CINXE.COM

<!DOCTYPE html> <html class="client-nojs vector-feature-language-in-header-enabled vector-feature-language-in-main-page-header-disabled vector-feature-sticky-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-toc-available" lang="en" dir="ltr"> <head> <meta charset="UTF-8"> <title>Lossy compression - Wikipedia</title> <script>(function(){var className="client-js vector-feature-language-in-header-enabled vector-feature-language-in-main-page-header-disabled vector-feature-sticky-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-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":"b3fca764-bf72-4cfd-a9d5-fae854ed8d93","wgCanonicalNamespace":"","wgCanonicalSpecialPageName":false,"wgNamespaceNumber":0,"wgPageName":"Lossy_compression","wgTitle":"Lossy compression","wgCurRevisionId":1254927363,"wgRevisionId":1254927363,"wgArticleId":18208,"wgIsArticle":true,"wgIsRedirect":false,"wgAction":"view","wgUserName":null,"wgUserGroups":["*"],"wgCategories":["Articles with short description","Short description is different from Wikidata","All articles with unsourced statements","Articles with unsourced statements from November 2019","Webarchive template wayback links","Data compression","Lossy compression algorithms"],"wgPageViewLanguage":"en","wgPageContentLanguage":"en","wgPageContentModel":"wikitext","wgRelevantPageName":"Lossy_compression","wgRelevantArticleId":18208,"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":30000,"wgRelatedArticlesCompat":[],"wgCentralAuthMobileDomain":false,"wgEditSubmitButtonLabelPublish":true,"wgULSPosition":"interlanguage","wgULSisCompactLinksEnabled":false,"wgVector2022LanguageInHeader":true,"wgULSisLanguageSelectorEmpty":false,"wgWikibaseItemId":"Q55564","wgCheckUserClientHintsHeadersJsApi":["brands","architecture","bitness","fullVersionList","mobile","model","platform","platformVersion"],"GEHomepageSuggestedEditsEnableTopics":true,"wgGETopicsMatchModeEnabled": false,"wgGEStructuredTaskRejectionReasonTextInputEnabled":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","ext.wikimediaBadges":"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.growthExperiments.SuggestedEditSession","wikibase.sidebar.tracking"];</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.wikimediaBadges%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.4"> <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 property="og:image" content="https://upload.wikimedia.org/wikipedia/commons/a/a4/Comparison_of_JPEG_and_PNG.png"> <meta property="og:image:width" content="1200"> <meta property="og:image:height" content="1200"> <meta property="og:image" content="https://upload.wikimedia.org/wikipedia/commons/a/a4/Comparison_of_JPEG_and_PNG.png"> <meta property="og:image:width" content="800"> <meta property="og:image:height" content="800"> <meta property="og:image:width" content="640"> <meta property="og:image:height" content="640"> <meta name="viewport" content="width=1120"> <meta property="og:title" content="Lossy compression - 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/Lossy_compression"> <link rel="alternate" type="application/x-wiki" title="Edit this page" href="/w/index.php?title=Lossy_compression&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/Lossy_compression"> <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="//login.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-Lossy_compression rootpage-Lossy_compression 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" > <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> </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/wiki/Special:FundraiserRedirector?utm_source=donate&utm_medium=sidebar&utm_campaign=C13_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=Lossy+compression" 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=Lossy+compression" 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/wiki/Special:FundraiserRedirector?utm_source=donate&utm_medium=sidebar&utm_campaign=C13_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=Lossy+compression" 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=Lossy+compression" 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-Types" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Types"> <div class="vector-toc-text"> <span class="vector-toc-numb">1</span> <span>Types</span> </div> </a> <ul id="toc-Types-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Transform_coding" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Transform_coding"> <div class="vector-toc-text"> <span class="vector-toc-numb">2</span> <span>Transform coding</span> </div> </a> <ul id="toc-Transform_coding-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Information_loss" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Information_loss"> <div class="vector-toc-text"> <span class="vector-toc-numb">3</span> <span>Information loss</span> </div> </a> <ul id="toc-Information_loss-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Comparison" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Comparison"> <div class="vector-toc-text"> <span class="vector-toc-numb">4</span> <span>Comparison</span> </div> </a> <button aria-controls="toc-Comparison-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> <span class="vector-icon mw-ui-icon-wikimedia-expand"></span> <span>Toggle Comparison subsection</span> </button> <ul id="toc-Comparison-sublist" class="vector-toc-list"> <li id="toc-Transparency" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Transparency"> <div class="vector-toc-text"> <span class="vector-toc-numb">4.1</span> <span>Transparency</span> </div> </a> <ul id="toc-Transparency-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Compression_ratio" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Compression_ratio"> <div class="vector-toc-text"> <span class="vector-toc-numb">4.2</span> <span>Compression ratio</span> </div> </a> <ul id="toc-Compression_ratio-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Transcoding_and_editing" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Transcoding_and_editing"> <div class="vector-toc-text"> <span class="vector-toc-numb">5</span> <span>Transcoding and editing</span> </div> </a> <button aria-controls="toc-Transcoding_and_editing-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> <span class="vector-icon mw-ui-icon-wikimedia-expand"></span> <span>Toggle Transcoding and editing subsection</span> </button> <ul id="toc-Transcoding_and_editing-sublist" class="vector-toc-list"> <li id="toc-Editing_of_lossy_files" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Editing_of_lossy_files"> <div class="vector-toc-text"> <span class="vector-toc-numb">5.1</span> <span>Editing of lossy files</span> </div> </a> <ul id="toc-Editing_of_lossy_files-sublist" class="vector-toc-list"> <li id="toc-JPEG" class="vector-toc-list-item vector-toc-level-3"> <a class="vector-toc-link" href="#JPEG"> <div class="vector-toc-text"> <span class="vector-toc-numb">5.1.1</span> <span>JPEG</span> </div> </a> <ul id="toc-JPEG-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Metadata" class="vector-toc-list-item vector-toc-level-3"> <a class="vector-toc-link" href="#Metadata"> <div class="vector-toc-text"> <span class="vector-toc-numb">5.1.2</span> <span>Metadata</span> </div> </a> <ul id="toc-Metadata-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Downsampling/compressed_representation_scalability" class="vector-toc-list-item vector-toc-level-3"> <a class="vector-toc-link" href="#Downsampling/compressed_representation_scalability"> <div class="vector-toc-text"> <span class="vector-toc-numb">5.1.3</span> <span>Downsampling/compressed representation scalability</span> </div> </a> <ul id="toc-Downsampling/compressed_representation_scalability-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> </ul> </li> <li id="toc-Methods" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Methods"> <div class="vector-toc-text"> <span class="vector-toc-numb">6</span> <span>Methods</span> </div> </a> <button aria-controls="toc-Methods-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> <span class="vector-icon mw-ui-icon-wikimedia-expand"></span> <span>Toggle Methods subsection</span> </button> <ul id="toc-Methods-sublist" class="vector-toc-list"> <li id="toc-Graphics" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Graphics"> <div class="vector-toc-text"> <span class="vector-toc-numb">6.1</span> <span>Graphics</span> </div> </a> <ul id="toc-Graphics-sublist" class="vector-toc-list"> <li id="toc-Image" class="vector-toc-list-item vector-toc-level-3"> <a class="vector-toc-link" href="#Image"> <div class="vector-toc-text"> <span class="vector-toc-numb">6.1.1</span> <span>Image</span> </div> </a> <ul id="toc-Image-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-3D_computer_graphics" class="vector-toc-list-item vector-toc-level-3"> <a class="vector-toc-link" href="#3D_computer_graphics"> <div class="vector-toc-text"> <span class="vector-toc-numb">6.1.2</span> <span>3D computer graphics</span> </div> </a> <ul id="toc-3D_computer_graphics-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Video" class="vector-toc-list-item vector-toc-level-3"> <a class="vector-toc-link" href="#Video"> <div class="vector-toc-text"> <span class="vector-toc-numb">6.1.3</span> <span>Video</span> </div> </a> <ul id="toc-Video-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Audio" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Audio"> <div class="vector-toc-text"> <span class="vector-toc-numb">6.2</span> <span>Audio</span> </div> </a> <ul id="toc-Audio-sublist" class="vector-toc-list"> <li id="toc-General" class="vector-toc-list-item vector-toc-level-3"> <a class="vector-toc-link" href="#General"> <div class="vector-toc-text"> <span class="vector-toc-numb">6.2.1</span> <span>General</span> </div> </a> <ul id="toc-General-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Speech" class="vector-toc-list-item vector-toc-level-3"> <a class="vector-toc-link" href="#Speech"> <div class="vector-toc-text"> <span class="vector-toc-numb">6.2.2</span> <span>Speech</span> </div> </a> <ul id="toc-Speech-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Other_data" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Other_data"> <div class="vector-toc-text"> <span class="vector-toc-numb">6.3</span> <span>Other data</span> </div> </a> <ul id="toc-Other_data-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Lowering_resolution" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Lowering_resolution"> <div class="vector-toc-text"> <span class="vector-toc-numb">7</span> <span>Lowering resolution</span> </div> </a> <ul id="toc-Lowering_resolution-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">8</span> <span>See also</span> </div> </a> <ul id="toc-See_also-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Notes" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Notes"> <div class="vector-toc-text"> <span class="vector-toc-numb">9</span> <span>Notes</span> </div> </a> <ul id="toc-Notes-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">10</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" > <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">Lossy compression</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 31 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-31" 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">31 languages</span> </label> <div class="vector-dropdown-content"> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li class="interlanguage-link interwiki-ar mw-list-item"><a href="https://ar.wikipedia.org/wiki/%D8%B6%D8%BA%D8%B7_%D8%B0%D9%88_%D8%AE%D8%B3%D8%A7%D8%B1%D8%A9" title="ضغط ذو خسارة – Arabic" lang="ar" hreflang="ar" data-title="ضغط ذو خسارة" data-language-autonym="العربية" data-language-local-name="Arabic" class="interlanguage-link-target"><span>العربية</span></a></li><li class="interlanguage-link interwiki-ca mw-list-item"><a href="https://ca.wikipedia.org/wiki/Algorisme_de_compressi%C3%B3_amb_p%C3%A8rdua" title="Algorisme de compressió amb pèrdua – Catalan" lang="ca" hreflang="ca" data-title="Algorisme de compressió amb pèrdua" data-language-autonym="Català" data-language-local-name="Catalan" class="interlanguage-link-target"><span>Català</span></a></li><li class="interlanguage-link interwiki-cs mw-list-item"><a href="https://cs.wikipedia.org/wiki/Ztr%C3%A1tov%C3%A1_komprese" title="Ztrátová komprese – Czech" lang="cs" hreflang="cs" data-title="Ztrátová komprese" data-language-autonym="Čeština" data-language-local-name="Czech" class="interlanguage-link-target"><span>Čeština</span></a></li><li class="interlanguage-link interwiki-et mw-list-item"><a href="https://et.wikipedia.org/wiki/Kadudega_pakkimine" title="Kadudega pakkimine – Estonian" lang="et" hreflang="et" data-title="Kadudega pakkimine" data-language-autonym="Eesti" data-language-local-name="Estonian" class="interlanguage-link-target"><span>Eesti</span></a></li><li class="interlanguage-link interwiki-es mw-list-item"><a href="https://es.wikipedia.org/wiki/Algoritmo_de_compresi%C3%B3n_con_p%C3%A9rdida" title="Algoritmo de compresión con pérdida – Spanish" lang="es" hreflang="es" data-title="Algoritmo de compresión con pérdida" data-language-autonym="Español" data-language-local-name="Spanish" class="interlanguage-link-target"><span>Español</span></a></li><li class="interlanguage-link interwiki-eo mw-list-item"><a href="https://eo.wikipedia.org/wiki/Perda_datumkompaktigo" title="Perda datumkompaktigo – Esperanto" lang="eo" hreflang="eo" data-title="Perda datumkompaktigo" data-language-autonym="Esperanto" data-language-local-name="Esperanto" class="interlanguage-link-target"><span>Esperanto</span></a></li><li class="interlanguage-link interwiki-eu mw-list-item"><a href="https://eu.wikipedia.org/wiki/Galeradun_konpresio" title="Galeradun konpresio – Basque" lang="eu" hreflang="eu" data-title="Galeradun konpresio" data-language-autonym="Euskara" data-language-local-name="Basque" class="interlanguage-link-target"><span>Euskara</span></a></li><li class="interlanguage-link interwiki-fa mw-list-item"><a href="https://fa.wikipedia.org/wiki/%D9%81%D8%B4%D8%B1%D8%AF%D9%87%E2%80%8C%D8%B3%D8%A7%D8%B2%DB%8C_%D8%A8%D8%A7%D8%A7%D8%AA%D9%84%D8%A7%D9%81" title="فشرده‌سازی بااتلاف – Persian" lang="fa" hreflang="fa" data-title="فشرده‌سازی بااتلاف" data-language-autonym="فارسی" data-language-local-name="Persian" class="interlanguage-link-target"><span>فارسی</span></a></li><li class="interlanguage-link interwiki-fr mw-list-item"><a href="https://fr.wikipedia.org/wiki/Compression_de_donn%C3%A9es#Compression_avec_pertes" title="Compression de données – French" lang="fr" hreflang="fr" data-title="Compression de données" data-language-autonym="Français" data-language-local-name="French" class="interlanguage-link-target"><span>Français</span></a></li><li class="interlanguage-link interwiki-gl mw-list-item"><a href="https://gl.wikipedia.org/wiki/Algoritmo_de_compresi%C3%B3n_con_perda" title="Algoritmo de compresión con perda – Galician" lang="gl" hreflang="gl" data-title="Algoritmo de compresión con perda" data-language-autonym="Galego" data-language-local-name="Galician" class="interlanguage-link-target"><span>Galego</span></a></li><li class="interlanguage-link interwiki-ko mw-list-item"><a href="https://ko.wikipedia.org/wiki/%EC%86%90%EC%8B%A4_%EC%95%95%EC%B6%95" title="손실 압축 – Korean" lang="ko" hreflang="ko" data-title="손실 압축" data-language-autonym="한국어" data-language-local-name="Korean" class="interlanguage-link-target"><span>한국어</span></a></li><li class="interlanguage-link interwiki-hr mw-list-item"><a href="https://hr.wikipedia.org/wiki/Sa%C5%BEimanje_podataka_s_gubitcima" title="Sažimanje podataka s gubitcima – Croatian" lang="hr" hreflang="hr" data-title="Sažimanje podataka s gubitcima" data-language-autonym="Hrvatski" data-language-local-name="Croatian" class="interlanguage-link-target"><span>Hrvatski</span></a></li><li class="interlanguage-link interwiki-id mw-list-item"><a href="https://id.wikipedia.org/wiki/Kompresi_lesap" title="Kompresi lesap – Indonesian" lang="id" hreflang="id" data-title="Kompresi lesap" data-language-autonym="Bahasa Indonesia" data-language-local-name="Indonesian" class="interlanguage-link-target"><span>Bahasa Indonesia</span></a></li><li class="interlanguage-link interwiki-it mw-list-item"><a href="https://it.wikipedia.org/wiki/Compressione_dati_lossy" title="Compressione dati lossy – Italian" lang="it" hreflang="it" data-title="Compressione dati lossy" data-language-autonym="Italiano" data-language-local-name="Italian" class="interlanguage-link-target"><span>Italiano</span></a></li><li class="interlanguage-link interwiki-he mw-list-item"><a href="https://he.wikipedia.org/wiki/%D7%93%D7%97%D7%99%D7%A1%D7%94_%D7%9E%D7%90%D7%91%D7%93%D7%AA_%D7%A0%D7%AA%D7%95%D7%A0%D7%99%D7%9D" title="דחיסה מאבדת נתונים – Hebrew" lang="he" hreflang="he" data-title="דחיסה מאבדת נתונים" data-language-autonym="עברית" data-language-local-name="Hebrew" class="interlanguage-link-target"><span>עברית</span></a></li><li class="interlanguage-link interwiki-la mw-list-item"><a href="https://la.wikipedia.org/wiki/Compressio_damnosa" title="Compressio damnosa – Latin" lang="la" hreflang="la" data-title="Compressio damnosa" data-language-autonym="Latina" data-language-local-name="Latin" class="interlanguage-link-target"><span>Latina</span></a></li><li class="interlanguage-link interwiki-lv mw-list-item"><a href="https://lv.wikipedia.org/wiki/Zudumrado%C5%A1%C4%81_saspie%C5%A1ana" title="Zudumradošā saspiešana – Latvian" lang="lv" hreflang="lv" data-title="Zudumradošā saspiešana" data-language-autonym="Latviešu" data-language-local-name="Latvian" class="interlanguage-link-target"><span>Latviešu</span></a></li><li class="interlanguage-link interwiki-hu mw-list-item"><a href="https://hu.wikipedia.org/wiki/Vesztes%C3%A9ges_t%C3%B6m%C3%B6r%C3%ADt%C3%A9s" title="Veszteséges tömörítés – Hungarian" lang="hu" hreflang="hu" data-title="Veszteséges tömörítés" data-language-autonym="Magyar" data-language-local-name="Hungarian" class="interlanguage-link-target"><span>Magyar</span></a></li><li class="interlanguage-link interwiki-ja mw-list-item"><a href="https://ja.wikipedia.org/wiki/%E9%9D%9E%E5%8F%AF%E9%80%86%E5%9C%A7%E7%B8%AE" title="非可逆圧縮 – Japanese" lang="ja" hreflang="ja" data-title="非可逆圧縮" 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-no mw-list-item"><a href="https://no.wikipedia.org/wiki/Destruktiv_komprimering" title="Destruktiv komprimering – Norwegian Bokmål" lang="nb" hreflang="nb" data-title="Destruktiv komprimering" data-language-autonym="Norsk bokmål" data-language-local-name="Norwegian Bokmål" class="interlanguage-link-target"><span>Norsk bokmål</span></a></li><li class="interlanguage-link interwiki-pl mw-list-item"><a href="https://pl.wikipedia.org/wiki/Kompresja_stratna" title="Kompresja stratna – Polish" lang="pl" hreflang="pl" data-title="Kompresja stratna" data-language-autonym="Polski" data-language-local-name="Polish" class="interlanguage-link-target"><span>Polski</span></a></li><li class="interlanguage-link interwiki-pt mw-list-item"><a href="https://pt.wikipedia.org/wiki/Compress%C3%A3o_com_perda_de_dados" title="Compressão com perda de dados – Portuguese" lang="pt" hreflang="pt" data-title="Compressão com perda de dados" data-language-autonym="Português" data-language-local-name="Portuguese" class="interlanguage-link-target"><span>Português</span></a></li><li class="interlanguage-link interwiki-ru mw-list-item"><a href="https://ru.wikipedia.org/wiki/%D0%A1%D0%B6%D0%B0%D1%82%D0%B8%D0%B5_%D1%81_%D0%BF%D0%BE%D1%82%D0%B5%D1%80%D1%8F%D0%BC%D0%B8" title="Сжатие с потерями – Russian" lang="ru" hreflang="ru" data-title="Сжатие с потерями" data-language-autonym="Русский" data-language-local-name="Russian" class="interlanguage-link-target"><span>Русский</span></a></li><li class="interlanguage-link interwiki-simple mw-list-item"><a href="https://simple.wikipedia.org/wiki/Lossy_compression" title="Lossy compression – Simple English" lang="en-simple" hreflang="en-simple" data-title="Lossy compression" data-language-autonym="Simple English" data-language-local-name="Simple English" class="interlanguage-link-target"><span>Simple English</span></a></li><li class="interlanguage-link interwiki-sk mw-list-item"><a href="https://sk.wikipedia.org/wiki/Stratov%C3%A1_kompresia" title="Stratová kompresia – Slovak" lang="sk" hreflang="sk" data-title="Stratová kompresia" data-language-autonym="Slovenčina" data-language-local-name="Slovak" class="interlanguage-link-target"><span>Slovenčina</span></a></li><li class="interlanguage-link interwiki-sr mw-list-item"><a href="https://sr.wikipedia.org/wiki/%D0%9A%D0%BE%D0%BC%D0%BF%D1%80%D0%B5%D1%81%D0%B8%D1%98%D0%B0_%D1%81%D0%B0_%D0%B3%D1%83%D0%B1%D0%B8%D1%82%D0%BA%D0%BE%D0%BC" title="Компресија са губитком – Serbian" lang="sr" hreflang="sr" data-title="Компресија са губитком" data-language-autonym="Српски / srpski" data-language-local-name="Serbian" class="interlanguage-link-target"><span>Српски / srpski</span></a></li><li class="interlanguage-link interwiki-fi mw-list-item"><a href="https://fi.wikipedia.org/wiki/H%C3%A4vi%C3%B6llinen_pakkausmenetelm%C3%A4" title="Häviöllinen pakkausmenetelmä – Finnish" lang="fi" hreflang="fi" data-title="Häviöllinen pakkausmenetelmä" data-language-autonym="Suomi" data-language-local-name="Finnish" class="interlanguage-link-target"><span>Suomi</span></a></li><li class="interlanguage-link interwiki-sv mw-list-item"><a href="https://sv.wikipedia.org/wiki/Destruktiv_komprimering" title="Destruktiv komprimering – Swedish" lang="sv" hreflang="sv" data-title="Destruktiv komprimering" data-language-autonym="Svenska" data-language-local-name="Swedish" class="interlanguage-link-target"><span>Svenska</span></a></li><li class="interlanguage-link interwiki-uk mw-list-item"><a href="https://uk.wikipedia.org/wiki/%D0%A1%D1%82%D0%B8%D1%81%D0%BD%D0%B5%D0%BD%D0%BD%D1%8F_%D0%B7_%D1%83%D1%82%D1%80%D0%B0%D1%82%D0%B0%D0%BC%D0%B8" title="Стиснення з утратами – Ukrainian" lang="uk" hreflang="uk" data-title="Стиснення з утратами" data-language-autonym="Українська" data-language-local-name="Ukrainian" class="interlanguage-link-target"><span>Українська</span></a></li><li class="interlanguage-link interwiki-vi mw-list-item"><a href="https://vi.wikipedia.org/wiki/N%C3%A9n_c%C3%B3_t%E1%BB%95n_hao" title="Nén có tổn hao – Vietnamese" lang="vi" hreflang="vi" data-title="Nén có tổn hao" data-language-autonym="Tiếng Việt" data-language-local-name="Vietnamese" class="interlanguage-link-target"><span>Tiếng Việt</span></a></li><li class="interlanguage-link interwiki-zh mw-list-item"><a href="https://zh.wikipedia.org/wiki/%E6%9C%89%E6%8D%9F%E6%95%B0%E6%8D%AE%E5%8E%8B%E7%BC%A9" title="有损数据压缩 – Chinese" lang="zh" hreflang="zh" data-title="有损数据压缩" 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/Q55564#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/Lossy_compression" 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:Lossy_compression" 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/Lossy_compression"><span>Read</span></a></li><li id="ca-edit" class="vector-tab-noicon mw-list-item"><a href="/w/index.php?title=Lossy_compression&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=Lossy_compression&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/Lossy_compression"><span>Read</span></a></li><li id="ca-more-edit" class="vector-more-collapsible-item mw-list-item"><a href="/w/index.php?title=Lossy_compression&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=Lossy_compression&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/Lossy_compression" 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/Lossy_compression" 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="/wiki/Wikipedia:File_Upload_Wizard" title="Upload files [u]" accesskey="u"><span>Upload file</span></a></li><li id="t-specialpages" class="mw-list-item"><a href="/wiki/Special:SpecialPages" title="A list of all special pages [q]" accesskey="q"><span>Special pages</span></a></li><li id="t-permalink" class="mw-list-item"><a href="/w/index.php?title=Lossy_compression&oldid=1254927363" 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=Lossy_compression&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=Lossy_compression&id=1254927363&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%2FLossy_compression"><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%2FLossy_compression"><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=Lossy_compression&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=Lossy_compression&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 class="wb-otherproject-link wb-otherproject-commons mw-list-item"><a href="https://commons.wikimedia.org/wiki/Category:Lossy_compression_algorithms" hreflang="en"><span>Wikimedia Commons</span></a></li><li id="t-wikibase" class="wb-otherproject-link wb-otherproject-wikibase-dataitem mw-list-item"><a href="https://www.wikidata.org/wiki/Special:EntityPage/Q55564" 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">Data compression approach that reduces data size while discarding or changing some of it</div> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Comparison_of_JPEG_and_PNG.png" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/a/a4/Comparison_of_JPEG_and_PNG.png" decoding="async" width="200" height="200" class="mw-file-element" data-file-width="200" data-file-height="200" /></a><figcaption>Composite image showing JPG and PNG image compression. Left side of the image is from a low-quality JPEG image, showing lossy artefacts; the right side is from a PNG image.</figcaption></figure> <p>In <a href="/wiki/Information_technology" title="Information technology">information technology</a>, <b>lossy compression</b> or <b>irreversible compression</b> is the class of <a href="/wiki/Data_compression" title="Data compression">data compression</a> methods that uses inexact approximations and partial data discarding to represent the content. These techniques are used to reduce data size for storing, handling, and transmitting content. Higher degrees of approximation create coarser images as more details are removed. This is opposed to <a href="/wiki/Lossless_compression" title="Lossless compression">lossless data compression</a> (reversible data compression) which does not degrade the data. The amount of data reduction possible using lossy compression is much higher than using lossless techniques. </p><p>Well-designed lossy compression technology often reduces file sizes significantly before degradation is noticed by the end-user. Even when noticeable by the user, further data reduction may be desirable (e.g., for real-time communication or to reduce transmission times or storage needs). The most widely used lossy compression algorithm is the <a href="/wiki/Discrete_cosine_transform" title="Discrete cosine transform">discrete cosine transform</a> (DCT), first published by <a href="/wiki/N._Ahmed" class="mw-redirect" title="N. Ahmed">Nasir Ahmed</a>, T. Natarajan and <a href="/wiki/K._R._Rao" title="K. R. Rao">K. R. Rao</a> in 1974. </p><p>Lossy compression is most commonly used to compress <a href="/wiki/Multimedia" title="Multimedia">multimedia</a> data (<a href="/wiki/Sound_recording_and_reproduction" title="Sound recording and reproduction">audio</a>, <a href="/wiki/Video" title="Video">video</a>, and <a href="/wiki/Image" title="Image">images</a>), especially in applications such as <a href="/wiki/Streaming_media" title="Streaming media">streaming media</a> and <a href="/wiki/VOIP" class="mw-redirect" title="VOIP">internet telephony</a>. By contrast, lossless compression is typically required for text and data files, such as bank records and text articles. It can be advantageous to make a <a href="/wiki/Master_recording" class="mw-redirect" title="Master recording">master lossless file</a> which can then be used to produce additional copies from. This allows one to avoid basing new compressed copies off of a lossy source file, which would yield additional artifacts and further unnecessary <a class="mw-selflink-fragment" href="#Information_loss">information loss</a>. </p> <meta property="mw:PageProp/toc" /> <div class="mw-heading mw-heading2"><h2 id="Types">Types</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Lossy_compression&action=edit&section=1" title="Edit section: Types"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>It is possible to compress many types of digital data in a way that reduces the size of a <a href="/wiki/Computer_file" title="Computer file">computer file</a> needed to store it, or the <a href="/wiki/Bandwidth_(computing)" title="Bandwidth (computing)">bandwidth</a> needed to transmit it, with no loss of the full information contained in the original file. A picture, for example, is converted to a digital file by considering it to be an array of dots and specifying the color and brightness of each dot. If the picture contains an area of the same color, it can be compressed without loss by saying "200 red dots" instead of "red dot, red dot, ...(197 more times)..., red dot." </p><p>The original data contains a certain amount of information, and there is a lower bound to the size of a file that can still carry all the information. Basic <a href="/wiki/Information_theory" title="Information theory">information theory</a> says that there is an absolute limit in reducing the size of this data. When data is compressed, its <a href="/wiki/Entropy_(information_theory)" title="Entropy (information theory)">entropy</a> increases, and it cannot increase indefinitely. For example, a compressed <a href="/wiki/ZIP_(file_format)" title="ZIP (file format)">ZIP</a> file is smaller than its original, but repeatedly compressing the same file will not reduce the size to nothing. Most compression algorithms can recognize when further compression would be pointless and would in fact increase the size of the data. </p><p>In many cases, files or data streams contain more information than is needed. For example, a picture may have more detail than the eye can distinguish when reproduced at the largest size intended; likewise, an audio file does not need a lot of fine detail during a very loud passage. Developing lossy compression techniques as closely matched to human perception as possible is a complex task. Sometimes the ideal is a file that provides exactly the same perception as the original, with as much digital information as possible removed; other times, perceptible loss of quality is considered a valid tradeoff. </p><p>The terms "irreversible" and "reversible" are preferred over "lossy" and "lossless" respectively for some applications, such as medical image compression, to circumvent the negative implications of "loss". The type and amount of loss can affect the utility of the images. Artifacts or undesirable effects of compression may be clearly discernible yet the result still useful for the intended purpose. Or lossy compressed images may be '<a href="/wiki/Visually_lossless" class="mw-redirect" title="Visually lossless">visually lossless</a>', or in the case of medical images, so-called <a href="/wiki/Diagnostically_acceptable_irreversible_compression" title="Diagnostically acceptable irreversible compression">diagnostically acceptable irreversible compression</a> (DAIC)<sup id="cite_ref-1" class="reference"><a href="#cite_note-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> may have been applied. </p> <div class="mw-heading mw-heading2"><h2 id="Transform_coding">Transform coding</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Lossy_compression&action=edit&section=2" title="Edit section: Transform coding"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></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">Main article: <a href="/wiki/Transform_coding" title="Transform coding">Transform coding</a></div> <p>Some forms of lossy compression can be thought of as an application of <a href="/wiki/Transform_coding" title="Transform coding">transform coding</a>, which is a type of data compression used for <a href="/wiki/Digital_images" class="mw-redirect" title="Digital images">digital images</a>, <a href="/wiki/Digital_audio" title="Digital audio">digital audio</a> <a href="/wiki/Signal_(information_theory)" class="mw-redirect" title="Signal (information theory)">signals</a>, and <a href="/wiki/Digital_video" title="Digital video">digital video</a>. The transformation is typically used to enable better (more targeted) <a href="/wiki/Quantization_(signal_processing)" title="Quantization (signal processing)">quantization</a>. Knowledge of the application is used to choose information to discard, thereby lowering its <a href="/wiki/Bandwidth_(computing)" title="Bandwidth (computing)">bandwidth</a>. The remaining information can then be compressed via a variety of methods. When the output is decoded, the result may not be identical to the original input, but is expected to be close enough for the purpose of the application. </p><p>The most common form of lossy compression is a transform coding method, the <a href="/wiki/Discrete_cosine_transform" title="Discrete cosine transform">discrete cosine transform</a> (DCT),<sup id="cite_ref-2" class="reference"><a href="#cite_note-2"><span class="cite-bracket">[</span>2<span class="cite-bracket">]</span></a></sup> which was first published by <a href="/wiki/N._Ahmed" class="mw-redirect" title="N. Ahmed">Nasir Ahmed</a>, T. Natarajan and <a href="/wiki/K._R._Rao" title="K. R. Rao">K. R. Rao</a> in 1974.<sup id="cite_ref-pubDCT_3-0" class="reference"><a href="#cite_note-pubDCT-3"><span class="cite-bracket">[</span>3<span class="cite-bracket">]</span></a></sup> DCT is the most widely used form of lossy compression, for popular <a href="/wiki/Image_compression" title="Image compression">image compression</a> formats (such as <a href="/wiki/JPEG" title="JPEG">JPEG</a>),<sup id="cite_ref-4" class="reference"><a href="#cite_note-4"><span class="cite-bracket">[</span>4<span class="cite-bracket">]</span></a></sup> <a href="/wiki/Video_coding_standards" class="mw-redirect" title="Video coding standards">video coding standards</a> (such as <a href="/wiki/MPEG" class="mw-redirect" title="MPEG">MPEG</a> and <a href="/wiki/H.264/AVC" class="mw-redirect" title="H.264/AVC">H.264/AVC</a>) and <a href="/wiki/Audio_compression_(data)" class="mw-redirect" title="Audio compression (data)">audio compression</a> formats (such as <a href="/wiki/MP3" title="MP3">MP3</a> and <a href="/wiki/Advanced_Audio_Codec" class="mw-redirect" title="Advanced Audio Codec">AAC</a>). </p><p>In the case of audio data, a popular form of transform coding is <a href="/wiki/Perceptual_coding" class="mw-redirect" title="Perceptual coding">perceptual coding</a>, which transforms the raw data to a domain that more accurately reflects the information content. For example, rather than expressing a sound file as the amplitude levels over time, one may express it as the frequency spectrum over time, which corresponds more accurately to human audio perception. While data reduction (compression, be it lossy or lossless) is a main goal of transform coding, it also allows other goals: one may represent data more accurately for the original amount of space<sup id="cite_ref-5" class="reference"><a href="#cite_note-5"><span class="cite-bracket">[</span>5<span class="cite-bracket">]</span></a></sup> – for example, in principle, if one starts with an analog or high-resolution <a href="/wiki/Digital_master" title="Digital master">digital master</a>, an <a href="/wiki/MP3" title="MP3">MP3</a> file of a given size should provide a better representation than a raw uncompressed audio in <a href="/wiki/WAV" title="WAV">WAV</a> or <a href="/wiki/Audio_Interchange_File_Format" title="Audio Interchange File Format">AIFF</a> file of the same size. This is because uncompressed audio can only reduce file size by lowering bit rate or depth, whereas compressing audio can reduce size while maintaining bit rate and depth. This compression becomes a selective loss of the least significant data, rather than losing data across the board. Further, a transform coding may provide a better domain for manipulating or otherwise editing the data – for example, <a href="/wiki/Equalization_(audio)" title="Equalization (audio)">equalization</a> of audio is most naturally expressed in the frequency domain (boost the bass, for instance) rather than in the raw time domain. </p><p>From this point of view, perceptual encoding is not essentially about <i>discarding</i> data, but rather about a <i>better representation</i> of data. Another use is for <a href="/wiki/Backward_compatibility" title="Backward compatibility">backward compatibility</a> and <a href="/wiki/Graceful_degradation" class="mw-redirect" title="Graceful degradation">graceful degradation</a>: in color television, encoding color via a <a href="/wiki/Luminance_(video)" class="mw-redirect" title="Luminance (video)">luminance</a>-<a href="/wiki/Chrominance" title="Chrominance">chrominance</a> transform domain (such as <a href="/wiki/YUV" class="mw-redirect" title="YUV">YUV</a>) means that black-and-white sets display the luminance, while ignoring the color information. Another example is <a href="/wiki/Chroma_subsampling" title="Chroma subsampling">chroma subsampling</a>: the use of <a href="/wiki/Color_space" title="Color space">color spaces</a> such as <a href="/wiki/YIQ" title="YIQ">YIQ</a>, used in <a href="/wiki/NTSC" title="NTSC">NTSC</a>, allow one to reduce the resolution on the components to accord with human perception – humans have highest resolution for black-and-white (luma), lower resolution for mid-spectrum colors like yellow and green, and lowest for red and blues – thus NTSC displays approximately 350 pixels of luma per <a href="/wiki/Scanline" class="mw-redirect" title="Scanline">scanline</a>, 150 pixels of yellow vs. green, and 50 pixels of blue vs. red, which are proportional to human sensitivity to each component. </p> <div class="mw-heading mw-heading2"><h2 id="Information_loss">Information loss</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Lossy_compression&action=edit&section=3" title="Edit section: Information loss"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Lossy compression formats suffer from <a href="/wiki/Generation_loss" title="Generation loss">generation loss</a>: repeatedly compressing and decompressing the file will cause it to progressively lose quality. This is in contrast with <a href="/wiki/Lossless_data_compression" class="mw-redirect" title="Lossless data compression">lossless data compression</a>, where data will not be lost via the use of such a procedure. <a href="/wiki/Information_theory" title="Information theory">Information-theoretical</a> foundations for lossy data compression are provided by <a href="/wiki/Rate-distortion_theory" class="mw-redirect" title="Rate-distortion theory">rate-distortion theory</a>. Much like the use of <a href="/wiki/Probability" title="Probability">probability</a> in optimal <a href="/wiki/Coding_theory" title="Coding theory">coding theory</a>, rate-distortion theory heavily draws on <a href="/wiki/Bayesian_theory" class="mw-redirect" title="Bayesian theory">Bayesian</a> <a href="/wiki/Estimation_theory" title="Estimation theory">estimation</a> and <a href="/wiki/Decision_theory" title="Decision theory">decision theory</a> in order to model perceptual distortion and even <a href="/wiki/Aesthetic" class="mw-redirect" title="Aesthetic">aesthetic</a> judgment. </p><p>There are two basic lossy compression schemes: </p> <ul><li>In <i>lossy transform <a href="/wiki/Codec" title="Codec">codecs</a></i>, samples of picture or sound are taken, chopped into small segments, transformed into a new <a href="/wiki/Basis_(linear_algebra)" title="Basis (linear algebra)">basis space</a>, and <a href="/wiki/Quantization_(signal_processing)" title="Quantization (signal processing)">quantized</a>. The resulting quantized values are then <a href="/wiki/Entropy_encoding" class="mw-redirect" title="Entropy encoding">entropy coded</a>.</li> <li>In <i>lossy predictive codecs</i>, previous and/or subsequent decoded data is used to predict the current sound sample or image frame. The error between the predicted data and the real data, together with any extra information needed to reproduce the prediction, is then <a href="/wiki/Quantization_(signal_processing)" title="Quantization (signal processing)">quantized</a> and coded.</li></ul> <p>In some systems the two techniques are combined, with transform codecs being used to compress the error signals generated by the predictive stage. </p> <div class="mw-heading mw-heading2"><h2 id="Comparison">Comparison</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Lossy_compression&action=edit&section=4" title="Edit section: Comparison"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The advantage of lossy methods over <a href="/wiki/Lossless_compression" title="Lossless compression">lossless</a> methods is that in some cases a lossy method can produce a much smaller compressed file than any lossless method, while still meeting the requirements of the application. Lossy methods are most often used for compressing sound, images or videos. This is because these types of data are intended for human interpretation where the mind can easily "fill in the blanks" or see past very minor errors or inconsistencies – ideally lossy compression is <a href="/wiki/Transparency_(data_compression)" title="Transparency (data compression)">transparent</a> (imperceptible), which can be verified via an <a href="/wiki/ABX_test" title="ABX test">ABX test</a>. Data files using lossy compression are smaller in size and thus cost less to store and to transmit over the Internet, a crucial consideration for <a href="/wiki/Streaming_video" class="mw-redirect" title="Streaming video">streaming video</a> services such as <a href="/wiki/Netflix" title="Netflix">Netflix</a> and <a href="/wiki/Streaming_audio" class="mw-redirect" title="Streaming audio">streaming audio</a> services such as <a href="/wiki/Spotify" title="Spotify">Spotify</a>. </p> <div class="mw-heading mw-heading3"><h3 id="Transparency">Transparency</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Lossy_compression&action=edit&section=5" title="Edit section: Transparency"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">Further information: <a href="/wiki/Transparency_(data_compression)" title="Transparency (data compression)">Transparency (data compression)</a></div> <p>When a user acquires a lossily compressed file, (for example, to reduce download time) the retrieved file can be quite different from the original at the <a href="/wiki/Bit" title="Bit">bit</a> level while being indistinguishable to the human ear or eye for most practical purposes. Many compression methods focus on the idiosyncrasies of <a href="/wiki/Human_physiology" class="mw-redirect" title="Human physiology">human physiology</a>, taking into account, for instance, that the human eye can see only certain wavelengths of light. The <a href="/wiki/Psychoacoustic_model" class="mw-redirect" title="Psychoacoustic model">psychoacoustic model</a> describes how sound can be highly compressed without degrading perceived quality. Flaws caused by lossy compression that are noticeable to the human eye or ear are known as <a href="/wiki/Compression_artifact" title="Compression artifact">compression artifacts</a>. </p> <div class="mw-heading mw-heading3"><h3 id="Compression_ratio">Compression ratio</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Lossy_compression&action=edit&section=6" title="Edit section: Compression ratio"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The <a href="/wiki/Data_compression_ratio" title="Data compression ratio">compression ratio</a> (that is, the size of the compressed file compared to that of the uncompressed file) of lossy video codecs is nearly always far superior to that of the audio and still-image equivalents. </p> <ul><li>Video can be compressed immensely (e.g., 100:1) with little visible quality loss</li> <li>Audio can often be compressed at 10:1 with almost imperceptible loss of quality</li> <li>Still images are often lossily compressed at 10:1, as with audio, but the quality loss is more noticeable, especially on closer inspection.</li></ul> <div class="mw-heading mw-heading2"><h2 id="Transcoding_and_editing">Transcoding and editing</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Lossy_compression&action=edit&section=7" title="Edit section: Transcoding and editing"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">Further information: <a href="/wiki/Transcoding" title="Transcoding">Transcoding</a></div> <p>An important caveat about lossy compression (formally transcoding), is that editing lossily compressed files causes <a href="/wiki/Digital_generation_loss" class="mw-redirect" title="Digital generation loss">digital generation loss</a> from the re-encoding. This can be avoided by only producing lossy files from (lossless) originals and only editing (copies of) original files, such as images in <a href="/wiki/Raw_image_format" title="Raw image format">raw image format</a> instead of <a href="/wiki/JPEG" title="JPEG">JPEG</a>. If data which has been compressed lossily is decoded and compressed losslessly, the size of the result can be comparable with the size of the data before lossy compression, but the data already lost cannot be recovered. When deciding to use lossy conversion without keeping the original, format conversion may be needed in the future to achieve compatibility with software or devices (<a href="/wiki/Format_shifting" title="Format shifting">format shifting</a>), or to avoid paying <a href="/wiki/Software_patent" title="Software patent">patent royalties</a> for decoding or distribution of compressed files. </p> <div class="mw-heading mw-heading3"><h3 id="Editing_of_lossy_files">Editing of lossy files</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Lossy_compression&action=edit&section=8" title="Edit section: Editing of lossy files"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">See also: <a href="https://commons.wikimedia.org/wiki/Commons:Software#JPEG" class="extiw" title="commons:Commons:Software">commons:Commons:Software § JPEG</a>, and <a href="https://commons.wikimedia.org/wiki/Commons:Software#Ogg_Vorbis_(audio)" class="extiw" title="commons:Commons:Software">commons:Commons:Software § Ogg Vorbis (audio)</a></div> <p>By modifying the compressed data directly without decoding and re-encoding, some editing of lossily compressed files without degradation of quality is possible. Editing which reduces the file size as if it had been compressed to a greater degree, but without more loss than this, is sometimes also possible. </p> <div class="mw-heading mw-heading4"><h4 id="JPEG">JPEG</h4><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Lossy_compression&action=edit&section=9" title="Edit section: JPEG"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The primary programs for lossless editing of JPEGs are <code><a href="/wiki/Jpegtran" class="mw-redirect" title="Jpegtran">jpegtran</a></code>, and the derived <code>exiftran</code> (which also preserves <a href="/wiki/Exif" title="Exif">Exif</a> information), and <a rel="nofollow" class="external text" href="http://sylvana.net/jpegcrop/">Jpegcrop</a> (which provides a Windows interface). </p><p>These allow the image to be <a href="/wiki/Cropping_(image)" title="Cropping (image)">cropped</a>, rotated, <a href="/wiki/Flipped_image" title="Flipped image">flipped</a>, and <a href="/wiki/Flopped_image" title="Flopped image">flopped</a>, or even converted to <a href="/wiki/Grayscale" title="Grayscale">grayscale</a> (by dropping the <a href="/wiki/Chrominance" title="Chrominance">chrominance</a> channel). While unwanted information is destroyed, the quality of the remaining portion is unchanged. </p><p>Some other transforms are possible to some extent, such as joining images with the same encoding (composing side by side, as on a grid) or pasting images such as logos onto existing images (both via <a rel="nofollow" class="external text" href="http://sylvana.net/jpegcrop/jpegjoin/">Jpegjoin</a>), or scaling.<sup id="cite_ref-6" class="reference"><a href="#cite_note-6"><span class="cite-bracket">[</span>6<span class="cite-bracket">]</span></a></sup> </p><p>Some changes can be made to the compression without re-encoding: </p> <ul><li>Optimizing the compression (to reduce size without change to the decoded image)</li> <li>Converting between progressive and non-progressive encoding.</li></ul> <p>The freeware Windows-only <a href="/wiki/IrfanView" title="IrfanView">IrfanView</a> has some lossless JPEG operations in its <code>JPG_TRANSFORM</code> <a href="/wiki/Plug-in_(computing)" title="Plug-in (computing)">plugin</a>. </p> <div class="mw-heading mw-heading4"><h4 id="Metadata">Metadata</h4><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Lossy_compression&action=edit&section=10" title="Edit section: Metadata"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Metadata, such as <a href="/wiki/ID3_tag" class="mw-redirect" title="ID3 tag">ID3 tags</a>, <a href="/wiki/Vorbis_comment" title="Vorbis comment">Vorbis comments</a>, or <a href="/wiki/Exif" title="Exif">Exif</a> information, can usually be modified or removed without modifying the underlying data. </p> <div class="mw-heading mw-heading4"><h4 id="Downsampling/compressed_representation_scalability"><span id="Downsampling.2Fcompressed_representation_scalability"></span>Downsampling/compressed representation scalability</h4><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Lossy_compression&action=edit&section=11" title="Edit section: Downsampling/compressed representation scalability"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>One may wish to <a href="/wiki/Downsample" class="mw-redirect" title="Downsample">downsample</a> or otherwise decrease the resolution of the represented source signal and the quantity of data used for its compressed representation without re-encoding, as in <a href="/wiki/Bitrate_peeling" title="Bitrate peeling">bitrate peeling</a>, but this functionality is not supported in all designs, as not all codecs encode data in a form that allows less important detail to simply be dropped. Some well-known designs that have this capability include <a href="/wiki/JPEG_2000" title="JPEG 2000">JPEG 2000</a> for still images and <a href="/wiki/H.264/MPEG-4_AVC" class="mw-redirect" title="H.264/MPEG-4 AVC">H.264/MPEG-4 AVC</a> based <a href="/w/index.php?title=Scalable_Video_Coding&action=edit&redlink=1" class="new" title="Scalable Video Coding (page does not exist)">Scalable Video Coding</a> for video. Such schemes have also been standardized for older designs as well, such as <a href="/wiki/JPEG" title="JPEG">JPEG</a> images with progressive encoding, and <a href="/wiki/MPEG-2" title="MPEG-2">MPEG-2</a> and <a href="/wiki/MPEG-4_Part_2" title="MPEG-4 Part 2">MPEG-4 Part 2</a> video, although those prior schemes had limited success in terms of adoption into real-world common usage. Without this capacity, which is often the case in practice, to produce a representation with lower resolution or lower fidelity than a given one, one needs to start with the original source signal and encode, or start with a compressed representation and then decompress and re-encode it (<a href="/wiki/Transcoding" title="Transcoding">transcoding</a>), though the latter tends to cause <a href="/wiki/Digital_generation_loss" class="mw-redirect" title="Digital generation loss">digital generation loss</a>. </p><p>Another approach is to encode the original signal at several different bitrates, and then either choose which to use (as when streaming over the internet – as in <a href="/wiki/RealNetworks" title="RealNetworks">RealNetworks</a>' "<a href="/w/index.php?title=SureStream&action=edit&redlink=1" class="new" title="SureStream (page does not exist)">SureStream</a>" – or offering varying downloads, as at Apple's <a href="/wiki/ITunes_Store" title="ITunes Store">iTunes Store</a>), or broadcast several, where the best that is successfully received is used, as in various implementations of <a href="/wiki/Hierarchical_modulation" title="Hierarchical modulation">hierarchical modulation</a>. Similar techniques are used in <a href="/wiki/Mipmap" title="Mipmap">mipmaps</a>, <a href="/wiki/Pyramid_(image_processing)" title="Pyramid (image processing)">pyramid representations</a>, and more sophisticated <a href="/wiki/Scale_space" title="Scale space">scale space</a> methods. Some audio formats feature a combination of a lossy format and a lossless correction which when combined reproduce the original signal; the correction can be stripped, leaving a smaller, lossily compressed, file. Such formats include <a href="/wiki/MPEG-4_SLS" title="MPEG-4 SLS">MPEG-4 SLS</a> (Scalable to Lossless), <a href="/wiki/WavPack" title="WavPack">WavPack</a>, <a href="/wiki/OptimFROG_DualStream" class="mw-redirect" title="OptimFROG DualStream">OptimFROG DualStream</a>, and <a href="/wiki/DTS-HD_Master_Audio" title="DTS-HD Master Audio">DTS-HD Master Audio in lossless (XLL) mode</a>). </p> <div class="mw-heading mw-heading2"><h2 id="Methods">Methods</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Lossy_compression&action=edit&section=12" title="Edit section: Methods"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <div class="mw-heading mw-heading3"><h3 id="Graphics">Graphics</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Lossy_compression&action=edit&section=13" title="Edit section: Graphics"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <div class="mw-heading mw-heading4"><h4 id="Image">Image</h4><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Lossy_compression&action=edit&section=14" title="Edit section: Image"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">Further information: <a href="/wiki/Image_compression" title="Image compression">Image compression</a></div> <ul><li><a href="/wiki/Discrete_cosine_transform" title="Discrete cosine transform">Discrete cosine transform</a> (DCT) <ul><li><a href="/wiki/JPEG" title="JPEG">JPEG</a><sup id="cite_ref-Stankovic_7-0" class="reference"><a href="#cite_note-Stankovic-7"><span class="cite-bracket">[</span>7<span class="cite-bracket">]</span></a></sup></li> <li><a href="/wiki/WebP" title="WebP">WebP</a> (high-density lossless or lossy compression of RGB and RGBA images)</li> <li><a href="/wiki/High_Efficiency_Image_Format" class="mw-redirect" title="High Efficiency Image Format">High Efficiency Image Format</a> (HEIF)</li> <li><a href="/wiki/Better_Portable_Graphics" title="Better Portable Graphics">Better Portable Graphics</a> (BPG) (lossless or lossy compression)</li> <li><a href="/wiki/JPEG_XR" title="JPEG XR">JPEG XR</a>, a successor of JPEG with support for <a href="/wiki/High-dynamic-range_imaging" class="mw-redirect" title="High-dynamic-range imaging">high-dynamic range</a>, wide <a href="/wiki/Gamut" title="Gamut">gamut</a> pixel formats (lossless or lossy compression)</li></ul></li> <li><a href="/wiki/Wavelet_compression" class="mw-redirect" title="Wavelet compression">Wavelet compression</a> <ul><li><a href="/wiki/JPEG_2000" title="JPEG 2000">JPEG 2000</a>, JPEG's successor format that uses <a href="/wiki/Wavelets" class="mw-redirect" title="Wavelets">wavelets</a> (lossless or lossy compression)</li> <li><a href="/wiki/DjVu" title="DjVu">DjVu</a></li> <li><a href="/wiki/ICER_(file_format)" title="ICER (file format)">ICER</a>, used by the Mars Rovers, related to <a href="/wiki/JPEG_2000" title="JPEG 2000">JPEG 2000</a> in its use of wavelets</li> <li><a href="/wiki/Progressive_Graphics_File" title="Progressive Graphics File">PGF</a>, Progressive Graphics File (lossless or lossy compression)</li></ul></li> <li><a href="/wiki/Cartesian_Perceptual_Compression" title="Cartesian Perceptual Compression">Cartesian Perceptual Compression</a>, also known as CPC</li> <li><a href="/wiki/Fractal_compression" title="Fractal compression">Fractal compression</a></li> <li><a href="/wiki/JBIG2" title="JBIG2">JBIG2</a> (lossless or lossy compression)</li> <li><a href="/wiki/S3TC" class="mw-redirect" title="S3TC">S3TC</a> <a href="/wiki/Texture_mapping" title="Texture mapping">texture</a> compression for <a href="/wiki/GPU" class="mw-redirect" title="GPU">3D computer graphics hardware</a></li></ul> <div class="mw-heading mw-heading4"><h4 id="3D_computer_graphics">3D computer graphics</h4><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Lossy_compression&action=edit&section=15" title="Edit section: 3D computer graphics"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li><a href="/wiki/GlTF" title="GlTF">glTF</a></li></ul> <div class="mw-heading mw-heading4"><h4 id="Video">Video</h4><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Lossy_compression&action=edit&section=16" title="Edit section: Video"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">Further information: <a href="/wiki/Video_coding_format" title="Video coding format">Video coding format</a> and <a href="/wiki/Video_compression" class="mw-redirect" title="Video compression">Video compression</a></div> <ul><li><a href="/wiki/Discrete_cosine_transform" title="Discrete cosine transform">Discrete cosine transform</a> (DCT) <ul><li><a href="/wiki/H.261" title="H.261">H.261</a><sup id="cite_ref-Stankovic_7-1" class="reference"><a href="#cite_note-Stankovic-7"><span class="cite-bracket">[</span>7<span class="cite-bracket">]</span></a></sup></li> <li><a href="/wiki/Motion_JPEG" title="Motion JPEG">Motion JPEG</a><sup id="cite_ref-Stankovic_7-2" class="reference"><a href="#cite_note-Stankovic-7"><span class="cite-bracket">[</span>7<span class="cite-bracket">]</span></a></sup></li> <li><a href="/wiki/MPEG-1_Part_2" class="mw-redirect" title="MPEG-1 Part 2">MPEG-1 Part 2</a><sup id="cite_ref-Rao_8-0" class="reference"><a href="#cite_note-Rao-8"><span class="cite-bracket">[</span>8<span class="cite-bracket">]</span></a></sup></li> <li><a href="/wiki/MPEG-2_Part_2" class="mw-redirect" title="MPEG-2 Part 2">MPEG-2 Part 2</a> (H.262)<sup id="cite_ref-Rao_8-1" class="reference"><a href="#cite_note-Rao-8"><span class="cite-bracket">[</span>8<span class="cite-bracket">]</span></a></sup></li> <li><a href="/wiki/MPEG-4_Part_2" title="MPEG-4 Part 2">MPEG-4 Part 2</a> (<a href="/wiki/H.263" title="H.263">H.263</a>)<sup id="cite_ref-Stankovic_7-3" class="reference"><a href="#cite_note-Stankovic-7"><span class="cite-bracket">[</span>7<span class="cite-bracket">]</span></a></sup></li> <li><a href="/wiki/Advanced_Video_Coding" title="Advanced Video Coding">Advanced Video Coding</a> (AVC / H.264 / <a href="/wiki/MPEG-4" title="MPEG-4">MPEG-4</a> AVC)<sup id="cite_ref-Stankovic_7-4" class="reference"><a href="#cite_note-Stankovic-7"><span class="cite-bracket">[</span>7<span class="cite-bracket">]</span></a></sup> (may also be lossless, even in certain video sections)</li> <li><a href="/wiki/High_Efficiency_Video_Coding" title="High Efficiency Video Coding">High Efficiency Video Coding</a> (HEVC / H.265)<sup id="cite_ref-Stankovic_7-5" class="reference"><a href="#cite_note-Stankovic-7"><span class="cite-bracket">[</span>7<span class="cite-bracket">]</span></a></sup></li> <li><a href="/wiki/Ogg" title="Ogg">Ogg</a> <a href="/wiki/Theora" title="Theora">Theora</a> (noted for its lack of patent restrictions)</li> <li><a href="/wiki/VC-1" title="VC-1">VC-1</a></li></ul></li> <li><a href="/wiki/Wavelet_compression" class="mw-redirect" title="Wavelet compression">Wavelet compression</a> <ul><li><a href="/wiki/Motion_JPEG_2000" title="Motion JPEG 2000">Motion JPEG 2000</a></li> <li><a href="/wiki/Dirac_codec" class="mw-redirect" title="Dirac codec">Dirac</a></li></ul></li> <li><a href="/wiki/Sorenson_codec" class="mw-redirect" title="Sorenson codec">Sorenson video codec</a></li></ul> <div class="mw-heading mw-heading3"><h3 id="Audio">Audio</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Lossy_compression&action=edit&section=17" title="Edit section: Audio"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">Further information: <a href="/wiki/Audio_coding_format" title="Audio coding format">Audio coding format</a> and <a href="/wiki/Audio_data_compression" class="mw-redirect" title="Audio data compression">Audio data compression</a></div> <div class="mw-heading mw-heading4"><h4 id="General">General</h4><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Lossy_compression&action=edit&section=18" title="Edit section: General"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li><a href="/wiki/Modified_discrete_cosine_transform" title="Modified discrete cosine transform">Modified discrete cosine transform</a> (MDCT) <ul><li><a href="/wiki/Dolby_Digital" title="Dolby Digital">Dolby Digital</a> (AC-3)</li> <li><a href="/wiki/Adaptive_Transform_Acoustic_Coding" class="mw-redirect" title="Adaptive Transform Acoustic Coding">Adaptive Transform Acoustic Coding</a> (ATRAC)</li> <li><a href="/wiki/MPEG_Layer_III" class="mw-redirect" title="MPEG Layer III">MPEG Layer III</a> (MP3)<sup id="cite_ref-Guckert_9-0" class="reference"><a href="#cite_note-Guckert-9"><span class="cite-bracket">[</span>9<span class="cite-bracket">]</span></a></sup></li> <li><a href="/wiki/Advanced_Audio_Coding" title="Advanced Audio Coding">Advanced Audio Coding</a> (AAC / <a href="/wiki/MP4" class="mw-redirect" title="MP4">MP4</a> Audio)<sup id="cite_ref-brandenburg_10-0" class="reference"><a href="#cite_note-brandenburg-10"><span class="cite-bracket">[</span>10<span class="cite-bracket">]</span></a></sup></li> <li><a href="/wiki/Vorbis" title="Vorbis">Vorbis</a></li> <li><a href="/wiki/Windows_Media_Audio" title="Windows Media Audio">Windows Media Audio</a> (WMA) (Standard and Pro profiles are lossy. WMA Lossless is also available.)</li> <li><a href="/wiki/LDAC_(codec)" title="LDAC (codec)">LDAC</a><sup id="cite_ref-Darko_2017_11-0" class="reference"><a href="#cite_note-Darko_2017-11"><span class="cite-bracket">[</span>11<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-AVHub_2015_12-0" class="reference"><a href="#cite_note-AVHub_2015-12"><span class="cite-bracket">[</span>12<span class="cite-bracket">]</span></a></sup></li> <li><a href="/wiki/Opus_(codec)" class="mw-redirect" title="Opus (codec)">Opus</a> (Notable for lack of patent restrictions, low delay, and high quality speech and general audio.)</li></ul></li> <li><a href="/wiki/Adaptive_differential_pulse-code_modulation" title="Adaptive differential pulse-code modulation">Adaptive differential pulse-code modulation</a> (ADPCM) <ul><li><a href="/wiki/Master_Quality_Authenticated" title="Master Quality Authenticated">Master Quality Authenticated</a> (MQA)</li></ul></li> <li><a href="/wiki/MPEG-1_Audio_Layer_II" title="MPEG-1 Audio Layer II">MPEG-1 Audio Layer II</a> (MP2)</li> <li><a href="/wiki/Musepack" title="Musepack">Musepack</a> (based on Musicam)</li> <li><a href="/wiki/AptX" title="AptX">aptX/ aptX-HD</a><sup id="cite_ref-AVHub_2016_13-0" class="reference"><a href="#cite_note-AVHub_2016-13"><span class="cite-bracket">[</span>13<span class="cite-bracket">]</span></a></sup></li></ul> <div class="mw-heading mw-heading4"><h4 id="Speech">Speech</h4><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Lossy_compression&action=edit&section=19" title="Edit section: Speech"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">Further information: <a href="/wiki/Speech_encoding" class="mw-redirect" title="Speech encoding">Speech encoding</a></div> <ul><li><a href="/wiki/Linear_predictive_coding" title="Linear predictive coding">Linear predictive coding</a> (LPC) <ul><li><a href="/wiki/Adaptive_predictive_coding" title="Adaptive predictive coding">Adaptive predictive coding</a> (APC)</li> <li><a href="/wiki/Code-excited_linear_prediction" title="Code-excited linear prediction">Code-excited linear prediction</a> (CELP)</li> <li><a href="/wiki/Algebraic_code-excited_linear_prediction" title="Algebraic code-excited linear prediction">Algebraic code-excited linear prediction</a> (ACELP)</li> <li><a href="/wiki/Relaxed_code-excited_linear_prediction" title="Relaxed code-excited linear prediction">Relaxed code-excited linear prediction</a> (RCELP)</li> <li><a href="/wiki/Low-delay_CELP" class="mw-redirect" title="Low-delay CELP">Low-delay CELP</a> (LD-CELP)</li> <li><a href="/wiki/Adaptive_Multi-Rate_audio_codec" title="Adaptive Multi-Rate audio codec">Adaptive Multi-Rate</a> (used in <a href="/wiki/GSM" title="GSM">GSM</a> and <a href="/wiki/3GPP" title="3GPP">3GPP</a>)</li> <li><a href="/wiki/Codec2" class="mw-redirect" title="Codec2">Codec2</a> (noted for its lack of patent restrictions)</li> <li><a href="/wiki/Speex" title="Speex">Speex</a> (noted for its lack of patent restrictions)</li></ul></li> <li><a href="/wiki/Modified_discrete_cosine_transform" title="Modified discrete cosine transform">Modified discrete cosine transform</a> (MDCT) <ul><li><a href="/wiki/AAC-LD" title="AAC-LD">AAC-LD</a></li> <li><a href="/wiki/Constrained_Energy_Lapped_Transform" class="mw-redirect" title="Constrained Energy Lapped Transform">Constrained Energy Lapped Transform</a> (CELT)</li> <li><a href="/wiki/Opus_(codec)" class="mw-redirect" title="Opus (codec)">Opus</a> (mostly for real-time applications)</li></ul></li></ul> <div class="mw-heading mw-heading3"><h3 id="Other_data">Other data</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Lossy_compression&action=edit&section=20" title="Edit section: Other data"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Researchers have performed lossy compression on text by either using a <a href="/wiki/Thesaurus" title="Thesaurus">thesaurus</a> to substitute short words for long ones, or <a href="/wiki/Natural_language_generation" title="Natural language generation">generative text</a> techniques,<sup id="cite_ref-14" class="reference"><a href="#cite_note-14"><span class="cite-bracket">[</span>14<span class="cite-bracket">]</span></a></sup> although these sometimes fall into the related category of <a href="/wiki/Lossy_data_conversion" title="Lossy data conversion">lossy data conversion</a>. </p> <div class="mw-heading mw-heading2"><h2 id="Lowering_resolution">Lowering resolution</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Lossy_compression&action=edit&section=21" title="Edit section: Lowering resolution"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>A general kind of lossy compression is to lower the resolution of an image, as in <a href="/wiki/Image_scaling" title="Image scaling">image scaling</a>, particularly <a href="/wiki/Decimation_(signal_processing)" class="mw-redirect" title="Decimation (signal processing)">decimation</a>. One may also remove less "lower information" parts of an image, such as by <a href="/wiki/Seam_carving" title="Seam carving">seam carving</a>. Many media transforms, such as <a href="/wiki/Gaussian_blur" title="Gaussian blur">Gaussian blur</a>, are, like lossy compression, irreversible: the original signal cannot be reconstructed from the transformed signal. However, in general these will have the same size as the original, and are not a form of compression. Lowering resolution has practical uses, as the <a href="/wiki/NASA" title="NASA">NASA</a> <a href="/wiki/New_Horizons" title="New Horizons">New Horizons</a> craft transmitted <a href="/wiki/Thumbnail" title="Thumbnail">thumbnails</a> of its encounter with Pluto-Charon before it sent the higher resolution images. Another solution for slow connections is the usage of <a href="/wiki/Interlacing_(bitmaps)" title="Interlacing (bitmaps)">Image interlacing</a> which progressively defines the image. Thus a partial transmission is enough to preview the final image, in a lower resolution version, without creating a scaled and a full version too.<sup class="noprint Inline-Template Template-Fact" style="white-space:nowrap;">[<i><a href="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (November 2019)">citation needed</span></a></i>]</sup> </p> <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=Lossy_compression&action=edit&section=22" title="Edit section: See also"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li><a href="/wiki/Compression_artifact" title="Compression artifact">Compression artifact</a></li> <li><a href="/wiki/Data_compression" title="Data compression">Data compression</a></li> <li><a href="/wiki/Image_scaling" title="Image scaling">Image scaling</a></li> <li><a href="/wiki/Lenna" title="Lenna">Lenna</a></li> <li><a href="/wiki/List_of_codecs" title="List of codecs">List of codecs</a></li> <li><a href="/wiki/Lossless_compression" title="Lossless compression">Lossless compression</a></li> <li><a href="/wiki/Rate%E2%80%93distortion_theory" title="Rate–distortion theory">Rate–distortion theory</a></li> <li><a href="/wiki/Seam_carving" title="Seam carving">Seam carving</a></li> <li><a href="/wiki/Transcoding" title="Transcoding">Transcoding</a></li></ul> <div class="mw-heading mw-heading2"><h2 id="Notes">Notes</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Lossy_compression&action=edit&section=23" title="Edit section: Notes"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <div class="mw-references-wrap mw-references-columns"><ol class="references"> <li id="cite_note-1"><span class="mw-cite-backlink"><b><a href="#cite_ref-1">^</a></b></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="CITEREFEuropean_Society_of_Radiology2011" class="citation journal cs1">European Society of Radiology (2011). <a rel="nofollow" class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3259360">"Usability of irreversible image compression in radiological imaging. A position paper by the European Society of Radiology (ESR)"</a>. <i>Insights Imaging</i>. <b>2</b> (2): 103–115. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1007%2Fs13244-011-0071-x">10.1007/s13244-011-0071-x</a>. <a href="/wiki/PMC_(identifier)" class="mw-redirect" title="PMC (identifier)">PMC</a> <span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3259360">3259360</a></span>. <a href="/wiki/PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/22347940">22347940</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Insights+Imaging&rft.atitle=Usability+of+irreversible+image+compression+in+radiological+imaging.+A+position+paper+by+the+European+Society+of+Radiology+%28ESR%29&rft.volume=2&rft.issue=2&rft.pages=103-115&rft.date=2011&rft_id=https%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fpmc%2Farticles%2FPMC3259360%23id-name%3DPMC&rft_id=info%3Apmid%2F22347940&rft_id=info%3Adoi%2F10.1007%2Fs13244-011-0071-x&rft.au=European+Society+of+Radiology&rft_id=https%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fpmc%2Farticles%2FPMC3259360&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALossy+compression" class="Z3988"></span></span> </li> <li id="cite_note-2"><span class="mw-cite-backlink"><b><a href="#cite_ref-2">^</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.britannica.com/technology/data-compression">"Data compression"</a>. <i><a href="/wiki/Encyclopedia_Britannica" class="mw-redirect" title="Encyclopedia Britannica">Encyclopedia Britannica</a></i><span class="reference-accessdate">. Retrieved <span class="nowrap">13 August</span> 2019</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=Encyclopedia+Britannica&rft.atitle=Data+compression&rft_id=https%3A%2F%2Fwww.britannica.com%2Ftechnology%2Fdata-compression&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALossy+compression" class="Z3988"></span></span> </li> <li id="cite_note-pubDCT-3"><span class="mw-cite-backlink"><b><a href="#cite_ref-pubDCT_3-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFAhmedNatarajanRao1974" class="citation cs2"><a href="/wiki/N._Ahmed" class="mw-redirect" title="N. Ahmed">Ahmed, Nasir</a>; Natarajan, T.; <a href="/wiki/K._R._Rao" title="K. R. Rao">Rao, K. R.</a> (January 1974), "Discrete Cosine Transform", <i>IEEE Transactions on Computers</i>, <b>C-23</b> (1): 90–93, <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%2FT-C.1974.223784">10.1109/T-C.1974.223784</a>, <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:149806273">149806273</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+Computers&rft.atitle=Discrete+Cosine+Transform&rft.volume=C-23&rft.issue=1&rft.pages=90-93&rft.date=1974-01&rft_id=info%3Adoi%2F10.1109%2FT-C.1974.223784&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A149806273%23id-name%3DS2CID&rft.aulast=Ahmed&rft.aufirst=Nasir&rft.au=Natarajan%2C+T.&rft.au=Rao%2C+K.+R.&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALossy+compression" class="Z3988"></span></span> </li> <li id="cite_note-4"><span class="mw-cite-backlink"><b><a href="#cite_ref-4">^</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.w3.org/Graphics/JPEG/itu-t81.pdf">"T.81 – DIGITAL COMPRESSION AND CODING OF CONTINUOUS-TONE STILL IMAGES – REQUIREMENTS AND GUIDELINES"</a> <span class="cs1-format">(PDF)</span>. CCITT. September 1992<span class="reference-accessdate">. Retrieved <span class="nowrap">12 July</span> 2019</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=T.81+%E2%80%93+DIGITAL+COMPRESSION+AND+CODING+OF+CONTINUOUS-TONE+STILL+IMAGES+%E2%80%93+REQUIREMENTS+AND+GUIDELINES&rft.pub=CCITT&rft.date=1992-09&rft_id=https%3A%2F%2Fwww.w3.org%2FGraphics%2FJPEG%2Fitu-t81.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALossy+compression" class="Z3988"></span></span> </li> <li id="cite_note-5"><span class="mw-cite-backlink"><b><a href="#cite_ref-5">^</a></b></span> <span class="reference-text">“Although one main goal of digital audio perceptual coders is data reduction, this is not a necessary characteristic. As we shall see, perceptual coding can be used to improve the representation of digital audio through advanced bit allocation.” <a rel="nofollow" class="external text" href="http://www.noisebetweenstations.com/personal/essays/audio_on_the_internet/MaskingPaper.html">Masking and Perceptual Coding</a>, Victor Lombardi, noisebetweenstations.com</span> </li> <li id="cite_note-6"><span class="mw-cite-backlink"><b><a href="#cite_ref-6">^</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://sylvana.net/jpegcrop/jpegtran/">"New jpegtran features"</a>. <i>sylvana.net</i><span class="reference-accessdate">. Retrieved <span class="nowrap">2019-09-20</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=sylvana.net&rft.atitle=New+jpegtran+features&rft_id=http%3A%2F%2Fsylvana.net%2Fjpegcrop%2Fjpegtran%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALossy+compression" class="Z3988"></span></span> </li> <li id="cite_note-Stankovic-7"><span class="mw-cite-backlink">^ <a href="#cite_ref-Stankovic_7-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-Stankovic_7-1"><sup><i><b>b</b></i></sup></a> <a href="#cite_ref-Stankovic_7-2"><sup><i><b>c</b></i></sup></a> <a href="#cite_ref-Stankovic_7-3"><sup><i><b>d</b></i></sup></a> <a href="#cite_ref-Stankovic_7-4"><sup><i><b>e</b></i></sup></a> <a href="#cite_ref-Stankovic_7-5"><sup><i><b>f</b></i></sup></a></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFStankovićAstola2012" class="citation journal cs1">Stanković, Radomir S.; Astola, Jaakko T. (2012). <a rel="nofollow" class="external text" href="http://ticsp.cs.tut.fi/reports/ticsp-report-60-reprint-rao-corrected.pdf">"Reminiscences of the Early Work in DCT: Interview with K.R. Rao"</a> <span class="cs1-format">(PDF)</span>. <i>Reprints from the Early Days of Information Sciences</i>. <b>60</b><span class="reference-accessdate">. Retrieved <span class="nowrap">13 October</span> 2019</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Reprints+from+the+Early+Days+of+Information+Sciences&rft.atitle=Reminiscences+of+the+Early+Work+in+DCT%3A+Interview+with+K.R.+Rao&rft.volume=60&rft.date=2012&rft.aulast=Stankovi%C4%87&rft.aufirst=Radomir+S.&rft.au=Astola%2C+Jaakko+T.&rft_id=http%3A%2F%2Fticsp.cs.tut.fi%2Freports%2Fticsp-report-60-reprint-rao-corrected.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALossy+compression" class="Z3988"></span></span> </li> <li id="cite_note-Rao-8"><span class="mw-cite-backlink">^ <a href="#cite_ref-Rao_8-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-Rao_8-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text">K. R. Rao and J. J. Hwang, <i>Techniques and Standards for Image, Video, and Audio Coding</i>, Prentice Hall, 1996; JPEG: Chapter 8; H.261: Chapter 9; MPEG-1: Chapter 10; MPEG-2: Chapter 11.</span> </li> <li id="cite_note-Guckert-9"><span class="mw-cite-backlink"><b><a href="#cite_ref-Guckert_9-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFGuckert2012" class="citation web cs1">Guckert, John (Spring 2012). <a rel="nofollow" class="external text" href="http://www.math.utah.edu/~gustafso/s2012/2270/web-projects/Guckert-audio-compression-svd-mdct-MP3.pdf">"The Use of FFT and MDCT in MP3 Audio Compression"</a> <span class="cs1-format">(PDF)</span>. <i><a href="/wiki/University_of_Utah" title="University of Utah">University of Utah</a></i><span class="reference-accessdate">. Retrieved <span class="nowrap">14 July</span> 2019</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=University+of+Utah&rft.atitle=The+Use+of+FFT+and+MDCT+in+MP3+Audio+Compression&rft.ssn=spring&rft.date=2012&rft.aulast=Guckert&rft.aufirst=John&rft_id=http%3A%2F%2Fwww.math.utah.edu%2F~gustafso%2Fs2012%2F2270%2Fweb-projects%2FGuckert-audio-compression-svd-mdct-MP3.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALossy+compression" class="Z3988"></span></span> </li> <li id="cite_note-brandenburg-10"><span class="mw-cite-backlink"><b><a href="#cite_ref-brandenburg_10-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFBrandenburg1999" class="citation web cs1">Brandenburg, Karlheinz (1999). <a rel="nofollow" class="external text" href="http://graphics.ethz.ch/teaching/mmcom12/slides/mp3_and_aac_brandenburg.pdf">"MP3 and AAC Explained"</a> <span class="cs1-format">(PDF)</span>. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20170213191747/https://graphics.ethz.ch/teaching/mmcom12/slides/mp3_and_aac_brandenburg.pdf">Archived</a> <span class="cs1-format">(PDF)</span> from the original on 2017-02-13.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=MP3+and+AAC+Explained&rft.date=1999&rft.aulast=Brandenburg&rft.aufirst=Karlheinz&rft_id=http%3A%2F%2Fgraphics.ethz.ch%2Fteaching%2Fmmcom12%2Fslides%2Fmp3_and_aac_brandenburg.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALossy+compression" class="Z3988"></span></span> </li> <li id="cite_note-Darko_2017-11"><span class="mw-cite-backlink"><b><a href="#cite_ref-Darko_2017_11-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFDarko2017" class="citation web cs1">Darko, John H. (2017-03-29). <a rel="nofollow" class="external text" href="https://web.archive.org/web/20180114020200/http://www.digitalaudioreview.net/2017/03/the-inconvenient-truth-about-bluetooth-audio/">"The inconvenient truth about Bluetooth audio"</a>. <i>DAR__KO</i>. Archived from <a rel="nofollow" class="external text" href="http://www.digitalaudioreview.net/2017/03/the-inconvenient-truth-about-bluetooth-audio/">the original</a> on 2018-01-14<span class="reference-accessdate">. Retrieved <span class="nowrap">2018-01-13</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=DAR__KO&rft.atitle=The+inconvenient+truth+about+Bluetooth+audio&rft.date=2017-03-29&rft.aulast=Darko&rft.aufirst=John+H.&rft_id=http%3A%2F%2Fwww.digitalaudioreview.net%2F2017%2F03%2Fthe-inconvenient-truth-about-bluetooth-audio%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALossy+compression" class="Z3988"></span></span> </li> <li id="cite_note-AVHub_2015-12"><span class="mw-cite-backlink"><b><a href="#cite_ref-AVHub_2015_12-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFFord2015" class="citation web cs1">Ford, Jez (2015-08-24). <a rel="nofollow" class="external text" href="http://www.avhub.com.au/news/sound-image/what-is-sony-ldac-and-how-does-it-do-it-408285">"What is Sony LDAC, and how does it do it?"</a>. <i>AVHub</i><span class="reference-accessdate">. Retrieved <span class="nowrap">2018-01-13</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=AVHub&rft.atitle=What+is+Sony+LDAC%2C+and+how+does+it+do+it%3F&rft.date=2015-08-24&rft.aulast=Ford&rft.aufirst=Jez&rft_id=http%3A%2F%2Fwww.avhub.com.au%2Fnews%2Fsound-image%2Fwhat-is-sony-ldac-and-how-does-it-do-it-408285&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALossy+compression" class="Z3988"></span></span> </li> <li id="cite_note-AVHub_2016-13"><span class="mw-cite-backlink"><b><a href="#cite_ref-AVHub_2016_13-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFFord2016" class="citation web cs1">Ford, Jez (2016-11-22). <a rel="nofollow" class="external text" href="http://www.avhub.com.au/news/sound-image/aptx-hd---lossless-or-lossy-442124">"aptX HD - lossless or lossy?"</a>. <i>AVHub</i><span class="reference-accessdate">. Retrieved <span class="nowrap">2018-01-13</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=AVHub&rft.atitle=aptX+HD+-+lossless+or+lossy%3F&rft.date=2016-11-22&rft.aulast=Ford&rft.aufirst=Jez&rft_id=http%3A%2F%2Fwww.avhub.com.au%2Fnews%2Fsound-image%2Faptx-hd---lossless-or-lossy-442124&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALossy+compression" class="Z3988"></span></span> </li> <li id="cite_note-14"><span class="mw-cite-backlink"><b><a href="#cite_ref-14">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFI._H._WITTEN" class="citation web cs1">I. H. WITTEN; et al. <a rel="nofollow" class="external text" href="http://compression.ru/download/articles/text/witten_1994cj_lossy_text_compression.pdf">"Semantic and Generative Models for Lossy Text Compression"</a> <span class="cs1-format">(PDF)</span>. The Computer Journal<span class="reference-accessdate">. Retrieved <span class="nowrap">2007-10-13</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Semantic+and+Generative+Models+for+Lossy+Text+Compression&rft.pub=The+Computer+Journal&rft.au=I.+H.+WITTEN&rft_id=http%3A%2F%2Fcompression.ru%2Fdownload%2Farticles%2Ftext%2Fwitten_1994cj_lossy_text_compression.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALossy+compression" 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=Lossy_compression&action=edit&section=24" 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="http://www.bobulous.org.uk/misc/lossy_audio_2006.html">Lossy audio formats</a>, comparing the speed and compression strength of five lossy audio formats.</li> <li><a rel="nofollow" class="external text" href="http://dvd-hq.info/data_compression.php">Data compression basics</a>, including chapters on lossy compression of images, audio and video.</li> <li><a rel="nofollow" class="external text" href="https://web.archive.org/web/20051003204116/http://membled.com/work/apps/lossy_png/">Lossy PNG image compression</a> at the <a href="/wiki/Wayback_Machine" title="Wayback Machine">Wayback Machine</a> (archived 2005-10-03)</li> <li><a rel="nofollow" class="external text" href="http://www.websiteoptimization.com/speed/tweak/lossy/">Using lossy GIF/PNG compression for the web (article)</a></li> <li><a rel="nofollow" class="external text" href="http://www.wfu.edu/~matthews/misc/jpg_vs_gif/JpgCompTest/JpgForArchive.html">JPG for Archiving</a>, comparing the suitability of JPG and lossless compression for image archives</li> <li><a rel="nofollow" class="external text" href="http://www.mbreducer.com/">JPG Image Compression</a>, Jpg, Png compressor tool</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="Data_compression_methods" 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"><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:Compression_methods" title="Template:Compression methods"><abbr title="View this template">v</abbr></a></li><li class="nv-talk"><a href="/wiki/Template_talk:Compression_methods" title="Template talk:Compression methods"><abbr title="Discuss this template">t</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:Compression_methods" title="Special:EditPage/Template:Compression methods"><abbr title="Edit this template">e</abbr></a></li></ul></div><div id="Data_compression_methods" style="font-size:114%;margin:0 4em"><a href="/wiki/Data_compression" title="Data compression">Data compression</a> methods</div></th></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Lossless_compression" title="Lossless compression">Lossless</a></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:7.0em;font-weight:normal;"><a href="/wiki/Entropy_coding" title="Entropy coding">Entropy type</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/Adaptive_coding" title="Adaptive coding">Adaptive coding</a></li> <li><a href="/wiki/Arithmetic_coding" title="Arithmetic coding">Arithmetic</a></li> <li><a href="/wiki/Asymmetric_numeral_systems" title="Asymmetric numeral systems">Asymmetric numeral systems</a></li> <li><a href="/wiki/Golomb_coding" title="Golomb coding">Golomb</a></li> <li><a href="/wiki/Huffman_coding" title="Huffman coding">Huffman</a> <ul><li><a href="/wiki/Adaptive_Huffman_coding" title="Adaptive Huffman coding">Adaptive</a></li> <li><a href="/wiki/Canonical_Huffman_code" title="Canonical Huffman code">Canonical</a></li> <li><a href="/wiki/Modified_Huffman_coding" title="Modified Huffman coding">Modified</a></li></ul></li> <li><a href="/wiki/Range_coding" title="Range coding">Range</a></li> <li><a href="/wiki/Shannon_coding" title="Shannon coding">Shannon</a></li> <li><a href="/wiki/Shannon%E2%80%93Fano_coding" title="Shannon–Fano coding">Shannon–Fano</a></li> <li><a href="/wiki/Shannon%E2%80%93Fano%E2%80%93Elias_coding" title="Shannon–Fano–Elias coding">Shannon–Fano–Elias</a></li> <li><a href="/wiki/Tunstall_coding" title="Tunstall coding">Tunstall</a></li> <li><a href="/wiki/Unary_coding" title="Unary coding">Unary</a></li> <li><a href="/wiki/Universal_code_(data_compression)" title="Universal code (data compression)">Universal</a> <ul><li><a href="/wiki/Exponential-Golomb_coding" title="Exponential-Golomb coding">Exp-Golomb</a></li> <li><a href="/wiki/Fibonacci_coding" title="Fibonacci coding">Fibonacci</a></li> <li><a href="/wiki/Elias_gamma_coding" title="Elias gamma coding">Gamma</a></li> <li><a href="/wiki/Levenshtein_coding" title="Levenshtein coding">Levenshtein</a></li></ul></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:7.0em;font-weight:normal;"><a href="/wiki/Dictionary_coder" title="Dictionary coder">Dictionary type</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/Byte_pair_encoding" title="Byte pair encoding">Byte pair encoding</a></li> <li><a href="/wiki/LZ77_and_LZ78" title="LZ77 and LZ78">Lempel–Ziv</a> <ul><li><a href="/wiki/842_(compression_algorithm)" title="842 (compression algorithm)">842</a></li> <li><a href="/wiki/LZ4_(compression_algorithm)" title="LZ4 (compression algorithm)">LZ4</a></li> <li><a href="/wiki/LZJB" class="mw-redirect" title="LZJB">LZJB</a></li> <li><a href="/wiki/Lempel%E2%80%93Ziv%E2%80%93Oberhumer" title="Lempel–Ziv–Oberhumer">LZO</a></li> <li><a href="/wiki/LZRW" title="LZRW">LZRW</a></li> <li><a href="/wiki/Lempel%E2%80%93Ziv%E2%80%93Storer%E2%80%93Szymanski" title="Lempel–Ziv–Storer–Szymanski">LZSS</a></li> <li><a href="/wiki/Lempel%E2%80%93Ziv%E2%80%93Welch" title="Lempel–Ziv–Welch">LZW</a></li> <li><a href="/wiki/LZWL" title="LZWL">LZWL</a></li> <li><a href="/wiki/Snappy_(compression)" title="Snappy (compression)">Snappy</a></li></ul></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:7.0em;font-weight:normal;">Other types</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/Burrows%E2%80%93Wheeler_transform" title="Burrows–Wheeler transform">BWT</a></li> <li><a href="/wiki/Context_tree_weighting" title="Context tree weighting">CTW</a></li> <li><a href="/wiki/Context_mixing" title="Context mixing">CM</a></li> <li><a href="/wiki/Delta_encoding" title="Delta encoding">Delta</a> <ul><li><a href="/wiki/Incremental_encoding" title="Incremental encoding">Incremental</a></li></ul></li> <li><a href="/wiki/Dynamic_Markov_compression" title="Dynamic Markov compression">DMC</a></li> <li><a href="/wiki/Differential_pulse-code_modulation" title="Differential pulse-code modulation">DPCM</a></li> <li><a href="/wiki/Grammar-based_code" title="Grammar-based code">Grammar</a> <ul><li><a href="/wiki/Re-Pair" title="Re-Pair">Re-Pair</a></li> <li><a href="/wiki/Sequitur_algorithm" title="Sequitur algorithm">Sequitur</a></li></ul></li> <li><a href="/wiki/Discrete_cosine_transform" title="Discrete cosine transform">LDCT</a></li> <li><a href="/wiki/Move-to-front_transform" title="Move-to-front transform">MTF</a></li> <li><a href="/wiki/PAQ" title="PAQ">PAQ</a></li> <li><a href="/wiki/Prediction_by_partial_matching" title="Prediction by partial matching">PPM</a></li> <li><a href="/wiki/Run-length_encoding" title="Run-length encoding">RLE</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:7.0em;font-weight:normal;">Hybrid</th><td class="navbox-list-with-group navbox-list navbox-even" style="padding:0"><div style="padding:0 0.25em"> <ul><li>LZ77 + Huffman <ul><li><a href="/wiki/Deflate" title="Deflate">Deflate</a></li> <li><a href="/wiki/LZX" title="LZX">LZX</a></li> <li><a href="/wiki/Lempel%E2%80%93Ziv%E2%80%93Stac" title="Lempel–Ziv–Stac">LZS</a></li></ul></li> <li>LZ77 + ANS <ul><li><a href="/wiki/LZFSE" title="LZFSE">LZFSE</a></li></ul></li> <li>LZ77 + Huffman + ANS <ul><li><a href="/wiki/Zstd" title="Zstd">Zstandard</a></li></ul></li> <li>LZ77 + Huffman + context <ul><li><a href="/wiki/Brotli" title="Brotli">Brotli</a></li></ul></li> <li>LZSS + Huffman <ul><li><a href="/wiki/LHA_(file_format)" title="LHA (file format)">LHA/LZH</a></li></ul></li> <li>LZ77 + Range <ul><li><a href="/wiki/Lempel%E2%80%93Ziv%E2%80%93Markov_chain_algorithm" title="Lempel–Ziv–Markov chain algorithm">LZMA</a></li> <li>LZHAM</li></ul></li> <li>RLE + BWT + MTF + Huffman <ul><li><a href="/wiki/Bzip2" title="Bzip2">bzip2</a></li></ul></li></ul> </div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a class="mw-selflink selflink">Lossy</a></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:7.0em;font-weight:normal;"><a href="/wiki/Transform_coding" title="Transform coding">Transform type</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/Discrete_cosine_transform" title="Discrete cosine transform">Discrete cosine transform</a> <ul><li><a href="/wiki/Discrete_cosine_transform" title="Discrete cosine transform">DCT</a></li> <li><a href="/wiki/Modified_discrete_cosine_transform" title="Modified discrete cosine transform">MDCT</a></li></ul></li> <li><a href="/wiki/Discrete_sine_transform" title="Discrete sine transform">DST</a></li> <li><a href="/wiki/Fast_Fourier_transform" title="Fast Fourier transform">FFT</a></li> <li><a href="/wiki/Wavelet_transform" title="Wavelet transform">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> <li><a href="/wiki/Set_partitioning_in_hierarchical_trees" title="Set partitioning in hierarchical trees">SPIHT</a></li></ul></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:7.0em;font-weight:normal;">Predictive type</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/Differential_pulse-code_modulation" title="Differential pulse-code modulation">DPCM</a> <ul><li><a href="/wiki/Adaptive_differential_pulse-code_modulation" title="Adaptive differential pulse-code modulation">ADPCM</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/Log_area_ratio" title="Log area ratio">LAR</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>Motion <ul><li><a href="/wiki/Motion_compensation" title="Motion compensation">Compensation</a></li> <li><a href="/wiki/Motion_estimation" title="Motion estimation">Estimation</a></li> <li><a href="/wiki/Motion_vector" class="mw-redirect" title="Motion vector">Vector</a></li></ul></li> <li><a href="/wiki/Psychoacoustics" title="Psychoacoustics">Psychoacoustic</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#Audio" title="Data compression">Audio</a></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:7.0em;font-weight:normal;">Concepts</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/Bit_rate" title="Bit rate">Bit rate</a> <ul><li><a href="/wiki/Average_bitrate" title="Average bitrate">ABR</a></li> <li><a href="/wiki/Constant_bitrate" title="Constant bitrate">CBR</a></li> <li><a href="/wiki/Variable_bitrate" title="Variable bitrate">VBR</a></li></ul></li> <li><a href="/wiki/Companding" title="Companding">Companding</a></li> <li><a href="/wiki/Convolution" title="Convolution">Convolution</a></li> <li><a href="/wiki/Dynamic_range" title="Dynamic range">Dynamic range</a></li> <li><a href="/wiki/Latency_(audio)" title="Latency (audio)">Latency</a></li> <li><a href="/wiki/Nyquist%E2%80%93Shannon_sampling_theorem" title="Nyquist–Shannon sampling theorem">Nyquist–Shannon theorem</a></li> <li><a href="/wiki/Sampling_(signal_processing)" title="Sampling (signal processing)">Sampling</a></li> <li><a href="/wiki/Silence_compression" title="Silence compression">Silence compression</a></li> <li><a href="/wiki/Sound_quality" title="Sound quality">Sound quality</a></li> <li><a href="/wiki/Speech_coding" title="Speech coding">Speech coding</a></li> <li><a href="/wiki/Sub-band_coding" title="Sub-band coding">Sub-band coding</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:7.0em;font-weight:normal;"><a href="/wiki/Audio_codec" title="Audio codec">Codec</a> parts</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/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/Differential_pulse-code_modulation" title="Differential pulse-code modulation">DPCM</a> <ul><li><a href="/wiki/Adaptive_differential_pulse-code_modulation" title="Adaptive differential pulse-code modulation">ADPCM</a></li> <li><a href="/wiki/Delta_modulation" title="Delta modulation">DM</a></li></ul></li> <li><a href="/wiki/Fourier_transform" title="Fourier transform">FT</a> <ul><li><a href="/wiki/Fast_Fourier_transform" title="Fast Fourier transform">FFT</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/Log_area_ratio" title="Log area ratio">LAR</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/Modified_discrete_cosine_transform" title="Modified discrete cosine transform">MDCT</a></li> <li><a href="/wiki/Psychoacoustics" title="Psychoacoustics">Psychoacoustic model</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</a></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:7.0em;font-weight:normal;">Concepts</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/Chroma_subsampling" title="Chroma subsampling">Chroma subsampling</a></li> <li><a href="/wiki/Coding_tree_unit" title="Coding tree unit">Coding tree unit</a></li> <li><a href="/wiki/Color_space" title="Color space">Color space</a></li> <li><a href="/wiki/Compression_artifact" title="Compression artifact">Compression artifact</a></li> <li><a href="/wiki/Image_resolution" title="Image resolution">Image resolution</a></li> <li><a href="/wiki/Macroblock" title="Macroblock">Macroblock</a></li> <li><a href="/wiki/Pixel" title="Pixel">Pixel</a></li> <li><a href="/wiki/Peak_signal-to-noise_ratio" title="Peak signal-to-noise ratio">PSNR</a></li> <li><a href="/wiki/Quantization_(image_processing)" title="Quantization (image processing)">Quantization</a></li> <li><a href="/wiki/Standard_test_image" title="Standard test image">Standard test image</a></li> <li><a href="/wiki/Texture_compression" title="Texture compression">Texture compression</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:7.0em;font-weight:normal;">Methods</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/Chain_code" title="Chain code">Chain code</a></li> <li><a href="/wiki/Discrete_cosine_transform" title="Discrete cosine transform">DCT</a></li> <li><a href="/wiki/Deflate" title="Deflate">Deflate</a></li> <li><a href="/wiki/Fractal_compression" title="Fractal compression">Fractal</a></li> <li><a href="/wiki/Karhunen%E2%80%93Lo%C3%A8ve_theorem" class="mw-redirect" title="Karhunen–Loève theorem">KLT</a></li> <li><a href="/wiki/Pyramid_(image_processing)" title="Pyramid (image processing)">LP</a></li> <li><a href="/wiki/Run-length_encoding" title="Run-length encoding">RLE</a></li> <li><a href="/wiki/Wavelet_transform" title="Wavelet transform">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> <li><a href="/wiki/Embedded_zerotrees_of_wavelet_transforms" title="Embedded zerotrees of wavelet transforms">EZW</a></li> <li><a href="/wiki/Set_partitioning_in_hierarchical_trees" title="Set partitioning in hierarchical trees">SPIHT</a></li></ul></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</a></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:7.0em;font-weight:normal;">Concepts</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/Bit_rate" title="Bit rate">Bit rate</a> <ul><li><a href="/wiki/Average_bitrate" title="Average bitrate">ABR</a></li> <li><a href="/wiki/Constant_bitrate" title="Constant bitrate">CBR</a></li> <li><a href="/wiki/Variable_bitrate" title="Variable bitrate">VBR</a></li></ul></li> <li><a href="/wiki/Display_resolution" title="Display resolution">Display resolution</a></li> <li><a href="/wiki/Film_frame" title="Film frame">Frame</a></li> <li><a href="/wiki/Frame_rate" title="Frame rate">Frame rate</a></li> <li><a href="/wiki/Video_compression_picture_types" title="Video compression picture types">Frame types</a></li> <li><a href="/wiki/Interlaced_video" title="Interlaced video">Interlace</a></li> <li><a href="/wiki/Video#Characteristics_of_video_streams" title="Video">Video characteristics</a></li> <li><a href="/wiki/Video_quality" title="Video quality">Video quality</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:7.0em;font-weight:normal;"><a href="/wiki/Video_codec" title="Video codec">Codec</a> parts</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/Discrete_cosine_transform" title="Discrete cosine transform">DCT</a></li> <li><a href="/wiki/Differential_pulse-code_modulation" title="Differential pulse-code modulation">DPCM</a></li> <li><a href="/wiki/Deblocking_filter" title="Deblocking filter">Deblocking filter</a></li> <li><a href="/wiki/Lapped_transform" title="Lapped transform">Lapped transform</a></li> <li>Motion <ul><li><a href="/wiki/Motion_compensation" title="Motion compensation">Compensation</a></li> <li><a href="/wiki/Motion_estimation" title="Motion estimation">Estimation</a></li> <li><a href="/wiki/Motion_vector" class="mw-redirect" title="Motion vector">Vector</a></li></ul></li> <li><a href="/wiki/Wavelet_transform" title="Wavelet transform">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> </div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Information_theory" title="Information theory">Theory</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/Compressed_data_structure" title="Compressed data structure">Compressed data structures</a> <ul><li><a href="/wiki/Compressed_suffix_array" title="Compressed suffix array">Compressed suffix array</a></li> <li><a href="/wiki/FM-index" title="FM-index">FM-index</a></li></ul></li> <li><a href="/wiki/Entropy_(information_theory)" title="Entropy (information theory)">Entropy</a></li> <li><a href="/wiki/Information_theory" title="Information theory">Information theory</a> <ul><li><a href="/wiki/Timeline_of_information_theory" title="Timeline of information theory">Timeline</a></li></ul></li> <li><a href="/wiki/Kolmogorov_complexity" title="Kolmogorov complexity">Kolmogorov complexity</a></li> <li><a href="/wiki/Prefix_code" title="Prefix code">Prefix code</a></li> <li><a href="/wiki/Quantization_(signal_processing)" title="Quantization (signal processing)">Quantization</a></li> <li><a href="/wiki/Rate%E2%80%93distortion_theory" title="Rate–distortion theory">Rate–distortion</a></li> <li><a href="/wiki/Redundancy_(information_theory)" title="Redundancy (information theory)">Redundancy</a></li> <li><a href="/wiki/Data_compression_symmetry" title="Data compression symmetry">Symmetry</a></li> <li><a href="/wiki/Smallest_grammar_problem" title="Smallest grammar problem">Smallest grammar problem</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Community</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/Hutter_Prize" title="Hutter Prize">Hutter Prize</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">People</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/Mark_Adler" title="Mark Adler">Mark Adler</a></li></ul> </div></td></tr><tr><td class="navbox-abovebelow" colspan="2"><div> <ul><li><span class="noviewer" typeof="mw:File"><span title="Template"><img alt="" src="//upload.wikimedia.org/wikipedia/commons/thumb/8/83/Symbol_template_class_pink.svg/16px-Symbol_template_class_pink.svg.png" decoding="async" width="16" height="16" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/8/83/Symbol_template_class_pink.svg/23px-Symbol_template_class_pink.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/8/83/Symbol_template_class_pink.svg/31px-Symbol_template_class_pink.svg.png 2x" data-file-width="180" data-file-height="185" /></span></span> <a href="/wiki/Template:Compression_formats" title="Template:Compression formats">Compression formats</a></li> <li><span class="noviewer" typeof="mw:File"><span title="Template"><img alt="" src="//upload.wikimedia.org/wikipedia/commons/thumb/8/83/Symbol_template_class_pink.svg/16px-Symbol_template_class_pink.svg.png" decoding="async" width="16" height="16" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/8/83/Symbol_template_class_pink.svg/23px-Symbol_template_class_pink.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/8/83/Symbol_template_class_pink.svg/31px-Symbol_template_class_pink.svg.png 2x" data-file-width="180" data-file-height="185" /></span></span> <a href="/wiki/Template:Compression_software" title="Template:Compression software">Compression software</a> (<a href="/wiki/Codec" title="Codec">codecs</a>)</li></ul> </div></td></tr></tbody></table></div>    </div><noscript><img src="https://login.wikimedia.org/wiki/Special:CentralAutoLogin/start?type=1x1" 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=Lossy_compression&oldid=1254927363">https://en.wikipedia.org/w/index.php?title=Lossy_compression&oldid=1254927363</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:Data_compression" title="Category:Data compression">Data compression</a></li><li><a href="/wiki/Category:Lossy_compression_algorithms" title="Category:Lossy compression algorithms">Lossy compression algorithms</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: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><li><a href="/wiki/Category:All_articles_with_unsourced_statements" title="Category:All articles with unsourced statements">All articles with unsourced statements</a></li><li><a href="/wiki/Category:Articles_with_unsourced_statements_from_November_2019" title="Category:Articles with unsourced statements from November 2019">Articles with unsourced statements from November 2019</a></li><li><a href="/wiki/Category:Webarchive_template_wayback_links" title="Category:Webarchive template wayback links">Webarchive template wayback links</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 2 November 2024, at 10:20<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=Lossy_compression&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://wikimediafoundation.org/" class="cdx-button cdx-button--fake-button cdx-button--size-large cdx-button--fake-button--enabled"><img src="/static/images/footer/wikimedia-button.svg" width="84" height="29" alt="Wikimedia Foundation" loading="lazy"></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"><img src="/w/resources/assets/poweredby_mediawiki.svg" alt="Powered by MediaWiki" width="88" height="31" loading="lazy"></a></li> </ul> </footer> </div> </div> </div> <div class="vector-settings" id="p-dock-bottom"> <ul></ul> </div><script>(RLQ=window.RLQ||[]).push(function(){mw.config.set({"wgHostname":"mw-web.codfw.main-f69cdc8f6-rxt7p","wgBackendResponseTime":172,"wgPageParseReport":{"limitreport":{"cputime":"0.392","walltime":"0.516","ppvisitednodes":{"value":1588,"limit":1000000},"postexpandincludesize":{"value":79347,"limit":2097152},"templateargumentsize":{"value":1483,"limit":2097152},"expansiondepth":{"value":12,"limit":100},"expensivefunctioncount":{"value":11,"limit":500},"unstrip-depth":{"value":1,"limit":20},"unstrip-size":{"value":56169,"limit":5000000},"entityaccesscount":{"value":0,"limit":400},"timingprofile":["100.00% 392.155 1 -total"," 26.23% 102.844 6 Template:Navbox"," 25.64% 100.559 1 Template:Compression_Methods"," 22.06% 86.500 2 Template:Cite_journal"," 15.38% 60.316 1 Template:Short_description"," 9.29% 36.431 9 Template:Cite_web"," 8.93% 35.017 2 Template:Pagetype"," 8.53% 33.455 1 Template:Citation_needed"," 7.40% 29.017 1 Template:Fix"," 5.19% 20.346 1 Template:Main"]},"scribunto":{"limitreport-timeusage":{"value":"0.243","limit":"10.000"},"limitreport-memusage":{"value":5544890,"limit":52428800}},"cachereport":{"origin":"mw-web.codfw.main-f69cdc8f6-vbwr2","timestamp":"20241122142101","ttl":2592000,"transientcontent":false}}});});</script> <script type="application/ld+json">{"@context":"https:\/\/schema.org","@type":"Article","name":"Lossy compression","url":"https:\/\/en.wikipedia.org\/wiki\/Lossy_compression","sameAs":"http:\/\/www.wikidata.org\/entity\/Q55564","mainEntity":"http:\/\/www.wikidata.org\/entity\/Q55564","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":"2001-10-01T14:25:45Z","dateModified":"2024-11-02T10:20:11Z","image":"https:\/\/upload.wikimedia.org\/wikipedia\/commons\/a\/a4\/Comparison_of_JPEG_and_PNG.png","headline":"data compression approach that results in loss or change of some data"}</script> </body> </html>