{"id":3239,"date":"2021-10-29T14:14:21","date_gmt":"2021-10-29T17:14:21","guid":{"rendered":"https:\/\/www.ufsm.br\/pet\/sistemas-de-informacao\/?p=3239"},"modified":"2025-09-02T14:25:25","modified_gmt":"2025-09-02T17:25:25","slug":"codecs","status":"publish","type":"post","link":"https:\/\/www.ufsm.br\/pet\/sistemas-de-informacao\/2021\/10\/29\/codecs","title":{"rendered":"CODECS"},"content":{"rendered":"\n<p class=\"western\" lang=\"en-US\"><span style=\"font-family: Arial, serif\"><span style=\"font-size: medium\"><span lang=\"pt-BR\">Ea\u00ed pessoal, tudo tranquilo?<\/span><\/span><\/span><\/p>\n<p class=\"western\" lang=\"en-US\"><span style=\"font-family: Arial, serif\"><span style=\"font-size: medium\"><span lang=\"pt-BR\">Voc\u00ea j\u00e1 ouviu falar alguma vez por a\u00ed em Codec? Codec \u00e9 uma maneira de compress\u00e3o e descompress\u00e3o de arquivos, geralmente os de \u00e1udio e v\u00eddeo, como na internet n\u00e3o existe s\u00f3 uma maneira de compress\u00e3o e sim centenas, cada uma adotando uma t\u00e9cnica diferente. Hoje iremos abordar um contexto geral e como elas funcionam.<\/span><\/span><\/span><\/p>\n<p class=\"western\" lang=\"en-US\"><span style=\"font-family: Arial, serif\"><span style=\"font-size: medium\"><span lang=\"pt-BR\">Primeiro vamos come\u00e7ar entendo como funciona a nossa tela. A nossa tela \u00e9 formada por pixels, que nada mais do que uma matriz que armazena 3 valores <\/span><\/span><\/span><span style=\"color: #ff0000\"><span style=\"font-family: Arial, serif\"><span style=\"font-size: medium\"><span lang=\"pt-BR\">R = red<\/span><\/span><\/span><\/span><span style=\"font-family: Arial, serif\"><span style=\"font-size: medium\"><span lang=\"pt-BR\">, <\/span><\/span><\/span><span style=\"color: #00b050\"><span style=\"font-family: Arial, serif\"><span style=\"font-size: medium\"><span lang=\"pt-BR\">G = green<\/span><\/span><\/span><\/span><span style=\"font-family: Arial, serif\"><span style=\"font-size: medium\"><span lang=\"pt-BR\">, <\/span><\/span><\/span><span style=\"color: #0070c0\"><span style=\"font-family: Arial, serif\"><span style=\"font-size: medium\"><span lang=\"pt-BR\">B = blue,<\/span><\/span><\/span><\/span><span style=\"font-family: Arial, serif\"><span style=\"font-size: medium\"><span lang=\"pt-BR\"> 2<\/span><\/span><\/span><sup><span style=\"font-family: Arial, serif\"><span style=\"font-size: medium\"><span lang=\"pt-BR\">8 <\/span><\/span><\/span><\/sup><span style=\"font-family: Arial, serif\"><span style=\"font-size: medium\"><span lang=\"pt-BR\">ou 256 cores diferentes, quando os 3 valores s\u00e3o combinados em cada pixel temos 2<\/span><\/span><\/span><sup><span style=\"font-family: Arial, serif\"><span style=\"font-size: medium\"><span lang=\"pt-BR\">8&#215;3<\/span><\/span><\/span><\/sup><span style=\"font-family: Arial, serif\"><span style=\"font-size: medium\"><span lang=\"pt-BR\"> o que d\u00e1 em torno de 16 milh\u00f5es de cores diferentes.<\/span><\/span><\/span><\/p>\n<p class=\"western\"><img fetchpriority=\"high\" decoding=\"async\" class=\"aligncenter wp-image-3245 size-full\" src=\"https:\/\/www.ufsm.br\/app\/uploads\/sites\/791\/2021\/10\/WhatsApp-Image-2021-10-29-at-14.04.22.jpeg\" alt=\"\" width=\"240\" height=\"210\" \/><span style=\"font-family: Arial, serif\"><span style=\"font-size: medium\"><span lang=\"pt-BR\"><br \/>Agora que j\u00e1 sabemos como funciona a nossa tela vamos fazer um c\u00e1lculo de quanto pesa uma imagem em FULL HD sem compress\u00e3o, apenas com os pixels da tela. 1080 x 1920 x 24 = 49766400 bits, e fazendo as convers\u00f5es de armazenamento, dariam 6MB em apenas uma imagem.<\/span><\/span><\/span><\/p>\n<p class=\"western\" lang=\"en-US\"><span style=\"font-family: Arial, serif\"><span style=\"font-size: medium\"><span lang=\"pt-BR\">Agora e se for 1 segundo? Em um segundo s\u00e3o passadas 30 imagens, logo 6 x 30 = 180MB.<\/span><\/span><\/span><\/p>\n<p class=\"western\" lang=\"en-US\"><span style=\"font-family: Arial, serif\"><span style=\"font-size: medium\"><span lang=\"pt-BR\">E por fim em 1 minuto um v\u00eddeo pesaria 11 Gb.<\/span><\/span><\/span><\/p>\n<p class=\"western\" lang=\"en-US\"><span style=\"font-family: Arial, serif\"><span style=\"font-size: medium\"><span lang=\"pt-BR\">Para isso os codecs surgiram de uma necessidade de reduzir o tamanho dos arquivos de \u00e1udio e v\u00eddeo, pois os arquivos seriam enormes e levariam dias ou at\u00e9 semanas para transportar v\u00eddeos ou filmes.<\/span><\/span><\/span><\/p>\n<p class=\"western\" lang=\"en-US\"><img decoding=\"async\" class=\"aligncenter wp-image-3241 size-full\" src=\"https:\/\/www.ufsm.br\/app\/uploads\/sites\/791\/2021\/10\/WhatsApp-Image-2021-10-29-at-14.04.23.jpeg\" alt=\"\" width=\"800\" height=\"298\" srcset=\"https:\/\/www.ufsm.br\/app\/uploads\/sites\/791\/2021\/10\/WhatsApp-Image-2021-10-29-at-14.04.23.jpeg 800w, https:\/\/www.ufsm.br\/app\/uploads\/sites\/791\/2021\/10\/WhatsApp-Image-2021-10-29-at-14.04.23-300x112.jpeg 300w, https:\/\/www.ufsm.br\/app\/uploads\/sites\/791\/2021\/10\/WhatsApp-Image-2021-10-29-at-14.04.23-768x286.jpeg 768w\" sizes=\"(max-width: 800px) 100vw, 800px\" \/><\/p>\n<p class=\"western\" lang=\"en-US\"><span style=\"font-family: Arial, serif\"><span style=\"font-size: medium\"><span lang=\"pt-BR\">Como dito, o processo de compress\u00e3o dos arquivos possui v\u00e1rias etapas com elas:<\/span><\/span><\/span><\/p>\n<ul>\n<li>\n<p lang=\"en-US\"><span style=\"font-family: Arial, serif\"><span style=\"font-size: medium\"><span lang=\"pt-BR\"><b>Codecs de Captura: <\/b><\/span><\/span><\/span><span style=\"font-family: Arial, serif\"><span style=\"font-size: medium\"><span lang=\"pt-BR\">Este processo come\u00e7a j\u00e1 nas c\u00e2meras fotogr\u00e1ficas que entre elas possuem diferentes modos de compress\u00e3o.<\/span><\/span><\/span><\/p>\n<\/li>\n<\/ul>\n<ol>\n<li>\n<p lang=\"en-US\"><span style=\"font-family: Arial, serif\"><span style=\"font-size: medium\"><span lang=\"pt-BR\">O m\u00e9todo <\/span><\/span><\/span><span style=\"font-family: Arial, serif\"><span style=\"font-size: medium\"><span lang=\"pt-BR\"><b>4:4:4<\/b><\/span><\/span><\/span><span style=\"font-family: Arial, serif\"><span style=\"font-size: medium\"><span lang=\"pt-BR\"> \u00e9 melhor existente, pois dentro de 4 pixels, todos eles ter\u00e3o o seu valor original, nenhuma informa\u00e7\u00e3o da cor \u00e9 perdida, ent\u00e3o a qualidade \u00e9 melhor ao custo de mais informa\u00e7\u00e3o.<\/span><\/span><\/span><\/p>\n<\/li>\n<\/ol>\n<p lang=\"en-US\"><img decoding=\"async\" class=\"aligncenter wp-image-3244 size-full\" src=\"https:\/\/www.ufsm.br\/app\/uploads\/sites\/791\/2021\/10\/WhatsApp-Image-2021-10-29-at-14.04.22-1.jpeg\" alt=\"\" width=\"1280\" height=\"894\" srcset=\"https:\/\/www.ufsm.br\/app\/uploads\/sites\/791\/2021\/10\/WhatsApp-Image-2021-10-29-at-14.04.22-1.jpeg 1280w, https:\/\/www.ufsm.br\/app\/uploads\/sites\/791\/2021\/10\/WhatsApp-Image-2021-10-29-at-14.04.22-1-300x210.jpeg 300w, https:\/\/www.ufsm.br\/app\/uploads\/sites\/791\/2021\/10\/WhatsApp-Image-2021-10-29-at-14.04.22-1-1024x715.jpeg 1024w, https:\/\/www.ufsm.br\/app\/uploads\/sites\/791\/2021\/10\/WhatsApp-Image-2021-10-29-at-14.04.22-1-768x536.jpeg 768w\" sizes=\"(max-width: 1280px) 100vw, 1280px\" \/><\/p>\n<p>\u00a0<\/p>\n<ol start=\"2\">\n<li>\n<p lang=\"en-US\"><span style=\"font-family: Arial, serif\"><span style=\"font-size: medium\"><span lang=\"pt-BR\">Mas alguns codecs reduzem isso como por exemplo o m\u00e9todo <\/span><\/span><\/span><span style=\"font-family: Arial, serif\"><span style=\"font-size: medium\"><span lang=\"pt-BR\"><b>4:2:2, <\/b><\/span><\/span><\/span><span style=\"font-family: Arial, serif\"><span style=\"font-size: medium\"><span lang=\"pt-BR\">que consiste em num raio de 4 pixels, 2 ter\u00e3o o seu valor trocado pelo pr\u00f3ximo, o que ocasiona em uma grande redu\u00e7\u00e3o de espa\u00e7o, ao custo de perder qualidade.<\/span><\/span><\/span><\/p>\n<\/li>\n<\/ol>\n<p class=\"western\" lang=\"en-US\"><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter wp-image-3243 size-full\" src=\"https:\/\/www.ufsm.br\/app\/uploads\/sites\/791\/2021\/10\/WhatsApp-Image-2021-10-29-at-14.04.22-2.jpeg\" alt=\"\" width=\"1280\" height=\"862\" srcset=\"https:\/\/www.ufsm.br\/app\/uploads\/sites\/791\/2021\/10\/WhatsApp-Image-2021-10-29-at-14.04.22-2.jpeg 1280w, https:\/\/www.ufsm.br\/app\/uploads\/sites\/791\/2021\/10\/WhatsApp-Image-2021-10-29-at-14.04.22-2-300x202.jpeg 300w, https:\/\/www.ufsm.br\/app\/uploads\/sites\/791\/2021\/10\/WhatsApp-Image-2021-10-29-at-14.04.22-2-1024x690.jpeg 1024w, https:\/\/www.ufsm.br\/app\/uploads\/sites\/791\/2021\/10\/WhatsApp-Image-2021-10-29-at-14.04.22-2-768x517.jpeg 768w, https:\/\/www.ufsm.br\/app\/uploads\/sites\/791\/2021\/10\/WhatsApp-Image-2021-10-29-at-14.04.22-2-272x182.jpeg 272w\" sizes=\"(max-width: 1280px) 100vw, 1280px\" \/><\/p>\n<ol start=\"3\">\n<li>\n<p lang=\"en-US\" align=\"justify\"><span style=\"font-family: Arial, serif\"><span style=\"font-size: medium\"><span lang=\"pt-BR\">Por fim, existe o m\u00e9todo que mais reduz espa\u00e7o e perde informa\u00e7\u00e3o o <\/span><\/span><\/span><span style=\"font-family: Arial, serif\"><span style=\"font-size: medium\"><span lang=\"pt-BR\"><b>4:2:0, <\/b><\/span><\/span><\/span><span style=\"font-family: Arial, serif\"><span style=\"font-size: medium\"><span lang=\"pt-BR\">que \u00e9 um dos mais utilizados por celulares e c\u00e2meras, o qual dos 4 pixels, apenas 1 ter\u00e1 o seu valor original de cor.<\/span><\/span><\/span><\/p>\n<\/li>\n<\/ol>\n<p class=\"western\" lang=\"en-US\"><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter wp-image-3242 size-full\" src=\"https:\/\/www.ufsm.br\/app\/uploads\/sites\/791\/2021\/10\/WhatsApp-Image-2021-10-29-at-14.04.22-3.jpeg\" alt=\"\" width=\"1280\" height=\"872\" srcset=\"https:\/\/www.ufsm.br\/app\/uploads\/sites\/791\/2021\/10\/WhatsApp-Image-2021-10-29-at-14.04.22-3.jpeg 1280w, https:\/\/www.ufsm.br\/app\/uploads\/sites\/791\/2021\/10\/WhatsApp-Image-2021-10-29-at-14.04.22-3-300x204.jpeg 300w, https:\/\/www.ufsm.br\/app\/uploads\/sites\/791\/2021\/10\/WhatsApp-Image-2021-10-29-at-14.04.22-3-1024x698.jpeg 1024w, https:\/\/www.ufsm.br\/app\/uploads\/sites\/791\/2021\/10\/WhatsApp-Image-2021-10-29-at-14.04.22-3-768x523.jpeg 768w\" sizes=\"(max-width: 1280px) 100vw, 1280px\" \/><\/p>\n<ul>\n<li>\n<p lang=\"en-US\"><span style=\"font-family: Arial, serif\"><span style=\"font-size: medium\"><span lang=\"pt-BR\"><b>Codecs de edi\u00e7\u00e3o<\/b><\/span><\/span><\/span><span style=\"font-family: Arial, serif\"><span style=\"font-size: medium\"><span lang=\"pt-BR\">: Agora que j\u00e1 passamos pelas partes de captura, vamos para a parte de edi\u00e7\u00e3o, onde os nossos computadores agem ou alguns outros aparelhos fotogr\u00e1ficos.<\/span><\/span><\/span><\/p>\n<\/li>\n<\/ul>\n<p lang=\"en-US\"><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter wp-image-3246 size-full\" src=\"https:\/\/www.ufsm.br\/app\/uploads\/sites\/791\/2021\/10\/WhatsApp-Image-2021-10-29-at-14.04.21.jpeg\" alt=\"\" width=\"500\" height=\"500\" srcset=\"https:\/\/www.ufsm.br\/app\/uploads\/sites\/791\/2021\/10\/WhatsApp-Image-2021-10-29-at-14.04.21.jpeg 500w, https:\/\/www.ufsm.br\/app\/uploads\/sites\/791\/2021\/10\/WhatsApp-Image-2021-10-29-at-14.04.21-300x300.jpeg 300w, https:\/\/www.ufsm.br\/app\/uploads\/sites\/791\/2021\/10\/WhatsApp-Image-2021-10-29-at-14.04.21-150x150.jpeg 150w\" sizes=\"(max-width: 500px) 100vw, 500px\" \/><\/p>\n<p class=\"western\" lang=\"en-US\"><span style=\"font-family: Arial, serif\"><span style=\"font-size: medium\"><span lang=\"pt-BR\"><b>Compress\u00e3o com perdas: <\/b><\/span><\/span><\/span><span style=\"font-family: Arial, serif\"><span style=\"font-size: medium\"><span lang=\"pt-BR\">O m\u00e9todo de compress\u00e3o com perdas reduz o formato do arquivo a ponto de estar num estado m\u00ednimo em que o ouvido e o olho humano n\u00e3o percebam, pois, esses tipos de codificadores removem apenas os ru\u00eddos que s\u00e3o impercept\u00edveis.<\/span><\/span><\/span><\/p>\n<p class=\"western\" lang=\"en-US\"><span style=\"font-family: Arial, serif\"><span style=\"font-size: medium\"><span lang=\"pt-BR\"><b>Compress\u00e3o sem perdas:<\/b><\/span><\/span><\/span><span style=\"font-family: Arial, serif\"><span style=\"font-size: medium\"><span lang=\"pt-BR\"> Esse m\u00e9todo como o pr\u00f3prio nome diz n\u00e3o h\u00e1 perdas significativas, mas n\u00e3o quer dizer que n\u00e3o comprimem nada, pois reduzem poucas partes do arquivo original.<\/span><\/span><\/span><\/p>\n<p class=\"western\" lang=\"en-US\"><span style=\"font-family: Arial, serif\"><span style=\"font-size: medium\"><span lang=\"pt-BR\"><b>Conclus\u00e3o: <\/b><\/span><\/span><\/span><span style=\"font-family: Arial, serif\"><span style=\"font-size: medium\"><span lang=\"pt-BR\">Existem diversos processos at\u00e9 os arquivos de \u00e1udio e v\u00eddeo chegarem ao nosso aparelho. Por isso se voc\u00ea curte estudar edi\u00e7\u00e3o ou grava\u00e7\u00e3o, \u00e9 importante ficar ligado nesses processos para o melhor entendimento do seu sistema.<\/span><\/span><\/span><\/p>\n<p lang=\"en-US\">\u00a0<\/p>\n<p style=\"text-align: right\">&#8211; Lu\u00eds Corr\u00eaa<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Ea\u00ed pessoal, tudo tranquilo? Voc\u00ea j\u00e1 ouviu falar alguma vez por a\u00ed em Codec? Codec \u00e9 uma maneira de compress\u00e3o e descompress\u00e3o de arquivos, geralmente os de \u00e1udio e v\u00eddeo, como na internet n\u00e3o existe s\u00f3 uma maneira de compress\u00e3o e sim centenas, cada uma adotando uma t\u00e9cnica diferente. Hoje iremos abordar um contexto geral [&hellip;]<\/p>\n","protected":false},"author":2948,"featured_media":3240,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[124,112],"tags":[184,149],"class_list":["post-3239","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-destaques","category-redacao","tag-ferramentas","tag-redacao"],"acf":[],"_links":{"self":[{"href":"https:\/\/www.ufsm.br\/pet\/sistemas-de-informacao\/wp-json\/wp\/v2\/posts\/3239","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.ufsm.br\/pet\/sistemas-de-informacao\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.ufsm.br\/pet\/sistemas-de-informacao\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.ufsm.br\/pet\/sistemas-de-informacao\/wp-json\/wp\/v2\/users\/2948"}],"replies":[{"embeddable":true,"href":"https:\/\/www.ufsm.br\/pet\/sistemas-de-informacao\/wp-json\/wp\/v2\/comments?post=3239"}],"version-history":[{"count":0,"href":"https:\/\/www.ufsm.br\/pet\/sistemas-de-informacao\/wp-json\/wp\/v2\/posts\/3239\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.ufsm.br\/pet\/sistemas-de-informacao\/wp-json\/wp\/v2\/media\/3240"}],"wp:attachment":[{"href":"https:\/\/www.ufsm.br\/pet\/sistemas-de-informacao\/wp-json\/wp\/v2\/media?parent=3239"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.ufsm.br\/pet\/sistemas-de-informacao\/wp-json\/wp\/v2\/categories?post=3239"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.ufsm.br\/pet\/sistemas-de-informacao\/wp-json\/wp\/v2\/tags?post=3239"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}