span class="mw-cite-backlink">^ <a href="#cite_ref-software_20-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-software_20-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://celt-codec.org/software/">"Software that uses or supports CELT"</a>. <i>CELT website</i>. Xiph.Org<span class="reference-accessdate">. Retrieved <span class="nowrap">2012-06-12</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=CELT+website&rft.atitle=Software+that+uses+or+supports+CELT&rft_id=http%3A%2F%2Fcelt-codec.org%2Fsoftware%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3ACELT" class="Z3988"></span></span> </li> <li id="cite_note-ffmpeg1-21"><span class="mw-cite-backlink"><b><a href="#cite_ref-ffmpeg1_21-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite id="CITEREFGeorge2011" class="citation web cs1">George, Nicolas (April 20, 2011). <a rel="nofollow" class="external text" href="http://ffmpeg.org/pipermail/ffmpeg-devel/2011-April/110850.html">"[FFmpeg-devel] [PATCH] Support for Xiph CELT/Opus decoding using libcelt"</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=%5BFFmpeg-devel%5D+%5BPATCH%5D+Support+for+Xiph+CELT%2FOpus+decoding+using+libcelt&rft.date=2011-04-20&rft.aulast=George&rft.aufirst=Nicolas&rft_id=http%3A%2F%2Fffmpeg.org%2Fpipermail%2Fffmpeg-devel%2F2011-April%2F110850.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3ACELT" class="Z3988"></span></span> </li> <li id="cite_note-ffmpeg2-22"><span class="mw-cite-backlink"><b><a href="#cite_ref-ffmpeg2_22-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://git.videolan.org/?p=ffmpeg.git;h=89451dd6e4da40ed73b8bbee2d48d8d8be1d5b0c">"git.videolan.org Git - ffmpeg.git/commit"</a>. <i>git.videolan.org</i>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=git.videolan.org&rft.atitle=git.videolan.org+Git+-+ffmpeg.git%2Fcommit&rft_id=http%3A%2F%2Fgit.videolan.org%2F%3Fp%3Dffmpeg.git%3Bh%3D89451dd6e4da40ed73b8bbee2d48d8d8be1d5b0c&rfr_id=info%3Asid%2Fen.wikipedia.org%3ACELT" class="Z3988"></span></span> </li> <li id="cite_note-dota2-23"><span class="mw-cite-backlink"><b><a href="#cite_ref-dota2_23-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://dev.dota2.com/showthread.php?t=43087">"Patch Notes - Dota2 Dev"</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Patch+Notes+-+Dota2+Dev&rft_id=http%3A%2F%2Fdev.dota2.com%2Fshowthread.php%3Ft%3D43087&rfr_id=info%3Asid%2Fen.wikipedia.org%3ACELT" class="Z3988"></span></span> </li> <li id="cite_note-tf2-24"><span class="mw-cite-backlink"><b><a href="#cite_ref-tf2_24-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://www.teamfortress.com/post.php?id=25766">"Team Fortress 2"</a>. <i>www.teamfortress.com</i>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=www.teamfortress.com&rft.atitle=Team+Fortress+2&rft_id=https%3A%2F%2Fwww.teamfortress.com%2Fpost.php%3Fid%3D25766&rfr_id=info%3Asid%2Fen.wikipedia.org%3ACELT" class="Z3988"></span></span> </li> </ol></div> <div class="mw-heading mw-heading2"><h2 id="External_links">External links</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=CELT&action=edit&section=7" title="Edit section: External links"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li><a rel="nofollow" class="external text" href="https://web.archive.org/web/20110228033837/http://www.celt-codec.org/">Official homepage</a></li></ul> <div class="navbox-styles"><style data-mw-deduplicate="TemplateStyles:r1129693374">.mw-parser-output .hlist dl,.mw-parser-output .hlist ol,.mw-parser-output .hlist ul{margin:0;padding:0}.mw-parser-output .hlist dd,.mw-parser-output .hlist dt,.mw-parser-output .hlist li{margin:0;display:inline}.mw-parser-output .hlist.inline,.mw-parser-output .hlist.inline dl,.mw-parser-output .hlist.inline ol,.mw-parser-output .hlist.inline ul,.mw-parser-output .hlist dl dl,.mw-parser-output .hlist dl ol,.mw-parser-output .hlist dl ul,.mw-parser-output .hlist ol dl,.mw-parser-output .hlist ol ol,.mw-parser-output .hlist ol ul,.mw-parser-output .hlist ul dl,.mw-parser-output .hlist ul ol,.mw-parser-output .hlist ul ul{display:inline}.mw-parser-output .hlist .mw-empty-li{display:none}.mw-parser-output .hlist dt::after{content:": "}.mw-parser-output .hlist dd::after,.mw-parser-output .hlist li::after{content:" · ";font-weight:bold}.mw-parser-output .hlist dd:last-child::after,.mw-parser-output .hlist dt:last-child::after,.mw-parser-output .hlist li:last-child::after{content:none}.mw-parser-output .hlist dd dd:first-child::before,.mw-parser-output .hlist dd dt:first-child::before,.mw-parser-output .hlist dd li:first-child::before,.mw-parser-output .hlist dt dd:first-child::before,.mw-parser-output .hlist dt dt:first-child::before,.mw-parser-output .hlist dt li:first-child::before,.mw-parser-output .hlist li dd:first-child::before,.mw-parser-output .hlist li dt:first-child::before,.mw-parser-output .hlist li li:first-child::before{content:" (";font-weight:normal}.mw-parser-output .hlist dd dd:last-child::after,.mw-parser-output .hlist dd dt:last-child::after,.mw-parser-output .hlist dd li:last-child::after,.mw-parser-output .hlist dt dd:last-child::after,.mw-parser-output .hlist dt dt:last-child::after,.mw-parser-output .hlist dt li:last-child::after,.mw-parser-output .hlist li dd:last-child::after,.mw-parser-output .hlist li dt:last-child::after,.mw-parser-output .hlist li li:last-child::after{content:")";font-weight:normal}.mw-parser-output .hlist ol{counter-reset:listitem}.mw-parser-output .hlist ol>li{counter-increment:listitem}.mw-parser-output .hlist ol>li::before{content:" "counter(listitem)"\a0 "}.mw-parser-output .hlist dd ol>li:first-child::before,.mw-parser-output .hlist dt ol>li:first-child::before,.mw-parser-output .hlist li ol>li:first-child::before{content:" ("counter(listitem)"\a0 "}</style><style data-mw-deduplicate="TemplateStyles:r1236075235">.mw-parser-output .navbox{box-sizing:border-box;border:1px solid #a2a9b1;width:100%;clear:both;font-size:88%;text-align:center;padding:1px;margin:1em auto 0}.mw-parser-output .navbox .navbox{margin-top:0}.mw-parser-output .navbox+.navbox,.mw-parser-output .navbox+.navbox-styles+.navbox{margin-top:-1px}.mw-parser-output .navbox-inner,.mw-parser-output .navbox-subgroup{width:100%}.mw-parser-output .navbox-group,.mw-parser-output .navbox-title,.mw-parser-output .navbox-abovebelow{padding:0.25em 1em;line-height:1.5em;text-align:center}.mw-parser-output .navbox-group{white-space:nowrap;text-align:right}.mw-parser-output .navbox,.mw-parser-output .navbox-subgroup{background-color:#fdfdfd}.mw-parser-output .navbox-list{line-height:1.5em;border-color:#fdfdfd}.mw-parser-output .navbox-list-with-group{text-align:left;border-left-width:2px;border-left-style:solid}.mw-parser-output tr+tr>.navbox-abovebelow,.mw-parser-output tr+tr>.navbox-group,.mw-parser-output tr+tr>.navbox-image,.mw-parser-output tr+tr>.navbox-list{border-top:2px solid #fdfdfd}.mw-parser-output .navbox-title{background-color:#ccf}.mw-parser-output .navbox-abovebelow,.mw-parser-output .navbox-group,.mw-parser-output .navbox-subgroup .navbox-title{background-color:#ddf}.mw-parser-output .navbox-subgroup .navbox-group,.mw-parser-output .navbox-subgroup .navbox-abovebelow{background-color:#e6e6ff}.mw-parser-output .navbox-even{background-color:#f7f7f7}.mw-parser-output .navbox-odd{background-color:transparent}.mw-parser-output .navbox .hlist td dl,.mw-parser-output .navbox .hlist td ol,.mw-parser-output .navbox .hlist td ul,.mw-parser-output .navbox td.hlist dl,.mw-parser-output .navbox td.hlist ol,.mw-parser-output .navbox td.hlist ul{padding:0.125em 0}.mw-parser-output .navbox .navbar{display:block;font-size:100%}.mw-parser-output .navbox-title .navbar{float:left;text-align:left;margin-right:0.5em}body.skin--responsive .mw-parser-output .navbox-image img{max-width:none!important}@media print{body.ns-0 .mw-parser-output .navbox{display:none!important}}</style></div><div role="navigation" class="navbox" aria-labelledby="Xiph.Org_Foundation76" style="padding:3px"><table class="nowraplinks mw-collapsible autocollapse navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="col" class="navbox-title" colspan="2"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374" /><style data-mw-deduplicate="TemplateStyles:r1239400231">.mw-parser-output .navbar{display:inline;font-size:88%;font-weight:normal}.mw-parser-output .navbar-collapse{float:left;text-align:left}.mw-parser-output .navbar-boxtext{word-spacing:0}.mw-parser-output .navbar ul{display:inline-block;white-space:nowrap;line-height:inherit}.mw-parser-output .navbar-brackets::before{margin-right:-0.125em;content:"[ "}.mw-parser-output .navbar-brackets::after{margin-left:-0.125em;content:" ]"}.mw-parser-output .navbar li{word-spacing:-0.125em}.mw-parser-output .navbar a>span,.mw-parser-output .navbar a>abbr{text-decoration:inherit}.mw-parser-output .navbar-mini abbr{font-variant:small-caps;border-bottom:none;text-decoration:none;cursor:inherit}.mw-parser-output .navbar-ct-full{font-size:114%;margin:0 7em}.mw-parser-output .navbar-ct-mini{font-size:114%;margin:0 4em}html.skin-theme-clientpref-night .mw-parser-output .navbar li a abbr{color:var(--color-base)!important}@media(prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .navbar li a abbr{color:var(--color-base)!important}}@media print{.mw-parser-output .navbar{display:none!important}}</style><div class="navbar plainlinks hlist navbar-mini"><ul><li class="nv-view"><a href="/wiki/Template:Xiph.org" title="Template:Xiph.org"><abbr title="View this template">v</abbr></a></li><li class="nv-talk"><a href="/wiki/Template_talk:Xiph.org" title="Template talk:Xiph.org"><abbr title="Discuss this template">t</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:Xiph.org" title="Special:EditPage/Template:Xiph.org"><abbr title="Edit this template">e</abbr></a></li></ul></div><div id="Xiph.Org_Foundation76" style="font-size:114%;margin:0 4em"><a href="/wiki/Xiph.Org_Foundation" title="Xiph.Org Foundation">Xiph.Org Foundation</a></div></th></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Ogg" title="Ogg">Ogg Project</a> codecs</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Vorbis" title="Vorbis">Vorbis</a></li> <li><a href="/wiki/Daala" title="Daala">Daala</a></li> <li><a href="/wiki/Theora" title="Theora">Theora</a></li> <li><a href="/wiki/FLAC" title="FLAC">FLAC</a></li> <li><a href="/wiki/Opus_(audio_format)" title="Opus (audio format)">Opus</a></li> <li><a class="mw-selflink selflink">CELT</a></li> <li><a href="/wiki/Speex" title="Speex">Speex</a></li> <li><a href="/wiki/OggPCM" class="mw-redirect" title="OggPCM">OggPCM</a></li> <li><a href="/wiki/Ogg#Ogg_codecs" title="Ogg">Ogg Writ</a></li> <li><a href="/wiki/XML_Shareable_Playlist_Format" title="XML Shareable Playlist Format">XSPF</a></li> <li><a href="/wiki/Annodex" title="Annodex">Annodex</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Media tools</th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Cdparanoia" title="Cdparanoia">cdparanoia</a></li> <li><a href="/wiki/Icecast" title="Icecast">Icecast</a></li> <li><a href="/wiki/Tremor_(software)" title="Tremor (software)">Tremor</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Related articles</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Chris_Montgomery" title="Chris Montgomery">Chris Montgomery</a></li> <li><a href="/wiki/Continuous_Media_Markup_Language" title="Continuous Media Markup Language">CMML</a></li> <li><a href="/wiki/Ogg_page" class="mw-redirect" title="Ogg page">Ogg page</a></li> <li><a href="/wiki/Ogg_Squish" title="Ogg Squish">Ogg Squish</a></li> <li><a href="/wiki/Ogg_formats_in_HTML5" title="Ogg formats in HTML5">Ogg formats in HTML5</a></li> <li><a href="/wiki/Vorbis_comment" title="Vorbis comment">Vorbis comment</a></li> <li><a href="/wiki/List_of_open-source_codecs" title="List of open-source codecs">List of open-source codecs</a></li></ul> </div></td></tr></tbody></table></div> <div class="navbox-styles"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374" /><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236075235" /></div><div role="navigation" class="navbox" aria-labelledby="Multimedia_compression_and_container_formats462" style="padding:3px"><table class="nowraplinks mw-collapsible autocollapse navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="col" class="navbox-title" colspan="2"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374" /><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1239400231" /><div class="navbar plainlinks hlist navbar-mini"><ul><li class="nv-view"><a href="/wiki/Template:Compression_formats" title="Template:Compression formats"><abbr title="View this template">v</abbr></a></li><li class="nv-talk"><a href="/wiki/Template_talk:Compression_formats" title="Template talk:Compression formats"><abbr title="Discuss this template">t</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:Compression_formats" title="Special:EditPage/Template:Compression formats"><abbr title="Edit this template">e</abbr></a></li></ul></div><div id="Multimedia_compression_and_container_formats462" style="font-size:114%;margin:0 4em"><a href="/wiki/Multimedia" title="Multimedia">Multimedia</a> <a href="/wiki/Data_compression" title="Data compression">compression</a> and <a href="/wiki/Container_format_(computing)" class="mw-redirect" title="Container format (computing)">container</a> formats</div></th></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Video_coding_format" title="Video coding format">Video<br />compression</a></th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:5em"><a href="/wiki/International_Organization_for_Standardization" title="International Organization for Standardization">ISO</a>, <a href="/wiki/International_Electrotechnical_Commission" title="International Electrotechnical Commission">IEC</a>, <br /><a href="/wiki/Moving_Picture_Experts_Group" title="Moving Picture Experts Group">MPEG</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/DV_(video_format)" title="DV (video format)">DV</a></li> <li><a href="/wiki/Motion_JPEG" title="Motion JPEG">MJPEG</a></li> <li><a href="/wiki/Motion_JPEG_2000" title="Motion JPEG 2000">Motion JPEG 2000</a></li> <li><a href="/wiki/MPEG-1" title="MPEG-1">MPEG-1</a></li> <li><a href="/wiki/MPEG-2" title="MPEG-2">MPEG-2</a> <ul><li><a href="/wiki/H.262/MPEG-2_Part_2" title="H.262/MPEG-2 Part 2">Part 2</a></li></ul></li> <li><a href="/wiki/MPEG-4" title="MPEG-4">MPEG-4</a> <ul><li><a href="/wiki/MPEG-4_Part_2" title="MPEG-4 Part 2">Part 2 / ASP</a></li> <li><a href="/wiki/H.264/MPEG-4_AVC" class="mw-redirect" title="H.264/MPEG-4 AVC">Part 10 / AVC</a></li> <li><a href="/wiki/MPEG-4_IVC" class="mw-redirect" title="MPEG-4 IVC">Part 33 / IVC</a></li></ul></li> <li><a href="/wiki/MPEG-H" title="MPEG-H">MPEG-H</a> <ul><li><a href="/wiki/High_Efficiency_Video_Coding" title="High Efficiency Video Coding">Part 2 / HEVC</a></li></ul></li> <li><a href="/w/index.php?title=MPEG-I&action=edit&redlink=1" class="new" title="MPEG-I (page does not exist)">MPEG-I</a> <ul><li><a href="/wiki/Versatile_Video_Coding" title="Versatile Video Coding">Part 3 / VVC</a></li></ul></li> <li><a href="/wiki/MPEG-5" class="mw-redirect" title="MPEG-5">MPEG-5</a> <ul><li><a href="/wiki/Essential_Video_Coding" title="Essential Video Coding">Part 1 / EVC</a></li> <li><a href="/wiki/LCEVC" title="LCEVC">Part 2 / LCEVC</a></li></ul></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:5em"><a href="/wiki/ITU-T" title="ITU-T">ITU-T</a>, <a href="/wiki/Video_Coding_Experts_Group" title="Video Coding Experts Group">VCEG</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/H.120" title="H.120">H.120</a></li> <li><a href="/wiki/H.261" title="H.261">H.261</a></li> <li><a href="/wiki/H.262/MPEG-2_Part_2" title="H.262/MPEG-2 Part 2">H.262</a></li> <li><a href="/wiki/H.263" title="H.263">H.263</a></li> <li><a href="/wiki/Advanced_Video_Coding" title="Advanced Video Coding">H.264 / AVC</a></li> <li><a href="/wiki/High_Efficiency_Video_Coding" title="High Efficiency Video Coding">H.265 / HEVC</a></li> <li><a href="/wiki/Versatile_Video_Coding" title="Versatile Video Coding">H.266 / VVC</a></li> <li><a href="/w/index.php?title=H.267&action=edit&redlink=1" class="new" title="H.267 (page does not exist)">H.267 / Enhanced Coding Model</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:5em"><a href="/wiki/Society_of_Motion_Picture_and_Television_Engineers" title="Society of Motion Picture and Television Engineers">SMPTE</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/VC-1" title="VC-1">VC-1</a></li> <li><a href="/wiki/Dirac_(video_compression_format)" title="Dirac (video compression format)">VC-2</a></li> <li><a href="/wiki/Avid_DNxHD" title="Avid DNxHD">VC-3</a></li> <li><a href="/wiki/CineForm" title="CineForm">VC-5</a></li> <li><a href="/wiki/VC-6" title="VC-6">VC-6</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:5em"><a href="/wiki/On2_Technologies" title="On2 Technologies">TrueMotion</a> and AOMedia</th><td class="navbox-list-with-group navbox-list navbox-even" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/On2_Technologies#TrueMotion_S" title="On2 Technologies">TrueMotion S</a></li> <li><a href="/wiki/VP3" title="VP3">VP3</a></li> <li><a href="/wiki/VP6" title="VP6">VP6</a></li> <li><a href="/wiki/VP7" class="mw-redirect" title="VP7">VP7</a></li> <li><a href="/wiki/VP8" title="VP8">VP8</a></li> <li><a href="/wiki/VP9" title="VP9">VP9</a></li> <li><a href="/wiki/AV1" title="AV1">AV1</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:5em">Chinese Standard</th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Audio_Video_Standard#First_generation" title="Audio Video Standard">AVS1 P2/AVS+</a>(GB/T 20090.2/16)</li> <li><a href="/wiki/Audio_Video_Standard#Second_generation" title="Audio Video Standard">AVS2 P2</a>(GB/T 33475.2,GY/T 299.1) <ul><li>HDR Vivid(GY/T 358)</li></ul></li> <li>AVS3 P2(GY/T 368)</li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:5em">Others</th><td class="navbox-list-with-group navbox-list navbox-even" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Apple_Video" title="Apple Video">Apple Video</a></li> <li><a href="/wiki/Audio_Video_Standard" title="Audio Video Standard">AVS</a></li> <li><a href="/wiki/Bink_Video" title="Bink Video">Bink</a></li> <li><a href="/wiki/Cinepak" title="Cinepak">Cinepak</a></li> <li><a href="/wiki/Daala" title="Daala">Daala</a></li> <li><a href="/wiki/Digital_Video_Interactive" title="Digital Video Interactive">DVI</a></li> <li><a href="/wiki/FFV1" title="FFV1">FFV1</a></li> <li><a href="/wiki/Huffyuv" title="Huffyuv">Huffyuv</a></li> <li><a href="/wiki/Indeo" title="Indeo">Indeo</a></li> <li><a href="/wiki/Lagarith" title="Lagarith">Lagarith</a></li> <li><a href="/wiki/Microsoft_Video_1" title="Microsoft Video 1">Microsoft Video 1</a></li> <li><a href="/wiki/MSU_Lossless_Video_Codec" title="MSU Lossless Video Codec">MSU Lossless</a></li> <li><a href="/wiki/OMS_Video" title="OMS Video">OMS Video</a></li> <li><a href="/wiki/Pixlet" title="Pixlet">Pixlet</a></li> <li><a href="/wiki/Apple_ProRes" title="Apple ProRes">ProRes</a> <ul><li><a href="/wiki/ProRes_422" class="mw-redirect" title="ProRes 422">422</a></li> <li><a href="/wiki/ProRes_4444" class="mw-redirect" title="ProRes 4444">4444</a></li></ul></li> <li>QuickTime <ul><li><a href="/wiki/QuickTime_Animation" title="QuickTime Animation">Animation</a></li> <li><a href="/wiki/QuickTime_Graphics" title="QuickTime Graphics">Graphics</a></li></ul></li> <li><a href="/wiki/RealVideo" title="RealVideo">RealVideo</a></li> <li><a href="/wiki/RTVideo" title="RTVideo">RTVideo</a></li> <li><a href="/wiki/SheerVideo" title="SheerVideo">SheerVideo</a></li> <li><a href="/wiki/Smacker_video" title="Smacker video">Smacker</a></li> <li><a href="/wiki/Sorenson_Media" title="Sorenson Media">Sorenson Video/Spark</a></li> <li><a href="/wiki/Theora" title="Theora">Theora</a></li> <li><a href="/wiki/Thor_(video_codec)" title="Thor (video codec)">Thor</a></li> <li><a href="/wiki/Ut_Video_Codec_Suite" title="Ut Video Codec Suite">Ut</a></li> <li><a href="/wiki/Windows_Media_Video" title="Windows Media Video">WMV</a></li> <li><a href="/wiki/RatDVD" title="RatDVD">XEB</a></li> <li><a href="/wiki/YULS" title="YULS">YULS</a></li></ul> </div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Audio_coding_format" title="Audio coding format">Audio<br />compression</a></th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:5em"><a href="/wiki/International_Organization_for_Standardization" title="International Organization for Standardization">ISO</a>, <a href="/wiki/International_Electrotechnical_Commission" title="International Electrotechnical Commission">IEC</a>,<br /> <a href="/wiki/Moving_Picture_Experts_Group" title="Moving Picture Experts Group">MPEG</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/MPEG-1_Audio_Layer_II" title="MPEG-1 Audio Layer II">MPEG-1 Layer II</a> <ul><li><a href="/wiki/MPEG_Multichannel" title="MPEG Multichannel">Multichannel</a></li></ul></li> <li><a href="/wiki/MPEG-1_Audio_Layer_I" title="MPEG-1 Audio Layer I">MPEG-1 Layer I</a></li> <li><a href="/wiki/MP3" title="MP3">MPEG-1 Layer III (MP3)</a></li> <li><a href="/wiki/Advanced_Audio_Coding" title="Advanced Audio Coding">AAC</a> <ul><li><a href="/wiki/High-Efficiency_Advanced_Audio_Coding" title="High-Efficiency Advanced Audio Coding">HE-AAC</a></li> <li><a href="/wiki/AAC-LD" title="AAC-LD">AAC-LD</a></li></ul></li> <li><a href="/wiki/MPEG_Surround" title="MPEG Surround">MPEG Surround</a></li> <li><a href="/wiki/Audio_Lossless_Coding" title="Audio Lossless Coding">MPEG-4 ALS</a></li> <li><a href="/wiki/MPEG-4_SLS" title="MPEG-4 SLS">MPEG-4 SLS</a></li> <li><a href="/wiki/Super_Audio_CD#DST" title="Super Audio CD">MPEG-4 DST</a></li> <li><a href="/wiki/Harmonic_Vector_Excitation_Coding" title="Harmonic Vector Excitation Coding">MPEG-4 HVXC</a></li> <li><a href="/wiki/Code-excited_linear_prediction" title="Code-excited linear prediction">MPEG-4 CELP</a></li> <li><a href="/wiki/Unified_Speech_and_Audio_Coding" title="Unified Speech and Audio Coding">MPEG-D USAC</a></li> <li><a href="/wiki/MPEG-H_3D_Audio" title="MPEG-H 3D Audio">MPEG-H 3D Audio</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:5em"><a href="/wiki/ITU-T" title="ITU-T">ITU-T</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/G.711" title="G.711">G.711</a> <ul><li><a href="/wiki/A-law_algorithm" title="A-law algorithm">A-law</a></li> <li><a href="/wiki/%CE%9C-law_algorithm" title="Μ-law algorithm">µ-law</a></li></ul></li> <li><a href="/wiki/G.718" title="G.718">G.718</a></li> <li><a href="/wiki/G.719" title="G.719">G.719</a></li> <li><a href="/wiki/G.722" title="G.722">G.722</a></li> <li><a href="/wiki/G.722.1" title="G.722.1">G.722.1</a></li> <li><a href="/wiki/Adaptive_Multi-Rate_Wideband" title="Adaptive Multi-Rate Wideband">G.722.2</a></li> <li><a href="/wiki/G.723" title="G.723">G.723</a></li> <li><a href="/wiki/G.723.1" title="G.723.1">G.723.1</a></li> <li><a href="/wiki/G.726" title="G.726">G.726</a></li> <li><a href="/wiki/G.728" title="G.728">G.728</a></li> <li><a href="/wiki/G.729" title="G.729">G.729</a></li> <li><a href="/wiki/G.729.1" title="G.729.1">G.729.1</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:5em"><a href="/wiki/Internet_Engineering_Task_Force" title="Internet Engineering Task Force">IETF</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Opus_(audio_format)" title="Opus (audio format)">Opus</a></li> <li><a href="/wiki/Internet_Low_Bitrate_Codec" title="Internet Low Bitrate Codec">iLBC</a></li> <li><a href="/wiki/Speex" title="Speex">Speex</a></li> <li><a href="/wiki/Vorbis" title="Vorbis">Vorbis</a></li> <li><a href="/wiki/FLAC" title="FLAC">FLAC</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:5em"><a href="/wiki/3GPP" title="3GPP">3GPP</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Adaptive_Multi-Rate_audio_codec" title="Adaptive Multi-Rate audio codec">AMR</a></li> <li><a href="/wiki/Adaptive_Multi-Rate_Wideband" title="Adaptive Multi-Rate Wideband">AMR-WB</a></li> <li><a href="/wiki/Extended_Adaptive_Multi-Rate_%E2%80%93_Wideband" title="Extended Adaptive Multi-Rate – Wideband">AMR-WB+</a></li> <li><a href="/wiki/Enhanced_Variable_Rate_Codec" title="Enhanced Variable Rate Codec">EVRC</a></li> <li><a href="/wiki/Enhanced_Variable_Rate_Codec_B" title="Enhanced Variable Rate Codec B">EVRC-B</a></li> <li><a href="/wiki/Enhanced_Voice_Services" title="Enhanced Voice Services">EVS</a></li> <li><a href="/wiki/Half_Rate" title="Half Rate">GSM-HR</a></li> <li><a href="/wiki/Full_Rate" title="Full Rate">GSM-FR</a></li> <li><a href="/wiki/Enhanced_full_rate" title="Enhanced full rate">GSM-EFR</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:5em"><a href="/wiki/ETSI" class="mw-redirect" title="ETSI">ETSI</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Dolby_Digital" title="Dolby Digital">AC-3</a></li> <li><a href="/wiki/Dolby_AC-4" title="Dolby AC-4">AC-4</a></li> <li><a href="/wiki/DTS_(sound_system)" class="mw-redirect" title="DTS (sound system)">DTS</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:5em"><a href="/wiki/Bluetooth_Special_Interest_Group" title="Bluetooth Special Interest Group">Bluetooth SIG</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/SBC_(codec)" title="SBC (codec)">SBC</a></li> <li><a href="/wiki/LC3_(codec)" title="LC3 (codec)">LC3</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:5em">Chinese Standard</th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Audio_Video_Standard#First_generation" title="Audio Video Standard">AVS1 P10</a>(GB/T 20090.10)</li> <li><a href="/wiki/Audio_Video_Standard#Second_generation" title="Audio Video Standard">AVS2 P3</a>(GB/T 33475.3) <ul><li><a href="/w/index.php?title=Audio_Vivid&action=edit&redlink=1" class="new" title="Audio Vivid (page does not exist)">Audio Vivid</a>(GY/T 363)</li></ul></li> <li><a href="/wiki/Dynamic_Resolution_Adaptation" title="Dynamic Resolution Adaptation">DRA</a>(GB/T 22726)</li> <li>ExAC(SJ/T 11299.4)</li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:5em">Others</th><td class="navbox-list-with-group navbox-list navbox-even" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Algebraic_code-excited_linear_prediction" title="Algebraic code-excited linear prediction">ACELP</a></li> <li><a href="/wiki/Apple_Lossless_Audio_Codec" title="Apple Lossless Audio Codec">ALAC</a></li> <li><a href="/wiki/Asao_(codec)" title="Asao (codec)">Asao</a></li> <li><a href="/wiki/Adaptive_Transform_Acoustic_Coding" class="mw-redirect" title="Adaptive Transform Acoustic Coding">ATRAC</a></li> <li><a class="mw-selflink selflink">CELT</a></li> <li><a href="/wiki/Codec_2" title="Codec 2">Codec 2</a></li> <li><a href="/wiki/Internet_Speech_Audio_Codec" title="Internet Speech Audio Codec">iSAC</a></li> <li><a href="/wiki/Lyra_(codec)" title="Lyra (codec)">Lyra</a></li> <li><a href="/wiki/Mixed-excitation_linear_prediction" title="Mixed-excitation linear prediction">MELP</a></li> <li><a href="/wiki/Monkey%27s_Audio" title="Monkey's Audio">Monkey's Audio</a></li> <li><a href="/wiki/MT9" title="MT9">MT9</a></li> <li><a href="/wiki/Musepack" title="Musepack">Musepack</a></li> <li><a href="/wiki/OptimFROG" title="OptimFROG">OptimFROG</a></li> <li><a href="/wiki/Original_Sound_Quality" title="Original Sound Quality">OSQ</a></li> <li><a href="/wiki/Qualcomm_code-excited_linear_prediction" title="Qualcomm code-excited linear prediction">QCELP</a></li> <li><a href="/wiki/Relaxed_code-excited_linear_prediction" title="Relaxed code-excited linear prediction">RCELP</a></li> <li><a href="/wiki/RealAudio" title="RealAudio">RealAudio</a></li> <li><a href="/wiki/Avid_Audio#Sound_Designer_file_formats" title="Avid Audio">SD2</a></li> <li><a href="/wiki/Shorten_file_format" class="mw-redirect" title="Shorten file format">SHN</a></li> <li><a href="/wiki/SILK" title="SILK">SILK</a></li> <li><a href="/wiki/Siren_(codec)" title="Siren (codec)">Siren</a></li> <li><a href="/wiki/Selectable_Mode_Vocoder" title="Selectable Mode Vocoder">SMV</a></li> <li><a href="/wiki/SVOPC" title="SVOPC">SVOPC</a></li> <li>TTA <ul><li>True Audio</li></ul></li> <li><a href="/wiki/TwinVQ" title="TwinVQ">TwinVQ</a></li> <li><a href="/wiki/Variable-Rate_Multimode_Wideband" title="Variable-Rate Multimode Wideband">VMR-WB</a></li> <li><a href="/wiki/Vector_sum_excited_linear_prediction" title="Vector sum excited linear prediction">VSELP</a></li> <li><a href="/wiki/WavPack" title="WavPack">WavPack</a></li> <li><a href="/wiki/Windows_Media_Audio" title="Windows Media Audio">WMA</a></li> <li><a href="/wiki/Master_Quality_Authenticated" title="Master Quality Authenticated">MQA</a></li> <li><a href="/wiki/AptX" title="AptX">aptX</a></li> <li><a href="/wiki/AptX#aptX_HD" title="AptX">aptX HD</a></li> <li><a href="/wiki/AptX#aptX_Low_Latency" title="AptX">aptX Low Latency</a></li> <li><a href="/wiki/AptX#aptX_Adaptive" title="AptX">aptX Adaptive</a></li> <li><a href="/wiki/LDAC_(codec)" title="LDAC (codec)">LDAC</a></li> <li><a href="/wiki/LHDC_(codec)" title="LHDC (codec)">LHDC</a></li> <li><a href="/wiki/LHDC_(codec)#LLAC" title="LHDC (codec)">LLAC</a></li></ul> </div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Image_compression" title="Image compression">Image<br />compression</a></th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:5em"><a href="/wiki/International_Electrotechnical_Commission" title="International Electrotechnical Commission">IEC</a>, <a href="/wiki/International_Organization_for_Standardization" title="International Organization for Standardization">ISO</a>, <a href="/wiki/Internet_Engineering_Task_Force" title="Internet Engineering Task Force">IETF</a>, <br /><a href="/wiki/World_Wide_Web_Consortium" title="World Wide Web Consortium">W3C</a>, <a href="/wiki/ITU-T" title="ITU-T">ITU-T</a>, <a href="/wiki/Joint_Photographic_Experts_Group" title="Joint Photographic Experts Group">JPEG</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Group_4_compression" title="Group 4 compression">CCITT Group 4</a></li> <li><a href="/wiki/GIF" title="GIF">GIF</a></li> <li><a href="/wiki/High_Efficiency_Image_File_Format#HEIC:_HEVC_in_HEIF" title="High Efficiency Image File Format">HEIC / HEIF</a></li> <li><a href="/wiki/High_Efficiency_Video_Coding#Main_Still_Picture" title="High Efficiency Video Coding">HEVC</a></li> <li><a href="/wiki/JBIG" title="JBIG">JBIG</a></li> <li><a href="/wiki/JBIG2" title="JBIG2">JBIG2</a></li> <li><a href="/wiki/JPEG" title="JPEG">JPEG</a></li> <li><a href="/wiki/JPEG_2000" title="JPEG 2000">JPEG 2000</a></li> <li><a href="/wiki/JPEG-LS" class="mw-redirect" title="JPEG-LS">JPEG-LS</a></li> <li><a href="/wiki/JPEG_XL" title="JPEG XL">JPEG XL</a></li> <li><a href="/wiki/JPEG_XR" title="JPEG XR">JPEG XR</a></li> <li><a href="/wiki/JPEG_XS" title="JPEG XS">JPEG XS</a></li> <li><a href="/wiki/JPEG_XT" title="JPEG XT">JPEG XT</a></li> <li><a href="/wiki/Portable_Network_Graphics" class="mw-redirect" title="Portable Network Graphics">PNG</a></li> <li><a href="/wiki/TIFF" title="TIFF">TIFF</a></li> <li><a href="/wiki/TIFF/EP" title="TIFF/EP">TIFF/EP</a></li> <li><a href="/wiki/TIFF/IT" class="mw-redirect" title="TIFF/IT">TIFF/IT</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:5em">Others</th><td class="navbox-list-with-group navbox-list navbox-even" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/APNG" title="APNG">APNG</a></li> <li><a href="/wiki/AV1" title="AV1">AV1</a></li> <li><a href="/wiki/AVIF" title="AVIF">AVIF</a></li> <li><a href="/wiki/Better_Portable_Graphics" title="Better Portable Graphics">BPG</a></li> <li><a href="/wiki/DjVu" title="DjVu">DjVu</a></li> <li><a href="/wiki/OpenEXR" title="OpenEXR">EXR</a></li> <li><a href="/wiki/Free_Lossless_Image_Format" title="Free Lossless Image Format">FLIF</a></li> <li><a href="/wiki/ICER_(file_format)" title="ICER (file format)">ICER</a></li> <li><a href="/wiki/Multiple-image_Network_Graphics" title="Multiple-image Network Graphics">MNG</a></li> <li><a href="/wiki/Progressive_Graphics_File" title="Progressive Graphics File">PGF</a></li> <li><a href="/wiki/QOI_(image_format)" title="QOI (image format)">QOI</a></li> <li><a href="/wiki/QuickTime_VR" title="QuickTime VR">QTVR</a></li> <li><a href="/wiki/Wireless_Application_Protocol_Bitmap_Format" title="Wireless Application Protocol Bitmap Format">WBMP</a></li> <li><a href="/wiki/WebP" title="WebP">WebP</a></li></ul> </div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Digital_container_format" class="mw-redirect" title="Digital container format">Containers</a></th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:5em"><a href="/wiki/International_Organization_for_Standardization" title="International Organization for Standardization">ISO</a>, <a href="/wiki/International_Electrotechnical_Commission" title="International Electrotechnical Commission">IEC</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/MPEG_elementary_stream" title="MPEG elementary stream">MPEG-ES</a> <ul><li><a href="/wiki/Packetized_elementary_stream" title="Packetized elementary stream">MPEG-PES</a></li></ul></li> <li><a href="/wiki/MPEG_program_stream" title="MPEG program stream">MPEG-PS</a></li> <li><a href="/wiki/MPEG_transport_stream" title="MPEG transport stream">MPEG-TS</a></li> <li><a href="/wiki/ISO/IEC_base_media_file_format" class="mw-redirect" title="ISO/IEC base media file format">ISO/IEC base media file format</a></li> <li><a href="/wiki/MPEG-4_Part_14" class="mw-redirect" title="MPEG-4 Part 14">MPEG-4 Part 14</a> (MP4)</li> <li><a href="/wiki/Motion_JPEG_2000" title="Motion JPEG 2000">Motion JPEG 2000</a></li> <li><a href="/wiki/MPEG-21" title="MPEG-21">MPEG-21 Part 9</a></li> <li><a href="/wiki/MPEG_media_transport" title="MPEG media transport">MPEG media transport</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:5em"><a href="/wiki/ITU-T" title="ITU-T">ITU-T</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/MPEG-2#Systems" title="MPEG-2">H.222.0</a></li> <li><a href="/wiki/Motion_JPEG_2000" title="Motion JPEG 2000">T.802</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:5em"><a href="/wiki/Internet_Engineering_Task_Force" title="Internet Engineering Task Force">IETF</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Real-time_Transport_Protocol" title="Real-time Transport Protocol">RTP</a></li> <li><a href="/wiki/Ogg" title="Ogg">Ogg</a></li> <li><a href="/wiki/Matroska" title="Matroska">Matroska</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:5em"><a href="/wiki/Society_of_Motion_Picture_and_Television_Engineers" title="Society of Motion Picture and Television Engineers">SMPTE</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/General_Exchange_Format" title="General Exchange Format">GXF</a></li> <li><a href="/wiki/Material_Exchange_Format" title="Material Exchange Format">MXF</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:5em">Others</th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/3GP_and_3G2" title="3GP and 3G2">3GP and 3G2</a></li> <li><a href="/wiki/AMV_video_format" title="AMV video format">AMV</a></li> <li><a href="/wiki/Advanced_Systems_Format" title="Advanced Systems Format">ASF</a></li> <li><a href="/wiki/Audio_Interchange_File_Format" title="Audio Interchange File Format">AIFF</a></li> <li><a href="/wiki/Audio_Video_Interleave" title="Audio Video Interleave">AVI</a></li> <li><a href="/wiki/Au_file_format" title="Au file format">AU</a></li> <li><a href="/wiki/Better_Portable_Graphics" title="Better Portable Graphics">BPG</a></li> <li><a href="/wiki/Bink_Video" title="Bink Video">Bink</a> <ul><li><a href="/wiki/Smacker_video" title="Smacker video">Smacker</a></li></ul></li> <li><a href="/wiki/BMP_file_format" title="BMP file format">BMP</a></li> <li><a href="/wiki/DivX#DivX_Media_Format_(DMF)" title="DivX">DivX Media Format</a></li> <li><a href="/wiki/Enhanced_VOB" title="Enhanced VOB">EVO</a></li> <li><a href="/wiki/Flash_Video" title="Flash Video">Flash Video</a></li> <li><a href="/wiki/High_Efficiency_Image_File_Format" title="High Efficiency Image File Format">HEIF</a></li> <li><a href="/wiki/Interchange_File_Format" title="Interchange File Format">IFF</a></li> <li><a href="/wiki/.m2ts" title=".m2ts">M2TS</a></li> <li><a href="/wiki/Matroska" title="Matroska">Matroska</a> <ul><li><a href="/wiki/WebM" title="WebM">WebM</a></li></ul></li> <li><a href="/wiki/QuickTime_File_Format" title="QuickTime File Format">QuickTime File Format</a></li> <li><a href="/wiki/RatDVD" title="RatDVD">RatDVD</a></li> <li><a href="/wiki/RealMedia" title="RealMedia">RealMedia</a></li> <li><a href="/wiki/Resource_Interchange_File_Format" title="Resource Interchange File Format">RIFF</a> <ul><li><a href="/wiki/WAV" title="WAV">WAV</a></li></ul></li> <li><a href="/wiki/MOD_and_TOD" title="MOD and TOD">MOD and TOD</a></li> <li><a href="/wiki/VOB" title="VOB">VOB, IFO and BUP</a></li></ul> </div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Collaborations</th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/NETVC" title="NETVC">NETVC</a></li> <li><a href="/wiki/MPEG_LA" title="MPEG LA">MPEG LA</a></li> <li><a href="/wiki/Alliance_for_Open_Media" title="Alliance for Open Media">Alliance for Open Media</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Data_compression" title="Data compression">Methods</a></th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Entropy_encoding" class="mw-redirect" title="Entropy encoding">Entropy</a> <ul><li><a href="/wiki/Arithmetic_coding" title="Arithmetic coding">Arithmetic</a></li> <li><a href="/wiki/Huffman_coding" title="Huffman coding">Huffman</a></li> <li><a href="/wiki/Modified_Huffman_coding" title="Modified Huffman coding">Modified</a></li></ul></li> <li><a href="/wiki/Linear_predictive_coding" title="Linear predictive coding">LPC</a> <ul><li><a href="/wiki/Algebraic_code-excited_linear_prediction" title="Algebraic code-excited linear prediction">ACELP</a></li> <li><a href="/wiki/Code-excited_linear_prediction" title="Code-excited linear prediction">CELP</a></li> <li><a href="/wiki/Line_spectral_pairs" title="Line spectral pairs">LSP</a></li> <li><a href="/wiki/Warped_linear_predictive_coding" title="Warped linear predictive coding">WLPC</a></li></ul></li> <li><a href="/wiki/Lossless_compression" title="Lossless compression">Lossless</a></li> <li><a href="/wiki/Lossy_compression" title="Lossy compression">Lossy</a></li> <li><a href="/wiki/LZ77_and_LZ78" title="LZ77 and LZ78">LZ</a> <ul><li><a href="/wiki/DEFLATE" class="mw-redirect" title="DEFLATE">DEFLATE</a></li> <li><a href="/wiki/Lempel%E2%80%93Ziv%E2%80%93Welch" title="Lempel–Ziv–Welch">LZW</a></li></ul></li> <li><a href="/wiki/Pulse-code_modulation" title="Pulse-code modulation">PCM</a> <ul><li><a href="/wiki/A-law_algorithm" title="A-law algorithm">A-law</a></li> <li><a href="/wiki/%CE%9C-law_algorithm" title="Μ-law algorithm">µ-law</a></li> <li><a href="/wiki/Adaptive_differential_pulse-code_modulation" title="Adaptive differential pulse-code modulation">ADPCM</a></li> <li><a href="/wiki/Differential_pulse-code_modulation" title="Differential pulse-code modulation">DPCM</a></li></ul></li> <li><a href="/wiki/Transform_coding" title="Transform coding">Transforms</a> <ul><li><a href="/wiki/Discrete_cosine_transform" title="Discrete cosine transform">DCT</a></li> <li><a href="/wiki/Fast_Fourier_transform" title="Fast Fourier transform">FFT</a></li> <li><a href="/wiki/Modified_discrete_cosine_transform" title="Modified discrete cosine transform">MDCT</a></li> <li><a href="/wiki/Wavelet" title="Wavelet">Wavelet</a> <ul><li><a href="/wiki/Daubechies_wavelet" title="Daubechies wavelet">Daubechies</a></li> <li><a href="/wiki/Discrete_wavelet_transform" title="Discrete wavelet transform">DWT</a></li></ul></li></ul></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Lists</th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Comparison_of_audio_coding_formats" title="Comparison of audio coding formats">Comparison of audio coding formats</a></li> <li><a href="/wiki/Comparison_of_video_codecs" title="Comparison of video codecs">Comparison of video codecs</a></li> <li><a href="/wiki/List_of_codecs" title="List of codecs">List of codecs</a></li></ul> </div></td></tr><tr><td class="navbox-abovebelow" colspan="2"><div>See <a href="/wiki/Template:Compression_methods" title="Template:Compression methods">Compression methods</a> for techniques and <a href="/wiki/Template:Compression_software" title="Template:Compression software">Compression software</a> for codecs</div></td></tr></tbody></table></div> <div class="navbox-styles"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374" /><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236075235" /></div><div role="navigation" class="navbox" aria-labelledby="Data_compression_software612" style="padding:3px"><table class="nowraplinks hlist mw-collapsible autocollapse navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="col" class="navbox-title" colspan="2"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374" /><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1239400231" /><div class="navbar plainlinks hlist navbar-mini"><ul><li class="nv-view"><a href="/wiki/Template:Compression_software" title="Template:Compression software"><abbr title="View this template">v</abbr></a></li><li class="nv-talk"><a href="/wiki/Template_talk:Compression_software" title="Template talk:Compression software"><abbr title="Discuss this template">t</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:Compression_software" title="Special:EditPage/Template:Compression software"><abbr title="Edit this template">e</abbr></a></li></ul></div><div id="Data_compression_software612" style="font-size:114%;margin:0 4em"><a href="/wiki/Data_compression" title="Data compression">Data compression</a> software</div></th></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Comparison_of_file_archivers" title="Comparison of file archivers">Archivers</a> with<br /> compression<br /> <span style="font-size: 85%;">(<a href="/wiki/Comparison_of_file_archivers" title="Comparison of file archivers">comparison</a>)</span></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:7em"><a href="/wiki/Free_software" title="Free software">Free software</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/7-Zip" title="7-Zip">7-Zip</a></li> <li><a href="/wiki/Ark_(software)" title="Ark (software)">Ark</a></li> <li><a href="/wiki/Haiku_Applications#Expander" class="mw-redirect" title="Haiku Applications">Expander</a></li> <li><a href="/wiki/FreeArc" title="FreeArc">FreeArc</a></li> <li><a href="/wiki/GNOME_Archive_Manager" class="mw-redirect" title="GNOME Archive Manager">GNOME Archive Manager</a></li> <li><a href="/wiki/Info-ZIP" title="Info-ZIP">Info-ZIP</a></li> <li><a href="/wiki/KGB_Archiver" title="KGB Archiver">KGB Archiver</a></li> <li><a href="/wiki/PAQ" title="PAQ">PAQ</a></li> <li><a href="/wiki/Pax_(command)" title="Pax (command)">pax</a></li> <li><a href="/wiki/PeaZip" title="PeaZip">PeaZip</a></li> <li><a href="/wiki/XAD_(software)" title="XAD (software)">XAD</a> (decompression only)</li> <li><a href="/wiki/Xarchiver" title="Xarchiver">Xarchiver</a></li> <li><a href="/wiki/Zipeg" title="Zipeg">Zipeg</a></li> <li><a href="/wiki/ZPAQ" title="ZPAQ">ZPAQ</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:7em"><a href="/wiki/Freeware" title="Freeware">Freeware</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Filzip" title="Filzip">Filzip</a></li> <li><a href="/wiki/LHA_(file_format)" title="LHA (file format)">LHA</a></li> <li><a href="/wiki/Lhasa_(computing)" title="Lhasa (computing)">Lhasa</a> (decompression only)</li> <li><a href="/wiki/StuffIt_Expander" title="StuffIt Expander">StuffIt Expander</a> (decompression only)</li> <li><a href="/wiki/The_Unarchiver" title="The Unarchiver">The Unarchiver</a> (decompression only)</li> <li><a href="/wiki/TUGZip" title="TUGZip">TUGZip</a></li> <li><a href="/wiki/ZipGenius" title="ZipGenius">ZipGenius</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:7em"><a href="/wiki/Commercial_software" title="Commercial software">Commercial</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/ARC_(file_format)" title="ARC (file format)">ARC</a></li> <li><a href="/wiki/ALZip" title="ALZip">ALZip</a></li> <li><a href="/wiki/Archive_Utility" class="mw-redirect" title="Archive Utility">Archive Utility</a></li> <li><a href="/wiki/ARJ" title="ARJ">ARJ</a></li> <li><a href="/wiki/BetterZip" title="BetterZip">BetterZip</a></li> <li><a href="/wiki/MacBinary" title="MacBinary">MacBinary</a></li> <li><a href="/wiki/PKZIP" title="PKZIP">PKZIP/SecureZIP</a></li> <li><a href="/wiki/PowerArchiver" title="PowerArchiver">PowerArchiver</a></li> <li><a href="/wiki/StuffIt" title="StuffIt">StuffIt</a></li> <li><a href="/wiki/WinAce" title="WinAce">WinAce</a></li> <li><a href="/wiki/WinRAR" title="WinRAR">WinRAR</a></li> <li><a href="/wiki/WinZip" title="WinZip">WinZip</a></li></ul> </div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Non-archiving<br />compressors</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:7em">Generic</th><td class="navbox-list-with-group navbox-list navbox-even" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Bzip2" title="Bzip2">bzip2</a></li> <li><a href="/wiki/Compress_(software)" title="Compress (software)">compress</a></li> <li><a href="/wiki/Gzip" title="Gzip">gzip</a></li> <li><a href="/wiki/Lzip" title="Lzip">lzip</a></li> <li><a href="/wiki/Lzop" title="Lzop">lzop</a></li> <li><a href="/wiki/Pack_(software)" title="Pack (software)">pack</a></li> <li><a href="/wiki/Rzip" title="Rzip">rzip</a></li> <li><a href="/wiki/Snappy_(compression)" title="Snappy (compression)">Snappy</a></li> <li><a href="/wiki/XZ_Utils" title="XZ Utils">XZ Utils</a></li> <li><a href="/wiki/Zstd" title="Zstd">zstd</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:7em"><a href="/wiki/Executable_compression" title="Executable compression">For code</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"><a href="/wiki/UPX" title="UPX">UPX</a></div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Data_compression#Audio" title="Data compression">Audio<br /> compression</a><br /> <span style="font-size: 85%;">(<a href="/wiki/Comparison_of_audio_coding_formats" title="Comparison of audio coding formats">comparison</a>)</span></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:7em;padding-top:5px; padding-bottom:5px"><a href="/wiki/Lossy_compression" title="Lossy compression">Lossy</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Advanced_Audio_Coding" title="Advanced Audio Coding">AAC</a> <ul><li><a href="/wiki/Fraunhofer_FDK_AAC" title="Fraunhofer FDK AAC">Fraunhofer FDK AAC</a></li> <li><a href="/wiki/Nero_AAC_Codec" title="Nero AAC Codec">Nero AAC Codec</a></li> <li><a href="/wiki/FAAC" title="FAAC">FAAC</a></li></ul></li> <li><a href="/wiki/Helix_(multimedia_project)" title="Helix (multimedia project)">Helix DNA Producer</a></li> <li><a href="/wiki/MP3" title="MP3">MP3</a> <ul><li><a href="/wiki/L3enc" title="L3enc">l3enc</a></li> <li><a href="/wiki/LAME" title="LAME">LAME</a></li></ul></li> <li><a href="/wiki/TooLAME" title="TooLAME">TooLAME</a></li> <li><a href="/wiki/Libavcodec" title="Libavcodec">libavcodec</a></li> <li><a class="mw-selflink selflink">libcelt</a></li> <li><a href="/wiki/Opus_(audio_format)" title="Opus (audio format)">libopus</a></li> <li><a href="/wiki/Speex" title="Speex">libspeex</a></li> <li><a href="/wiki/Musepack" title="Musepack">Musepack</a></li> <li><a href="/wiki/Vorbis" title="Vorbis">libvorbis</a></li> <li><a href="/wiki/Windows_Media_Encoder" title="Windows Media Encoder">Windows Media Encoder</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:7em;padding-top:5px; padding-bottom:5px"><a href="/wiki/Lossless_compression" title="Lossless compression">Lossless</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Apple_Lossless_Audio_Codec" title="Apple Lossless Audio Codec">ALAC</a></li> <li><a href="/wiki/FLAC" title="FLAC">FLAC</a></li> <li><a href="/wiki/Libavcodec" title="Libavcodec">libavcodec</a></li> <li><a href="/wiki/Monkey%27s_Audio" title="Monkey's Audio">Monkey's Audio</a></li> <li><a href="/wiki/Audio_Lossless_Coding" title="Audio Lossless Coding">mp4als</a></li> <li><a href="/wiki/OptimFROG" title="OptimFROG">OptimFROG</a></li> <li><a href="/wiki/Shorten_(codec)" title="Shorten (codec)">Shorten</a></li> <li><a href="/wiki/WavPack" title="WavPack">WavPack</a></li></ul> </div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Data_compression#Video" title="Data compression">Video<br /> compression</a><br /> <span style="font-size: 85%;">(<a href="/wiki/Comparison_of_video_codecs" title="Comparison of video codecs">comparison</a>)</span></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:7em"><a href="/wiki/Lossy_compression" title="Lossy compression">Lossy</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/MPEG-4_Part_2" title="MPEG-4 Part 2">MPEG-4 ASP</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/3ivx" title="3ivx">3ivx</a></li> <li><a href="/wiki/DivX" title="DivX">DivX</a></li> <li><a href="/wiki/Nero_Digital" title="Nero Digital">Nero Digital</a></li> <li><a href="/wiki/FFmpeg" title="FFmpeg">FFmpeg</a></li> <li><a href="/wiki/HDX4" title="HDX4">HDX4</a></li> <li><a href="/wiki/Xvid" title="Xvid">Xvid</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Advanced_Video_Coding" title="Advanced Video Coding">H.264</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/CoreAVC" title="CoreAVC">CoreAVC</a></li> <li>Blu-code</li> <li><a href="/wiki/DivX" title="DivX">DivX</a></li> <li><a href="/wiki/FFmpeg" title="FFmpeg">FFmpeg</a></li> <li><a href="/wiki/Nero_Digital" title="Nero Digital">Nero Digital</a></li> <li><a href="/wiki/OpenH264" title="OpenH264">OpenH264</a></li> <li><a href="/wiki/QuickTime" title="QuickTime">QuickTime</a></li> <li><a href="/wiki/X264" title="X264">x264</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/High_Efficiency_Video_Coding" title="High Efficiency Video Coding">HEVC</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/DivX" title="DivX">DivX</a></li> <li><a href="/wiki/X265" title="X265">x265</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Others</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/CineForm" title="CineForm">CineForm</a></li> <li><a href="/wiki/Cinepak" title="Cinepak">Cinepak</a></li> <li><a href="/wiki/Daala" title="Daala">Daala</a></li> <li><a href="/wiki/Avid_DNxHD" title="Avid DNxHD">DNxHD</a></li> <li><a href="/wiki/Helix_(multimedia_project)" title="Helix (multimedia project)">Helix DNA Producer</a></li> <li><a href="/wiki/Indeo" title="Indeo">Indeo</a></li> <li><a href="/wiki/Libavcodec" title="Libavcodec">libavcodec</a></li> <li><a href="/wiki/Dirac_(video_compression_format)" title="Dirac (video compression format)">Schrödinger (Dirac)</a></li> <li><a href="/wiki/Smart_Bitrate_Control" title="Smart Bitrate Control">SBC</a></li> <li><a href="/wiki/Sorenson_codec" class="mw-redirect" title="Sorenson codec">Sorenson</a></li> <li><a href="/wiki/VP7" class="mw-redirect" title="VP7">VP7</a></li> <li><a href="/wiki/Theora" title="Theora">libtheora</a></li> <li><a href="/wiki/Libvpx" title="Libvpx">libvpx</a></li> <li><a href="/wiki/Windows_Media_Encoder" title="Windows Media Encoder">Windows Media Encoder</a></li></ul> </div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:7em"><a href="/wiki/Lossless_compression" title="Lossless compression">Lossless</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/FFV1" title="FFV1">FFV1</a></li> <li><a href="/wiki/Huffyuv" title="Huffyuv">Huffyuv</a></li> <li><a href="/wiki/Lagarith" title="Lagarith">Lagarith</a></li> <li><a href="/wiki/MSU_Lossless_Video_Codec" title="MSU Lossless Video Codec">MSU Lossless</a></li> <li><a href="/wiki/YULS" title="YULS">YULS</a></li></ul> </div></td></tr></tbody></table><div></div></td></tr><tr><td class="navbox-abovebelow" colspan="2"><div> <ul><li>See also: <a href="/wiki/Template:Compression_methods" title="Template:Compression methods">compression methods</a> and <a href="/wiki/Template:Compression_formats" title="Template:Compression formats">compression formats</a></li></ul> </div></td></tr></tbody></table></div>    </div><noscript><img src="https://auth.wikimedia.org/loginwiki/wiki/Special:CentralAutoLogin/start?useformat=desktop&type=1x1&usesul3=1" alt="" width="1" height="1" style="border: none; position: absolute;"></noscript> <div class="printfooter" data-nosnippet="">Retrieved from "<a dir="ltr" href="https://en.wikipedia.org/w/index.php?title=CELT&oldid=1221001953">https://en.wikipedia.org/w/index.php?title=CELT&oldid=1221001953</a>"</div></div> <div id="catlinks" class="catlinks" data-mw="interface"><div id="mw-normal-catlinks" class="mw-normal-catlinks"><a href="/wiki/Help:Category" title="Help:Category">Categories</a>: <ul><li><a href="/wiki/Category:Speech_codecs" title="Category:Speech codecs">Speech codecs</a></li><li><a href="/wiki/Category:Free_audio_codecs" title="Category:Free audio codecs">Free audio codecs</a></li><li><a href="/wiki/Category:Xiph.Org_projects" title="Category:Xiph.Org projects">Xiph.Org projects</a></li></ul></div><div id="mw-hidden-catlinks" class="mw-hidden-catlinks mw-hidden-cats-hidden">Hidden categories: <ul><li><a href="/wiki/Category:Webarchive_template_wayback_links" title="Category:Webarchive template wayback links">Webarchive template wayback links</a></li><li><a href="/wiki/Category:CS1_German-language_sources_(de)" title="Category:CS1 German-language sources (de)">CS1 German-language sources (de)</a></li><li><a href="/wiki/Category:Articles_with_short_description" title="Category:Articles with short description">Articles with short description</a></li><li><a href="/wiki/Category:Short_description_is_different_from_Wikidata" title="Category:Short description is different from Wikidata">Short description is different from Wikidata</a></li></ul></div></div> </div> </main> </div> <div class="mw-footer-container"> <footer id="footer" class="mw-footer" > <ul id="footer-info"> <li id="footer-info-lastmod"> This page was last edited on 27 April 2024, at 06:58<span class="anonymous-show"> (UTC)</span>.</li> <li id="footer-info-copyright">Text is available under the <a href="/wiki/Wikipedia:Text_of_the_Creative_Commons_Attribution-ShareAlike_4.0_International_License" title="Wikipedia:Text of the Creative Commons Attribution-ShareAlike 4.0 International License">Creative Commons Attribution-ShareAlike 4.0 License</a>; additional terms may apply. By using this site, you agree to the <a href="https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Terms_of_Use" class="extiw" title="foundation:Special:MyLanguage/Policy:Terms of Use">Terms of Use</a> and <a href="https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Privacy_policy" class="extiw" title="foundation:Special:MyLanguage/Policy:Privacy policy">Privacy Policy</a>. Wikipedia® is a registered trademark of the <a rel="nofollow" class="external text" href="https://wikimediafoundation.org/">Wikimedia Foundation, Inc.</a>, a non-profit organization.</li> </ul> <ul id="footer-places"> <li id="footer-places-privacy"><a href="https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Privacy_policy">Privacy policy</a></li> <li id="footer-places-about"><a href="/wiki/Wikipedia:About">About Wikipedia</a></li> <li id="footer-places-disclaimers"><a href="/wiki/Wikipedia:General_disclaimer">Disclaimers</a></li> <li id="footer-places-contact"><a href="//en.wikipedia.org/wiki/Wikipedia:Contact_us">Contact Wikipedia</a></li> <li id="footer-places-wm-codeofconduct"><a href="https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Universal_Code_of_Conduct">Code of Conduct</a></li> <li id="footer-places-developers"><a href="https://developer.wikimedia.org">Developers</a></li> <li id="footer-places-statslink"><a href="https://stats.wikimedia.org/#/en.wikipedia.org">Statistics</a></li> <li id="footer-places-cookiestatement"><a href="https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Cookie_statement">Cookie statement</a></li> <li id="footer-places-mobileview"><a href="//en.m.wikipedia.org/w/index.php?title=CELT&mobileaction=toggle_view_mobile" class="noprint stopMobileRedirectToggle">Mobile view</a></li> </ul> <ul id="footer-icons" class="noprint"> <li id="footer-copyrightico"><a href="https://www.wikimedia.org/" class="cdx-button cdx-button--fake-button cdx-button--size-large cdx-button--fake-button--enabled"><picture><source media="(min-width: 500px)" srcset="/static/images/footer/wikimedia-button.svg" width="84" height="29"><img src="/static/images/footer/wikimedia.svg" width="25" height="25" alt="Wikimedia Foundation" lang="en" loading="lazy"></picture></a></li> <li id="footer-poweredbyico"><a href="https://www.mediawiki.org/" class="cdx-button cdx-button--fake-button cdx-button--size-large cdx-button--fake-button--enabled"><picture><source media="(min-width: 500px)" srcset="/w/resources/assets/poweredby_mediawiki.svg" width="88" height="31"><img src="/w/resources/assets/mediawiki_compact.svg" alt="Powered by MediaWiki" lang="en" width="25" height="25" loading="lazy"></picture></a></li> </ul> </footer> </div> </div> </div> <div class="vector-header-container vector-sticky-header-container"> <div id="vector-sticky-header" class="vector-sticky-header"> <div class="vector-sticky-header-start"> <div class="vector-sticky-header-icon-start vector-button-flush-left vector-button-flush-right" aria-hidden="true"> <button class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-sticky-header-search-toggle" tabindex="-1" data-event-name="ui.vector-sticky-search-form.icon"><span class="vector-icon mw-ui-icon-search mw-ui-icon-wikimedia-search"></span> <span>Search</span> </button> </div> <div role="search" class="vector-search-box-vue vector-search-box-show-thumbnail vector-search-box"> <div class="vector-typeahead-search-container"> <div class="cdx-typeahead-search cdx-typeahead-search--show-thumbnail"> <form action="/w/index.php" id="vector-sticky-search-form" class="cdx-search-input cdx-search-input--has-end-button"> <div class="cdx-search-input__input-wrapper" data-search-loc="header-moved"> <div class="cdx-text-input cdx-text-input--has-start-icon"> <input class="cdx-text-input__input" type="search" name="search" placeholder="Search Wikipedia"> <span class="cdx-text-input__icon cdx-text-input__start-icon"></span> </div> <input type="hidden" name="title" value="Special:Search"> </div> <button class="cdx-button cdx-search-input__end-button">Search</button> </form> </div> </div> </div> <div class="vector-sticky-header-context-bar"> <nav aria-label="Contents" class="vector-toc-landmark"> <div id="vector-sticky-header-toc" class="vector-dropdown mw-portlet mw-portlet-sticky-header-toc vector-sticky-header-toc vector-button-flush-left" > <input type="checkbox" id="vector-sticky-header-toc-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-sticky-header-toc" class="vector-dropdown-checkbox " aria-label="Toggle the table of contents" > <label id="vector-sticky-header-toc-label" for="vector-sticky-header-toc-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" ><span class="vector-icon mw-ui-icon-listBullet mw-ui-icon-wikimedia-listBullet"></span> <span class="vector-dropdown-label-text">Toggle the table of contents</span> </label> <div class="vector-dropdown-content"> <div id="vector-sticky-header-toc-unpinned-container" class="vector-unpinned-container"> </div> </div> </div> </nav> <div class="vector-sticky-header-context-bar-primary" aria-hidden="true" ><span class="mw-page-title-main">CELT</span></div> </div> </div> <div class="vector-sticky-header-end" aria-hidden="true"> <div class="vector-sticky-header-icons"> <a href="#" class="cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only" id="ca-talk-sticky-header" tabindex="-1" data-event-name="talk-sticky-header"><span class="vector-icon mw-ui-icon-speechBubbles mw-ui-icon-wikimedia-speechBubbles"></span> <span></span> </a> <a href="#" class="cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only" id="ca-subject-sticky-header" tabindex="-1" data-event-name="subject-sticky-header"><span class="vector-icon mw-ui-icon-article mw-ui-icon-wikimedia-article"></span> <span></span> </a> <a href="#" class="cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only" id="ca-history-sticky-header" tabindex="-1" data-event-name="history-sticky-header"><span class="vector-icon mw-ui-icon-wikimedia-history mw-ui-icon-wikimedia-wikimedia-history"></span> <span></span> </a> <a href="#" class="cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only mw-watchlink" id="ca-watchstar-sticky-header" tabindex="-1" data-event-name="watch-sticky-header"><span class="vector-icon mw-ui-icon-wikimedia-star mw-ui-icon-wikimedia-wikimedia-star"></span> <span></span> </a> <a href="#" class="cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only" id="ca-edit-sticky-header" tabindex="-1" data-event-name="wikitext-edit-sticky-header"><span class="vector-icon mw-ui-icon-wikimedia-wikiText mw-ui-icon-wikimedia-wikimedia-wikiText"></span> <span></span> </a> <a href="#" class="cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only" id="ca-ve-edit-sticky-header" tabindex="-1" data-event-name="ve-edit-sticky-header"><span class="vector-icon mw-ui-icon-wikimedia-edit mw-ui-icon-wikimedia-wikimedia-edit"></span> <span></span> </a> <a href="#" class="cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only" id="ca-viewsource-sticky-header" tabindex="-1" data-event-name="ve-edit-protected-sticky-header"><span class="vector-icon mw-ui-icon-wikimedia-editLock mw-ui-icon-wikimedia-wikimedia-editLock"></span> <span></span> </a> </div> <div class="vector-sticky-header-buttons"> <button class="cdx-button cdx-button--weight-quiet mw-interlanguage-selector" id="p-lang-btn-sticky-header" tabindex="-1" data-event-name="ui.dropdown-p-lang-btn-sticky-header"><span class="vector-icon mw-ui-icon-wikimedia-language mw-ui-icon-wikimedia-wikimedia-language"></span> <span>5 languages</span> </button> <a href="#" class="cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--action-progressive" id="ca-addsection-sticky-header" tabindex="-1" data-event-name="addsection-sticky-header"><span class="vector-icon mw-ui-icon-speechBubbleAdd-progressive mw-ui-icon-wikimedia-speechBubbleAdd-progressive"></span> <span>Add topic</span> </a> </div> <div class="vector-sticky-header-icon-end"> <div class="vector-user-links"> </div> </div> </div> </div> </div> <div class="mw-portlet mw-portlet-dock-bottom emptyPortlet" id="p-dock-bottom"> <ul> </ul> </div> <script>(RLQ=window.RLQ||[]).push(function(){mw.config.set({"wgHostname":"mw-web.codfw.main-f968fbb9b-gl4pr","wgBackendResponseTime":168,"wgPageParseReport":{"limitreport":{"cputime":"0.530","walltime":"0.671","ppvisitednodes":{"value":2971,"limit":1000000},"postexpandincludesize":{"value":155146,"limit":2097152},"templateargumentsize":{"value":3359,"limit":2097152},"expansiondepth":{"value":27,"limit":100},"expensivefunctioncount":{"value":7,"limit":500},"unstrip-depth":{"value":1,"limit":20},"unstrip-size":{"value":91603,"limit":5000000},"entityaccesscount":{"value":1,"limit":400},"timingprofile":["100.00% 541.472 1 -total"," 34.59% 187.290 1 Template:Reflist"," 23.91% 129.451 12 Template:Navbox"," 23.57% 127.600 13 Template:Cite_web"," 21.07% 114.113 3 Template:Infobox"," 15.06% 81.530 1 Template:Short_description"," 14.53% 78.654 1 Template:Xiph.org"," 9.93% 53.792 1 Template:Infobox_software"," 8.94% 48.430 2 Template:Pagetype"," 8.03% 43.493 1 Template:Infobox_file_format"]},"scribunto":{"limitreport-timeusage":{"value":"0.296","limit":"10.000"},"limitreport-memusage":{"value":6462800,"limit":52428800}},"cachereport":{"origin":"mw-web.codfw.main-5c6f46dcf-b2jzk","timestamp":"20250331074128","ttl":2592000,"transientcontent":false}}});});</script> <script type="application/ld+json">{"@context":"https:\/\/schema.org","@type":"Article","name":"CELT","url":"https:\/\/en.wikipedia.org\/wiki\/CELT","sameAs":"http:\/\/www.wikidata.org\/entity\/Q1128269","mainEntity":"http:\/\/www.wikidata.org\/entity\/Q1128269","author":{"@type":"Organization","name":"Contributors to Wikimedia projects"},"publisher":{"@type":"Organization","name":"Wikimedia Foundation, Inc.","logo":{"@type":"ImageObject","url":"https:\/\/www.wikimedia.org\/static\/images\/wmf-hor-googpub.png"}},"datePublished":"2009-02-23T02:51:04Z","dateModified":"2024-04-27T06:58:39Z","headline":"audio compression codec"}</script> </body> </html>