{"id":2208,"date":"2025-07-19T13:16:48","date_gmt":"2025-07-19T11:16:48","guid":{"rendered":"https:\/\/localdab.org\/?page_id=2208"},"modified":"2025-07-20T09:45:37","modified_gmt":"2025-07-20T07:45:37","slug":"aac","status":"publish","type":"page","link":"https:\/\/localdab.org\/index.php\/glossary\/a-d\/aac\/","title":{"rendered":"AAC"},"content":{"rendered":"\n<p class=\"has-large-font-size wp-block-paragraph\">AAC<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\"><strong>A<\/strong>dvanced <strong>A<\/strong>udio <strong>C<\/strong>oding<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">A general audio coding standard designed as a successor to MP3 that generally offers better sound quality at the same bit rate.<\/p>\n\n\n\n<div style=\"height:30px\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n\n\n\n<p class=\"has-large-font-size wp-block-paragraph\">AAC-LC<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\"><strong>A<\/strong>dvanced <strong>A<\/strong>udio <strong>C<\/strong>oding &#8211; <strong>L<\/strong>ow <strong>C<\/strong>omplexity<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">It is an audio codec used for lossy compression of digital audio. AAC-LC is a specific profile within the AAC standard, known for its good sound quality at low bitrates and relatively low complexity, making it suitable for devices with limited computing power.<\/p>\n\n\n\n<div style=\"height:30px\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n\n\n\n<p class=\"has-large-font-size wp-block-paragraph\">HE-AAC<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\"><strong>H<\/strong>igh-<strong>E<\/strong>fficiency <strong>A<\/strong>dvanced <strong>A<\/strong>udio <strong>C<\/strong>oding<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">HE-AAC, also known as AAC-plus or AAC-SBR, is a lossy audio compression format that is an enhancement of the Advanced Audio Coding (AAC) standard. It utilizes <a href=\"https:\/\/localdab.org\/index.php\/glossary\/q-t\/sbr\/\" data-type=\"page\" data-id=\"2078\" target=\"_blank\" rel=\"noreferrer noopener\">Spectral Band Replication (SBR)<\/a> to achieve higher compression efficiency, particularly at lower bitrates, making it suitable for streaming and mobile applications.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">Key Features:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li class=\"has-medium-font-size\">Spectral Band Replication (SBR) : HE-AAC uses SBR to encode high-frequency information separately and reconstruct it at the decoder, effectively reducing the bitrate needed for high-quality audio<\/li>\n<\/ul>\n\n\n\n<ul class=\"wp-block-list\">\n<li class=\"has-medium-font-size\">Low Bitrate Performance : It is designed to deliver good audio quality even at lower bitrates (e.g., 32-64 kbps for stereo) compared to other codecs like AAC-LC<\/li>\n<\/ul>\n\n\n\n<ul class=\"wp-block-list\">\n<li class=\"has-medium-font-size\">Suitable for Streaming and Mobile : HE-AAC is widely used for streaming music services, internet radio, and digital broadcasting where bandwidth and storage are limited<\/li>\n<\/ul>\n\n\n\n<ul class=\"wp-block-list\">\n<li class=\"has-medium-font-size\">Standardized : HE-AAC is standardized as a profile of MPEG-4 Audio<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\"><\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">How it Works?<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li class=\"has-medium-font-size\"><strong>AAC Encoding:<\/strong> The core audio signal is encoded using the standard AAC-LC (Low Complexity) algorithm<\/li>\n<\/ul>\n\n\n\n<ul class=\"wp-block-list\">\n<li class=\"has-medium-font-size\"><strong>SBR Encoding:<\/strong> The high-frequency components of the audio are encoded using SBR, which effectively reduces the sampling rate and stores the missing high frequencies in side information<\/li>\n<\/ul>\n\n\n\n<ul class=\"wp-block-list\">\n<li class=\"has-medium-font-size\"><strong>Decoding:<\/strong> The HE-AAC decoder restores the high frequencies using the SBR data<\/li>\n<\/ul>\n\n\n\n<div style=\"height:30px\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n\n\n\n<p class=\"has-large-font-size wp-block-paragraph\">HE-AAC v2<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\"><strong>H<\/strong>igh-<strong>E<\/strong>fficiency <strong>A<\/strong>dvanced <strong>A<\/strong>udio <strong>C<\/strong>oding <strong>v2<\/strong><\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">HE-AAC v2 builds upon HE-AAC by adding <a href=\"https:\/\/localdab.org\/index.php\/glossary\/m-p\/ps\/\" data-type=\"page\" data-id=\"2081\" target=\"_blank\" rel=\"noreferrer noopener\">Parametric Stereo (PS)<\/a> for stereo signals, further improving compression efficiency, especially at very low bitrates.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">Key Features:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li class=\"has-medium-font-size\">AAC (see above)<\/li>\n<\/ul>\n\n\n\n<ul class=\"wp-block-list\">\n<li class=\"has-medium-font-size\">SBR (see above)<\/li>\n<\/ul>\n\n\n\n<ul class=\"wp-block-list\">\n<li class=\"has-medium-font-size\">PS (Parametric Stereo): A method of compressing stereo sound by generating additional information about the left and right channels, resulting in efficient stereo compression<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\"><a href=\"https:\/\/localdab.org\/index.php\/glossary\/\" data-type=\"page\" data-id=\"15\">Back<\/a><\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><\/p>\n","protected":false},"excerpt":{"rendered":"<p>AAC Advanced Audio Coding A general audio coding standard designed as a successor to MP3 that generally offers better sound quality at the same bit rate. AAC-LC Advanced Audio Coding &#8211; Low Complexity It is an audio codec used for lossy compression of digital audio. AAC-LC is a specific profile within the AAC standard, known [&hellip;]<\/p>\n","protected":false},"author":2,"featured_media":0,"parent":1257,"menu_order":10,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-2208","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/localdab.org\/index.php\/wp-json\/wp\/v2\/pages\/2208","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/localdab.org\/index.php\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/localdab.org\/index.php\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/localdab.org\/index.php\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/localdab.org\/index.php\/wp-json\/wp\/v2\/comments?post=2208"}],"version-history":[{"count":7,"href":"https:\/\/localdab.org\/index.php\/wp-json\/wp\/v2\/pages\/2208\/revisions"}],"predecessor-version":[{"id":2229,"href":"https:\/\/localdab.org\/index.php\/wp-json\/wp\/v2\/pages\/2208\/revisions\/2229"}],"up":[{"embeddable":true,"href":"https:\/\/localdab.org\/index.php\/wp-json\/wp\/v2\/pages\/1257"}],"wp:attachment":[{"href":"https:\/\/localdab.org\/index.php\/wp-json\/wp\/v2\/media?parent=2208"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}