{"id":793,"date":"2026-01-25T09:51:17","date_gmt":"2026-01-25T01:51:17","guid":{"rendered":"https:\/\/ixriver.com\/?p=793"},"modified":"2026-01-25T09:51:17","modified_gmt":"2026-01-25T01:51:17","slug":"arq%e4%b8%8efec%e6%b7%b7%e5%90%88%e6%96%b9%e6%a1%88","status":"publish","type":"post","link":"https:\/\/finance.ixriver.com\/?p=793","title":{"rendered":"ARQ\u4e0eFEC\u6df7\u5408\u65b9\u6848"},"content":{"rendered":"<p>\u5728\u5e95\u5c42 UDP \u4f20\u8f93\u534f\u8bae\u4e2d\uff0c\u5355\u7eaf\u4f9d\u9760 FEC\uff08\u524d\u5411\u7ea0\u9519\uff09\u4f1a\u6d6a\u8d39\u5e26\u5bbd\uff0c\u5355\u7eaf\u4f9d\u9760 ARQ\uff08\u4e22\u5305\u91cd\u4f20\uff09\u4f1a\u5e26\u6765\u5de8\u5927\u7684\u5ef6\u8fdf\u3002<strong>ARQ+FEC \u6df7\u5408\u65b9\u6848\uff08Hybrid ARQ\uff09<\/strong> \u662f\u76ee\u524d\u5b9e\u65f6\u97f3\u89c6\u9891\u901a\u4fe1\uff08\u5982 WebRTC\u3001Zoom\uff09\u7684\u4e3b\u6d41\u65b9\u6848\u3002<\/p>\n<p>\u4ee5\u4e0b\u662f\u4e00\u4e2a\u5b8c\u6574\u7684\u5e95\u5c42\u5b9e\u73b0\u903b\u8f91\u6846\u67b6\uff1a<\/p>\n<hr \/>\n<div id=\"ez-toc-container\" class=\"ez-toc-v2_0_65 counter-hierarchy ez-toc-counter ez-toc-grey ez-toc-container-direction\">\n<div class=\"ez-toc-title-container\">\n<p class=\"ez-toc-title \" >\u76ee\u5f55<\/p>\n<span class=\"ez-toc-title-toggle\"><a href=\"#\" class=\"ez-toc-pull-right ez-toc-btn ez-toc-btn-xs ez-toc-btn-default ez-toc-toggle\" aria-label=\"Toggle Table of Content\"><span class=\"ez-toc-js-icon-con\"><span class=\"\"><span class=\"eztoc-hide\" style=\"display:none;\">Toggle<\/span><span class=\"ez-toc-icon-toggle-span\"><svg style=\"fill: #999;color:#999\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" class=\"list-377408\" width=\"20px\" height=\"20px\" viewBox=\"0 0 24 24\" fill=\"none\"><path d=\"M6 6H4v2h2V6zm14 0H8v2h12V6zM4 11h2v2H4v-2zm16 0H8v2h12v-2zM4 16h2v2H4v-2zm16 0H8v2h12v-2z\" fill=\"currentColor\"><\/path><\/svg><svg style=\"fill: #999;color:#999\" class=\"arrow-unsorted-368013\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"10px\" height=\"10px\" viewBox=\"0 0 24 24\" version=\"1.2\" baseProfile=\"tiny\"><path d=\"M18.2 9.3l-6.2-6.3-6.2 6.3c-.2.2-.3.4-.3.7s.1.5.3.7c.2.2.4.3.7.3h11c.3 0 .5-.1.7-.3.2-.2.3-.5.3-.7s-.1-.5-.3-.7zM5.8 14.7l6.2 6.3 6.2-6.3c.2-.2.3-.5.3-.7s-.1-.5-.3-.7c-.2-.2-.4-.3-.7-.3h-11c-.3 0-.5.1-.7.3-.2.2-.3.5-.3.7s.1.5.3.7z\"\/><\/svg><\/span><\/span><\/span><\/a><\/span><\/div>\n<nav><ul class='ez-toc-list ez-toc-list-level-1 ' ><ul class='ez-toc-list-level-3' ><li class='ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-1\" href=\"https:\/\/finance.ixriver.com\/?p=793\/#1_%E6%95%B4%E4%BD%93%E6%9E%B6%E6%9E%84%E8%AE%BE%E8%AE%A1\" title=\"1. \u6574\u4f53\u67b6\u6784\u8bbe\u8ba1\">1. \u6574\u4f53\u67b6\u6784\u8bbe\u8ba1<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-2\" href=\"https:\/\/finance.ixriver.com\/?p=793\/#2_%E5%8F%91%E9%80%81%E7%AB%AF_Sender_%E5%AE%9E%E7%8E%B0%E6%B5%81%E7%A8%8B\" title=\"2. \u53d1\u9001\u7aef (Sender) \u5b9e\u73b0\u6d41\u7a0b\">2. \u53d1\u9001\u7aef (Sender) \u5b9e\u73b0\u6d41\u7a0b<\/a><ul class='ez-toc-list-level-4' ><li class='ez-toc-heading-level-4'><a class=\"ez-toc-link ez-toc-heading-3\" href=\"https:\/\/finance.ixriver.com\/?p=793\/#A_%E5%B0%81%E5%8C%85%E4%B8%8E%E7%BC%93%E5%AD%98\" title=\"A. \u5c01\u5305\u4e0e\u7f13\u5b58\">A. \u5c01\u5305\u4e0e\u7f13\u5b58<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-4'><a class=\"ez-toc-link ez-toc-heading-4\" href=\"https:\/\/finance.ixriver.com\/?p=793\/#B_FEC_%E7%BC%96%E7%A0%81%E7%AD%96%E7%95%A5\" title=\"B. FEC \u7f16\u7801\u7b56\u7565\">B. FEC \u7f16\u7801\u7b56\u7565<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-4'><a class=\"ez-toc-link ez-toc-heading-5\" href=\"https:\/\/finance.ixriver.com\/?p=793\/#C_%E5%93%8D%E5%BA%94_ARQ_%E8%AF%B7%E6%B1%82\" title=\"C. \u54cd\u5e94 ARQ \u8bf7\u6c42\">C. \u54cd\u5e94 ARQ \u8bf7\u6c42<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-6\" href=\"https:\/\/finance.ixriver.com\/?p=793\/#3_%E6%8E%A5%E6%94%B6%E7%AB%AF_Receiver_%E5%AE%9E%E7%8E%B0%E6%B5%81%E7%A8%8B\" title=\"3. \u63a5\u6536\u7aef (Receiver) \u5b9e\u73b0\u6d41\u7a0b\">3. \u63a5\u6536\u7aef (Receiver) \u5b9e\u73b0\u6d41\u7a0b<\/a><ul class='ez-toc-list-level-4' ><li class='ez-toc-heading-level-4'><a class=\"ez-toc-link ez-toc-heading-7\" href=\"https:\/\/finance.ixriver.com\/?p=793\/#A_%E5%A4%84%E7%90%86%E9%80%BB%E8%BE%91%E6%B5%81%E6%B0%B4%E7%BA%BF\" title=\"A. \u5904\u7406\u903b\u8f91\u6d41\u6c34\u7ebf\">A. \u5904\u7406\u903b\u8f91\u6d41\u6c34\u7ebf<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-8\" href=\"https:\/\/finance.ixriver.com\/?p=793\/#4_%E5%85%B3%E9%94%AE%E7%AE%97%E6%B3%95%E4%B8%8E%E5%8D%8F%E8%AE%AE%E7%BB%86%E8%8A%82\" title=\"4. \u5173\u952e\u7b97\u6cd5\u4e0e\u534f\u8bae\u7ec6\u8282\">4. \u5173\u952e\u7b97\u6cd5\u4e0e\u534f\u8bae\u7ec6\u8282<\/a><ul class='ez-toc-list-level-4' ><li class='ez-toc-heading-level-4'><a class=\"ez-toc-link ez-toc-heading-9\" href=\"https:\/\/finance.ixriver.com\/?p=793\/#%E6%95%B0%E6%8D%AE%E5%8C%85%E7%BB%93%E6%9E%84%E5%AE%9A%E4%B9%89_C\" title=\"\u6570\u636e\u5305\u7ed3\u6784\u5b9a\u4e49 (C++)\">\u6570\u636e\u5305\u7ed3\u6784\u5b9a\u4e49 (C++)<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-4'><a class=\"ez-toc-link ez-toc-heading-10\" href=\"https:\/\/finance.ixriver.com\/?p=793\/#ARQ_%E7%9A%84%E2%80%9C%E9%99%90%E5%88%B6%E6%80%A7%E7%AD%96%E7%95%A5%E2%80%9D\" title=\"ARQ \u7684\u201c\u9650\u5236\u6027\u7b56\u7565\u201d\">ARQ \u7684\u201c\u9650\u5236\u6027\u7b56\u7565\u201d<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-11\" href=\"https:\/\/finance.ixriver.com\/?p=793\/#5_ARQ_%E4%B8%8E_FEC_%E7%9A%84%E5%8D%8F%E5%90%8C%E8%A7%A6%E5%8F%91%E7%AE%97%E6%B3%95\" title=\"5. ARQ \u4e0e FEC \u7684\u534f\u540c\u89e6\u53d1\u7b97\u6cd5\">5. ARQ \u4e0e FEC \u7684\u534f\u540c\u89e6\u53d1\u7b97\u6cd5<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-12\" href=\"https:\/\/finance.ixriver.com\/?p=793\/#6_%E5%AE%9E%E7%8E%B0%E5%BB%BA%E8%AE%AE\" title=\"6. \u5b9e\u73b0\u5efa\u8bae\">6. \u5b9e\u73b0\u5efa\u8bae<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-13\" href=\"https:\/\/finance.ixriver.com\/?p=793\/#WebRTC_%E7%9A%84_ARQ_%E5%92%8C_FEC_%E5%AE%9E%E7%8E%B0%E6%9C%BA%E5%88%B6\" title=\"WebRTC \u7684 ARQ \u548c FEC \u5b9e\u73b0\u673a\u5236\">WebRTC \u7684 ARQ \u548c FEC \u5b9e\u73b0\u673a\u5236<\/a><ul class='ez-toc-list-level-3' ><li class='ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-14\" href=\"https:\/\/finance.ixriver.com\/?p=793\/#WebRTC_ARQ_%E5%AE%9E%E7%8E%B0\" title=\"WebRTC ARQ \u5b9e\u73b0\">WebRTC ARQ \u5b9e\u73b0<\/a><ul class='ez-toc-list-level-4' ><li class='ez-toc-heading-level-4'><a class=\"ez-toc-link ez-toc-heading-15\" href=\"https:\/\/finance.ixriver.com\/?p=793\/#RTP_NACK%EF%BC%88Negative_Acknowledgment%EF%BC%89\" title=\"RTP NACK\uff08Negative Acknowledgment\uff09\">RTP NACK\uff08Negative Acknowledgment\uff09<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-4'><a class=\"ez-toc-link ez-toc-heading-16\" href=\"https:\/\/finance.ixriver.com\/?p=793\/#RTX%EF%BC%88RTP_Retransmission%EF%BC%89\" title=\"RTX\uff08RTP Retransmission\uff09\">RTX\uff08RTP Retransmission\uff09<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-4'><a class=\"ez-toc-link ez-toc-heading-17\" href=\"https:\/\/finance.ixriver.com\/?p=793\/#NACK_%E8%A7%A6%E5%8F%91%E7%AD%96%E7%95%A5\" title=\"NACK \u89e6\u53d1\u7b56\u7565\">NACK \u89e6\u53d1\u7b56\u7565<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-18\" href=\"https:\/\/finance.ixriver.com\/?p=793\/#WebRTC_FEC_%E5%AE%9E%E7%8E%B0\" title=\"WebRTC FEC \u5b9e\u73b0\">WebRTC FEC \u5b9e\u73b0<\/a><ul class='ez-toc-list-level-4' ><li class='ez-toc-heading-level-4'><a class=\"ez-toc-link ez-toc-heading-19\" href=\"https:\/\/finance.ixriver.com\/?p=793\/#ULPFEC%EF%BC%88Uneven_Level_Protection_FEC%EF%BC%89\" title=\"ULPFEC\uff08Uneven Level Protection FEC\uff09\">ULPFEC\uff08Uneven Level Protection FEC\uff09<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-4'><a class=\"ez-toc-link ez-toc-heading-20\" href=\"https:\/\/finance.ixriver.com\/?p=793\/#FlexFEC\" title=\"FlexFEC\">FlexFEC<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-21\" href=\"https:\/\/finance.ixriver.com\/?p=793\/#WebRTC_%E5%8D%8F%E5%90%8C%E6%9C%BA%E5%88%B6\" title=\"WebRTC \u534f\u540c\u673a\u5236\">WebRTC \u534f\u540c\u673a\u5236<\/a><ul class='ez-toc-list-level-4' ><li class='ez-toc-heading-level-4'><a class=\"ez-toc-link ez-toc-heading-22\" href=\"https:\/\/finance.ixriver.com\/?p=793\/#%E8%87%AA%E9%80%82%E5%BA%94%E7%AD%96%E7%95%A5\" title=\"\u81ea\u9002\u5e94\u7b56\u7565\">\u81ea\u9002\u5e94\u7b56\u7565<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-4'><a class=\"ez-toc-link ez-toc-heading-23\" href=\"https:\/\/finance.ixriver.com\/?p=793\/#RTT_%E8%87%AA%E9%80%82%E5%BA%94\" title=\"RTT \u81ea\u9002\u5e94\">RTT \u81ea\u9002\u5e94<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-4'><a class=\"ez-toc-link ez-toc-heading-24\" href=\"https:\/\/finance.ixriver.com\/?p=793\/#%E5%B8%A6%E5%AE%BD%E8%87%AA%E9%80%82%E5%BA%94\" title=\"\u5e26\u5bbd\u81ea\u9002\u5e94\">\u5e26\u5bbd\u81ea\u9002\u5e94<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-25\" href=\"https:\/\/finance.ixriver.com\/?p=793\/#WebRTC_%E5%85%B3%E9%94%AE%E5%AE%9E%E7%8E%B0%E7%BB%86%E8%8A%82\" title=\"WebRTC \u5173\u952e\u5b9e\u73b0\u7ec6\u8282\">WebRTC \u5173\u952e\u5b9e\u73b0\u7ec6\u8282<\/a><ul class='ez-toc-list-level-4' ><li class='ez-toc-heading-level-4'><a class=\"ez-toc-link ez-toc-heading-26\" href=\"https:\/\/finance.ixriver.com\/?p=793\/#%E5%8F%91%E9%80%81%E7%AB%AF%E5%AE%9E%E7%8E%B0\" title=\"\u53d1\u9001\u7aef\u5b9e\u73b0\">\u53d1\u9001\u7aef\u5b9e\u73b0<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-4'><a class=\"ez-toc-link ez-toc-heading-27\" href=\"https:\/\/finance.ixriver.com\/?p=793\/#%E6%8E%A5%E6%94%B6%E7%AB%AF%E5%AE%9E%E7%8E%B0\" title=\"\u63a5\u6536\u7aef\u5b9e\u73b0\">\u63a5\u6536\u7aef\u5b9e\u73b0<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-4'><a class=\"ez-toc-link ez-toc-heading-28\" href=\"https:\/\/finance.ixriver.com\/?p=793\/#%E7%BB%9F%E8%AE%A1%E5%92%8C%E5%8F%8D%E9%A6%88\" title=\"\u7edf\u8ba1\u548c\u53cd\u9988\">\u7edf\u8ba1\u548c\u53cd\u9988<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-29\" href=\"https:\/\/finance.ixriver.com\/?p=793\/#WebRTC_%E9%85%8D%E7%BD%AE%E5%BB%BA%E8%AE%AE\" title=\"WebRTC \u914d\u7f6e\u5efa\u8bae\">WebRTC \u914d\u7f6e\u5efa\u8bae<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-30\" href=\"https:\/\/finance.ixriver.com\/?p=793\/#%E6%80%BB%E7%BB%93\" title=\"\u603b\u7ed3\">\u603b\u7ed3<\/a><\/li><\/ul><\/li><\/ul><\/nav><\/div>\n<h3><span class=\"ez-toc-section\" id=\"1_%E6%95%B4%E4%BD%93%E6%9E%B6%E6%9E%84%E8%AE%BE%E8%AE%A1\"><\/span>1. \u6574\u4f53\u67b6\u6784\u8bbe\u8ba1<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>\u6df7\u5408\u65b9\u6848\u7684\u6838\u5fc3\u903b\u8f91\u662f\uff1a<strong>\u7528 FEC \u8986\u76d6\u968f\u673a\u7684\u5c0f\u91cf\u4e22\u5305\uff08\u96f6\u5ef6\u8fdf\uff09\uff0c\u7528 ARQ \u8986\u76d6\u5927\u9762\u79ef\u7684\u4e22\u5305\u6216\u7a81\u53d1\u4e22\u5305\uff08\u4f4e\u5e26\u5bbd\u6d88\u8017\uff09\u3002<\/strong><\/p>\n<hr \/>\n<h3><span class=\"ez-toc-section\" id=\"2_%E5%8F%91%E9%80%81%E7%AB%AF_Sender_%E5%AE%9E%E7%8E%B0%E6%B5%81%E7%A8%8B\"><\/span>2. \u53d1\u9001\u7aef (Sender) \u5b9e\u73b0\u6d41\u7a0b<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>\u53d1\u9001\u7aef\u9700\u8981\u7ef4\u62a4\u4e00\u4e2a<strong>\u6ed1\u52a8\u7a97\u53e3\uff08Sliding Window\uff09<\/strong>\uff0c\u7528\u4e8e\u5b58\u50a8\u5df2\u53d1\u9001\u4f46\u5c1a\u672a\u786e\u8ba4\u7684\u5305\u3002<\/p>\n<h4><span class=\"ez-toc-section\" id=\"A_%E5%B0%81%E5%8C%85%E4%B8%8E%E7%BC%93%E5%AD%98\"><\/span><strong>A. \u5c01\u5305\u4e0e\u7f13\u5b58<\/strong><span class=\"ez-toc-section-end\"><\/span><\/h4>\n<ul>\n<li><strong>\u7ed9\u6bcf\u4e2a\u5305\u6253\u4e0a\u5168\u5c40\u552f\u4e00\u7684\u5e8f\u5217\u53f7 (SN)<\/strong>\u3002<\/li>\n<li>\u5c06\u539f\u59cb\u97f3\u9891\u5305\u653e\u5165 <code>Send_Window<\/code> \u7f13\u5b58\uff0c\u7b49\u5f85\u53ef\u80fd\u7684 ARQ \u8bf7\u6c42\u3002<\/li>\n<\/ul>\n<h4><span class=\"ez-toc-section\" id=\"B_FEC_%E7%BC%96%E7%A0%81%E7%AD%96%E7%95%A5\"><\/span><strong>B. FEC \u7f16\u7801\u7b56\u7565<\/strong><span class=\"ez-toc-section-end\"><\/span><\/h4>\n<ul>\n<li><strong>\u5206\u7ec4 (Group)<\/strong>\uff1a\u6bcfK\u4e2a\u539f\u59cb\u5305\u7ec4\u6210\u4e00\u4e2a\u77e9\u9635\u3002<\/li>\n<li><strong>\u8ba1\u7b97 (Encode)<\/strong>\uff1a\u751f\u6210M\u4e2a\u5197\u4f59\u5305\uff08\u901a\u5e38\u4f7f\u7528 Reed-Solomon \u7b97\u6cd5\uff09\u3002<\/li>\n<li><strong>\u52a8\u6001\u5197\u4f59\u7387<\/strong>\uff1a\u6839\u636e\u63a5\u6536\u7aef\u53cd\u9988\u7684\u4e22\u5305\u7387 L\u52a8\u6001\u8c03\u6574M\u7684\u503c\u3002<\/li>\n<li>\u82e5 &#8216;L &lt; 5%&#8217; M=1(\u4f4e\u5197\u4f59)\u3002<\/li>\n<li>\u82e5 &#8216;L &gt; 15%&#8217; M =K*0.4(\u9ad8\u5197\u4f59)\u3002<\/li>\n<\/ul>\n<h4><span class=\"ez-toc-section\" id=\"C_%E5%93%8D%E5%BA%94_ARQ_%E8%AF%B7%E6%B1%82\"><\/span><strong>C. \u54cd\u5e94 ARQ \u8bf7\u6c42<\/strong><span class=\"ez-toc-section-end\"><\/span><\/h4>\n<ul>\n<li>\u76d1\u542c\u6765\u81ea\u63a5\u6536\u7aef\u7684 <code>NACK<\/code> (Negative Acknowledgment) \u5305\u3002<\/li>\n<li>\u4ece <code>Send_Window<\/code> \u4e2d\u68c0\u7d22\u6307\u5b9a\u7684 SN\uff0c\u91cd\u65b0\u6253\u5305\u53d1\u9001\u3002<\/li>\n<li><strong>\u4f18\u5148\u7ea7\u63a7\u5236<\/strong>\uff1aARQ \u7684\u91cd\u4f20\u5305\u4f18\u5148\u7ea7\u5e94\u9ad8\u4e8e\u65b0\u7684 FEC \u5305\u3002<\/li>\n<\/ul>\n<hr \/>\n<h3><span class=\"ez-toc-section\" id=\"3_%E6%8E%A5%E6%94%B6%E7%AB%AF_Receiver_%E5%AE%9E%E7%8E%B0%E6%B5%81%E7%A8%8B\"><\/span>3. \u63a5\u6536\u7aef (Receiver) \u5b9e\u73b0\u6d41\u7a0b<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>\u63a5\u6536\u7aef\u7684\u6838\u5fc3\u662f <strong>Jitter Buffer\uff08\u6296\u52a8\u7f13\u51b2\u533a\uff09<\/strong>\uff0c\u5b83\u8d1f\u8d23\u6392\u5e8f\u3001\u89e3\u7801\u548c\u89e6\u53d1\u8bf7\u6c42\u3002<\/p>\n<h4><span class=\"ez-toc-section\" id=\"A_%E5%A4%84%E7%90%86%E9%80%BB%E8%BE%91%E6%B5%81%E6%B0%B4%E7%BA%BF\"><\/span><strong>A. \u5904\u7406\u903b\u8f91\u6d41\u6c34\u7ebf<\/strong><span class=\"ez-toc-section-end\"><\/span><\/h4>\n<ol>\n<li><strong>\u6536\u5305\u5165\u5e93<\/strong>\uff1a\u6536\u5230\u5305\u540e\u6839\u636e SN \u653e\u5165 Buffer\u3002<\/li>\n<li><strong>FEC \u5c1d\u8bd5\uff08\u5373\u65f6\uff09<\/strong>\uff1a<\/li>\n<li>\u68c0\u67e5\u5f53\u524d\u7ec4 (Group) \u662f\u5426\u6709\u7a7a\u7f3a\u3002<\/li>\n<li>\n<p>\u5982\u679c\u7f3a\u5931\u7684\u5305\u6570\u5c0f\u4e8e\u6536\u5230\u5197\u4f59\u5305\u6570\uff0c\u7acb\u5373\u6267\u884c\u77e9\u9635\u89e3\u7801\uff0c\u6062\u590d\u539f\u59cb\u5305\u3002<\/p>\n<\/li>\n<li>\n<p><strong>ARQ \u89e6\u53d1\uff08\u5b9a\u65f6\/\u95f4\u9699\uff09<\/strong>\uff1a<\/p>\n<\/li>\n<li>\n<p>\u5982\u679c FEC \u65e0\u6cd5\u6062\u590d\uff08\u4e22\u5305\u592a\u591a\uff09\uff0c\u4e14\u65f6\u95f4\u5141\u8bb8\uff08\u5c1a\u672a\u5230\u8fbe\u64ad\u653e\u65f6\u95f4\uff09\uff0c\u53d1\u9001 <code>NACK<\/code> \u7ed9\u53d1\u9001\u7aef\u3002<\/p>\n<\/li>\n<li>\n<p><strong>\u9012\u4ea4\u7ed9\u89e3\u7801\u5668<\/strong>\uff1a<\/p>\n<\/li>\n<li>\u6309 SN \u987a\u5e8f\u53d6\u51fa\u5305\uff0c\u4ea4\u7ed9 Opus\/AAC \u89e3\u7801\u3002<\/li>\n<\/ol>\n<hr \/>\n<h3><span class=\"ez-toc-section\" id=\"4_%E5%85%B3%E9%94%AE%E7%AE%97%E6%B3%95%E4%B8%8E%E5%8D%8F%E8%AE%AE%E7%BB%86%E8%8A%82\"><\/span>4. \u5173\u952e\u7b97\u6cd5\u4e0e\u534f\u8bae\u7ec6\u8282<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<h4><span class=\"ez-toc-section\" id=\"%E6%95%B0%E6%8D%AE%E5%8C%85%E7%BB%93%E6%9E%84%E5%AE%9A%E4%B9%89_C\"><\/span><strong>\u6570\u636e\u5305\u7ed3\u6784\u5b9a\u4e49 (C++)<\/strong><span class=\"ez-toc-section-end\"><\/span><\/h4>\n<pre><code class=\"language-cpp\">enum PacketType { MEDIA = 0, FEC = 1, NACK = 2 };\n\nstruct Packet {\n    uint16_t sn;        \/\/ \u5e8f\u5217\u53f7\n    uint8_t  type;      \/\/ \u5305\u7c7b\u578b\n    uint16_t group_id;  \/\/ FEC \u7ec4 ID\n    uint32_t ts;        \/\/ \u65f6\u95f4\u6233\uff08\u7528\u4e8e\u8ba1\u7b97\u6296\u52a8\uff09\n    uint8_t  payload[MAX_SIZE];\n};\n\n<\/code><\/pre>\n<h4><span class=\"ez-toc-section\" id=\"ARQ_%E7%9A%84%E2%80%9C%E9%99%90%E5%88%B6%E6%80%A7%E7%AD%96%E7%95%A5%E2%80%9D\"><\/span><strong>ARQ \u7684\u201c\u9650\u5236\u6027\u7b56\u7565\u201d<\/strong><span class=\"ez-toc-section-end\"><\/span><\/h4>\n<p>\u5728\u5b9e\u65f6\u97f3\u9891\u4e2d\uff0c\u4e0d\u80fd\u65e0\u9650\u6b21\u91cd\u4f20\u3002<\/p>\n<ul>\n<li><strong>RTT \u5224\u5b9a<\/strong>\uff1a\u5982\u679c (\u5f53\u524d\u65f6\u95f4 &#8211; \u5305\u53d1\u9001\u65f6\u95f4) &gt; 2.5\u500d RTT\uff0c\u901a\u5e38\u653e\u5f03\u91cd\u4f20\u3002<\/li>\n<li><strong>\u8fc7\u671f\u5224\u5b9a<\/strong>\uff1a\u5982\u679c\u5305\u7684 SN \u5df2\u7ecf\u843d\u540e\u4e8e\u5f53\u524d\u64ad\u653e\u6307\u9488\uff0c\u76f4\u63a5\u4e22\u5f03 NACK \u8bf7\u6c42\u3002<\/li>\n<\/ul>\n<hr \/>\n<h3><span class=\"ez-toc-section\" id=\"5_ARQ_%E4%B8%8E_FEC_%E7%9A%84%E5%8D%8F%E5%90%8C%E8%A7%A6%E5%8F%91%E7%AE%97%E6%B3%95\"><\/span>5. ARQ \u4e0e FEC \u7684\u534f\u540c\u89e6\u53d1\u7b97\u6cd5<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>\u5982\u4f55\u5e73\u8861\u4e24\u8005\uff1f\u8fd9\u91cc\u63a8\u8350\u4e00\u4e2a\u5e38\u7528\u7684\u5de5\u4e1a\u7ea7\u903b\u8f91\uff1a<\/p>\n<table>\n<thead>\n<tr>\n<th>\u4e22\u5305\u60c5\u51b5<\/th>\n<th>\u5904\u7406\u7b56\u7565<\/th>\n<th>\u7406\u7531<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td><strong>\u5355\u968f\u673a\u4e22\u5305<\/strong><\/td>\n<td><strong>FEC \u6062\u590d<\/strong><\/td>\n<td>\u5ef6\u8fdf\u4e3a 0\uff0c\u4e0d\u4ea7\u751f\u989d\u5916\u5f80\u8fd4\u65f6\u95f4\u3002<\/td>\n<\/tr>\n<tr>\n<td><strong>\u7a81\u53d1\u4e22\u5305 (Burst)<\/strong><\/td>\n<td><strong>ARQ \u8bf7\u6c42<\/strong><\/td>\n<td>FEC \u96be\u4ee5\u8986\u76d6\u8fde\u7eed 10 \u4e2a\u4ee5\u4e0a\u7684\u4e22\u5305\uff0c\u91cd\u4f20\u66f4\u8282\u7701\u5e26\u5bbd\u3002<\/td>\n<\/tr>\n<tr>\n<td><strong>\u6781\u9ad8 RTT \u7f51\u7edc<\/strong><\/td>\n<td><strong>\u52a0\u5927 FEC \u6743\u91cd<\/strong><\/td>\n<td>RTT \u592a\u5927\uff08\u5982 &gt;300ms\uff09\u65f6\uff0cARQ \u91cd\u4f20\u56de\u6765\u4e5f\u8fc7\u65f6\u4e86\uff0c\u53ea\u80fd\u9760 FEC \u786c\u625b\u3002<\/td>\n<\/tr>\n<tr>\n<td><strong>\u6781\u4f4e\u5e26\u5bbd\u7f51\u7edc<\/strong><\/td>\n<td><strong>\u51cf\u5c0f FEC\uff0c\u5f00\u542f ARQ<\/strong><\/td>\n<td>FEC \u4ea7\u751f\u7684\u5197\u4f59\u6d41\u91cf\u4f1a\u52a0\u5267\u62e5\u585e\uff0cARQ \u6309\u9700\u7d22\u53d6\u66f4\u7cbe\u51c6\u3002<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<hr \/>\n<h3><span class=\"ez-toc-section\" id=\"6_%E5%AE%9E%E7%8E%B0%E5%BB%BA%E8%AE%AE\"><\/span>6. \u5b9e\u73b0\u5efa\u8bae<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<ol>\n<li><strong>\u5f15\u5165 RTT \u4f30\u7b97<\/strong>\uff1a\u4f60\u9700\u8981\u5b9e\u73b0\u7c7b\u4f3c TCP \u7684 RTT \u91c7\u6837\uff08\u901a\u8fc7\u53d1\u9001\u5305\u548c\u63a5\u6536 ACK \u7684\u65f6\u95f4\u5dee\uff09\uff0c\u8fd9\u662f\u5224\u65ad ARQ \u662f\u5426\u8fd8\u6709\u6548\u7684\u524d\u63d0\u3002<\/li>\n<li><strong>\u4f7f\u7528\u6210\u719f\u7684 RS \u5e93<\/strong>\uff1a\u63a8\u8350\u4f7f\u7528 <code>multi-platform FEC library<\/code> (\u5982 <strong>OpenFEC<\/strong>) \u6216 <code>Jerasure<\/code> \u5e93\u5904\u7406\u77e9\u9635\u8fd0\u7b97\uff0c\u4e0d\u8981\u624b\u5199\u6709\u9650\u57df\u7b97\u672f\u3002<\/li>\n<li><strong>\u5e26\u5bbd\u4f30\u7b97 (BWE)<\/strong>\uff1a\u5982\u679c\u53ef\u80fd\uff0c\u96c6\u6210 GCC (Google Congestion Control) \u7b97\u6cd5\uff0c\u5b83\u80fd\u544a\u8bc9\u4f60\u5f53\u524d\u7f51\u7edc\u80fd\u8dd1\u591a\u5c11\u7801\u7387\uff0c\u4ece\u800c\u51b3\u5b9a\u97f3\u9891\u7801\u7387 + FEC \u5197\u4f59\u91cf\u7684\u603b\u548c\u3002<\/li>\n<\/ol>\n<hr \/>\n<h2><span class=\"ez-toc-section\" id=\"WebRTC_%E7%9A%84_ARQ_%E5%92%8C_FEC_%E5%AE%9E%E7%8E%B0%E6%9C%BA%E5%88%B6\"><\/span>WebRTC \u7684 ARQ \u548c FEC \u5b9e\u73b0\u673a\u5236<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>WebRTC \u662f ARQ+FEC \u6df7\u5408\u65b9\u6848\u7684\u5178\u578b\u5b9e\u73b0\uff0c\u5b83\u7efc\u5408\u4f7f\u7528\u4e86\u591a\u79cd\u4e22\u5305\u6062\u590d\u6280\u672f\uff0c\u5b9e\u73b0\u4e86\u4e1a\u754c\u9886\u5148\u7684\u5b9e\u65f6\u901a\u4fe1\u8d28\u91cf\u3002<\/p>\n<h3><span class=\"ez-toc-section\" id=\"WebRTC_ARQ_%E5%AE%9E%E7%8E%B0\"><\/span>WebRTC ARQ \u5b9e\u73b0<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<h4><span class=\"ez-toc-section\" id=\"RTP_NACK%EF%BC%88Negative_Acknowledgment%EF%BC%89\"><\/span>RTP NACK\uff08Negative Acknowledgment\uff09<span class=\"ez-toc-section-end\"><\/span><\/h4>\n<p><strong>\u5b9e\u73b0\u673a\u5236<\/strong>\uff1a<br \/>\n&#8211; <strong>\u534f\u8bae\u57fa\u7840<\/strong>\uff1a\u57fa\u4e8e RTP\/RTCP \u534f\u8bae\uff08RFC 3550\u3001RFC 4585\uff09<br \/>\n&#8211; <strong>\u4e22\u5305\u68c0\u6d4b<\/strong>\uff1a\u63a5\u6536\u7aef\u901a\u8fc7\u5e8f\u5217\u53f7\u95f4\u9699\u68c0\u6d4b\u4e22\u5305<br \/>\n&#8211; <strong>\u53cd\u9988\u673a\u5236<\/strong>\uff1a\u901a\u8fc7 RTCP Feedback \u5305\uff08RTCP NACK\uff09\u901a\u77e5\u53d1\u9001\u7aef<br \/>\n&#8211; <strong>\u6279\u91cf\u8bf7\u6c42<\/strong>\uff1a\u4e00\u6b21 NACK \u53ef\u4ee5\u8bf7\u6c42\u591a\u4e2a\u4e22\u5931\u7684\u5305\uff08\u5e8f\u5217\u53f7\u8303\u56f4\uff09<\/p>\n<p><strong>\u5173\u952e\u53c2\u6570<\/strong>\uff1a<br \/>\n&#8211; <strong>NACK \u95f4\u9694<\/strong>\uff1a\u901a\u5e38\u6bcf 5-20ms \u53d1\u9001\u4e00\u6b21 NACK<br \/>\n&#8211; <strong>\u6700\u5927\u91cd\u4f20\u6b21\u6570<\/strong>\uff1a\u6bcf\u4e2a\u5305\u6700\u591a\u91cd\u4f20 2-3 \u6b21<br \/>\n&#8211; <strong>RTT \u9608\u503c<\/strong>\uff1a\u5982\u679c RTT &gt; 200ms\uff0c\u964d\u4f4e NACK \u9891\u7387\u6216\u7981\u7528<\/p>\n<p><strong>\u5b9e\u73b0\u7ec6\u8282<\/strong>\uff1a<\/p>\n<pre><code class=\"language-cpp\">\/\/ WebRTC NACK \u5305\u7ed3\u6784\uff08\u7b80\u5316\uff09\nstruct RTCPNACK {\n    uint32_t sender_ssrc;      \/\/ \u53d1\u9001\u7aef SSRC\n    uint32_t media_ssrc;        \/\/ \u5a92\u4f53\u6d41 SSRC\n    uint16_t pid;              \/\/ \u7b2c\u4e00\u4e2a\u4e22\u5931\u5305\u7684\u5e8f\u5217\u53f7\n    uint16_t blp;              \/\/ Bitmask\uff0c\u8868\u793a\u540e\u7eed\u4e22\u5931\u7684\u5305\n};\n<\/code><\/pre>\n<h4><span class=\"ez-toc-section\" id=\"RTX%EF%BC%88RTP_Retransmission%EF%BC%89\"><\/span>RTX\uff08RTP Retransmission\uff09<span class=\"ez-toc-section-end\"><\/span><\/h4>\n<p><strong>\u5b9e\u73b0\u673a\u5236<\/strong>\uff1a<br \/>\n&#8211; <strong>\u72ec\u7acb\u6d41<\/strong>\uff1a\u4f7f\u7528\u72ec\u7acb\u7684 RTP \u6d41\uff08RTX \u6d41\uff09\u4f20\u8f93\u91cd\u4f20\u5305<br \/>\n&#8211; <strong>SSRC \u5206\u79bb<\/strong>\uff1a\u539f\u59cb\u6d41\u548c\u91cd\u4f20\u6d41\u4f7f\u7528\u4e0d\u540c\u7684 SSRC<br \/>\n&#8211; <strong>\u5e8f\u5217\u53f7\u6620\u5c04<\/strong>\uff1a\u91cd\u4f20\u5305\u4f7f\u7528 RTX \u5e8f\u5217\u53f7\uff0c\u901a\u8fc7 RTP Header Extension \u643a\u5e26\u539f\u59cb\u5e8f\u5217\u53f7<\/p>\n<p><strong>\u4f18\u52bf<\/strong>\uff1a<br \/>\n&#8211; \u53ef\u4ee5\u533a\u5206\u539f\u59cb\u5305\u548c\u91cd\u4f20\u5305\uff0c\u4fbf\u4e8e\u7edf\u8ba1\u548c\u76d1\u63a7<br \/>\n&#8211; \u652f\u6301\u4e0d\u540c\u7684\u4f20\u8f93\u4f18\u5148\u7ea7<br \/>\n&#8211; \u517c\u5bb9\u6027\u66f4\u597d\uff0c\u7b26\u5408 RTP \u6807\u51c6<\/p>\n<p><strong>\u5b9e\u73b0\u7ec6\u8282<\/strong>\uff1a<\/p>\n<pre><code class=\"language-cpp\">\/\/ RTX \u5305\u7ed3\u6784\nstruct RTXPacket {\n    uint16_t rtx_seq;          \/\/ RTX \u6d41\u5e8f\u5217\u53f7\n    uint16_t original_seq;     \/\/ \u539f\u59cb\u5e8f\u5217\u53f7\uff08\u901a\u8fc7 Header Extension\uff09\n    uint8_t  payload[];\n};\n<\/code><\/pre>\n<h4><span class=\"ez-toc-section\" id=\"NACK_%E8%A7%A6%E5%8F%91%E7%AD%96%E7%95%A5\"><\/span>NACK \u89e6\u53d1\u7b56\u7565<span class=\"ez-toc-section-end\"><\/span><\/h4>\n<p><strong>\u89e6\u53d1\u6761\u4ef6<\/strong>\uff1a<br \/>\n1. <strong>\u5e8f\u5217\u53f7\u95f4\u9699\u68c0\u6d4b<\/strong>\uff1a\u53d1\u73b0\u5e8f\u5217\u53f7\u4e0d\u8fde\u7eed<br \/>\n2. <strong>\u5b9a\u65f6\u89e6\u53d1<\/strong>\uff1a\u6bcf 5-20ms \u68c0\u67e5\u4e00\u6b21\uff0c\u6279\u91cf\u53d1\u9001 NACK<br \/>\n3. <strong>RTT \u5224\u65ad<\/strong>\uff1a\u5982\u679c RTT \u8fc7\u5927\uff0c\u53ef\u80fd\u653e\u5f03 NACK<\/p>\n<p><strong>\u4f18\u5316\u7b56\u7565<\/strong>\uff1a<br \/>\n&#8211; <strong>\u5ef6\u8fdf\u53d1\u9001<\/strong>\uff1a\u7b49\u5f85\u4e00\u5c0f\u6bb5\u65f6\u95f4\uff085-10ms\uff09\uff0c\u53ef\u80fd\u6536\u5230\u4e71\u5e8f\u5305<br \/>\n&#8211; <strong>\u6279\u91cf\u5904\u7406<\/strong>\uff1a\u4e00\u6b21 NACK \u8bf7\u6c42\u591a\u4e2a\u4e22\u5931\u7684\u5305<br \/>\n&#8211; <strong>\u4f18\u5148\u7ea7\u63a7\u5236<\/strong>\uff1a\u5173\u952e\u5e27\uff08I\u5e27\uff09\u4f18\u5148\u91cd\u4f20<\/p>\n<h3><span class=\"ez-toc-section\" id=\"WebRTC_FEC_%E5%AE%9E%E7%8E%B0\"><\/span>WebRTC FEC \u5b9e\u73b0<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<h4><span class=\"ez-toc-section\" id=\"ULPFEC%EF%BC%88Uneven_Level_Protection_FEC%EF%BC%89\"><\/span>ULPFEC\uff08Uneven Level Protection FEC\uff09<span class=\"ez-toc-section-end\"><\/span><\/h4>\n<p><strong>\u5b9e\u73b0\u673a\u5236<\/strong>\uff1a<br \/>\n&#8211; <strong>\u534f\u8bae\u6807\u51c6<\/strong>\uff1aRFC 5109<br \/>\n&#8211; <strong>\u7f16\u7801\u7b97\u6cd5<\/strong>\uff1a\u57fa\u4e8e XOR \u8fd0\u7b97\u7684\u7b80\u5355 FEC<br \/>\n&#8211; <strong>\u4fdd\u62a4\u6a21\u5f0f<\/strong>\uff1a\u53ef\u4ee5\u4fdd\u62a4\u591a\u4e2a RTP \u5305\uff08\u901a\u5e38 2-8 \u4e2a\uff09<br \/>\n&#8211; <strong>\u591a\u7ea7\u4fdd\u62a4<\/strong>\uff1a\u4e0d\u540c\u91cd\u8981\u6027\u7684\u5305\u53ef\u4ee5\u4f7f\u7528\u4e0d\u540c\u7684 FEC \u4fdd\u62a4\u7ea7\u522b<\/p>\n<p><strong>\u7f16\u7801\u8fc7\u7a0b<\/strong>\uff1a<br \/>\n1. <strong>\u5206\u7ec4<\/strong>\uff1a\u5c06\u8fde\u7eed\u7684 K \u4e2a\u5a92\u4f53\u5305\u5206\u4e3a\u4e00\u7ec4<br \/>\n2. <strong>\u7f16\u7801<\/strong>\uff1a\u5bf9\u8fd9 K \u4e2a\u5305\u8fdb\u884c XOR \u8fd0\u7b97\uff0c\u751f\u6210 FEC \u5305<br \/>\n3. <strong>\u53d1\u9001<\/strong>\uff1a\u5a92\u4f53\u5305\u548c FEC \u5305\u4e00\u8d77\u53d1\u9001<\/p>\n<p><strong>\u89e3\u7801\u8fc7\u7a0b<\/strong>\uff1a<br \/>\n1. <strong>\u68c0\u6d4b\u4e22\u5305<\/strong>\uff1a\u68c0\u67e5\u7ec4\u5185\u662f\u5426\u6709\u5305\u4e22\u5931<br \/>\n2. <strong>\u5224\u65ad\u53ef\u6062\u590d\u6027<\/strong>\uff1a\u5982\u679c\u4e22\u5931\u5305\u6570 \u2264 FEC \u5305\u6570\uff0c\u53ef\u4ee5\u6062\u590d<br \/>\n3. <strong>XOR \u89e3\u7801<\/strong>\uff1a\u4f7f\u7528\u6536\u5230\u7684\u5305\u548c FEC \u5305\u8fdb\u884c XOR \u8fd0\u7b97\u6062\u590d\u4e22\u5931\u7684\u5305<\/p>\n<p><strong>\u5173\u952e\u53c2\u6570<\/strong>\uff1a<br \/>\n&#8211; <strong>\u4fdd\u62a4\u5305\u6570<\/strong>\uff1a\u901a\u5e38\u4fdd\u62a4 2-8 \u4e2a\u5305<br \/>\n&#8211; <strong>\u5197\u4f59\u7387<\/strong>\uff1a\u6839\u636e\u4e22\u5305\u7387\u52a8\u6001\u8c03\u6574\uff085%-40%\uff09<br \/>\n&#8211; <strong>\u5ef6\u8fdf<\/strong>\uff1a\u96f6\u5ef6\u8fdf\uff0c\u65e0\u9700\u7b49\u5f85\u5f80\u8fd4\u65f6\u95f4<\/p>\n<h4><span class=\"ez-toc-section\" id=\"FlexFEC\"><\/span>FlexFEC<span class=\"ez-toc-section-end\"><\/span><\/h4>\n<p><strong>\u5b9e\u73b0\u673a\u5236<\/strong>\uff1a<br \/>\n&#8211; <strong>\u534f\u8bae\u6807\u51c6<\/strong>\uff1aRFC 8627<br \/>\n&#8211; <strong>\u7f16\u7801\u7b97\u6cd5<\/strong>\uff1a\u652f\u6301\u591a\u79cd\u7f16\u7801\u65b9\u5f0f\uff08XOR\u3001Reed-Solomon \u7b49\uff09<br \/>\n&#8211; <strong>\u4fdd\u62a4\u6a21\u5f0f<\/strong>\uff1a\u652f\u6301 1D\uff08\u4e00\u7ef4\uff09\u548c 2D\uff08\u4e8c\u7ef4\uff09\u4fdd\u62a4\u6a21\u5f0f<br \/>\n&#8211; <strong>\u7075\u6d3b\u6027<\/strong>\uff1a\u53ef\u4ee5\u7075\u6d3b\u914d\u7f6e\u4fdd\u62a4\u53c2\u6570<\/p>\n<p><strong>1D \u4fdd\u62a4\u6a21\u5f0f<\/strong>\uff1a<br \/>\n&#8211; \u5bf9\u8fde\u7eed\u7684\u5305\u8fdb\u884c\u4e00\u7ef4\u4fdd\u62a4<br \/>\n&#8211; \u9002\u5408\u968f\u673a\u4e22\u5305\u573a\u666f<\/p>\n<p><strong>2D \u4fdd\u62a4\u6a21\u5f0f<\/strong>\uff1a<br \/>\n&#8211; \u5bf9\u5305\u77e9\u9635\u8fdb\u884c\u4e8c\u7ef4\u4fdd\u62a4<br \/>\n&#8211; \u53ef\u4ee5\u540c\u65f6\u4fdd\u62a4\u884c\u548c\u5217<br \/>\n&#8211; \u9002\u5408\u7a81\u53d1\u4e22\u5305\u573a\u666f<\/p>\n<p><strong>\u914d\u7f6e\u793a\u4f8b<\/strong>\uff1a<\/p>\n<pre><code class=\"language-cpp\">\/\/ FlexFEC \u914d\u7f6e\nstruct FlexFECConfig {\n    uint8_t  protection_mode;   \/\/ 1D \u6216 2D\n    uint8_t  row_k;              \/\/ \u884c\u4fdd\u62a4\u5305\u6570\n    uint8_t  row_n;              \/\/ \u884c\u603b\u5305\u6570\n    uint8_t  col_k;              \/\/ \u5217\u4fdd\u62a4\u5305\u6570\uff082D\u6a21\u5f0f\uff09\n    uint8_t  col_n;              \/\/ \u5217\u603b\u5305\u6570\uff082D\u6a21\u5f0f\uff09\n};\n<\/code><\/pre>\n<h3><span class=\"ez-toc-section\" id=\"WebRTC_%E5%8D%8F%E5%90%8C%E6%9C%BA%E5%88%B6\"><\/span>WebRTC \u534f\u540c\u673a\u5236<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<h4><span class=\"ez-toc-section\" id=\"%E8%87%AA%E9%80%82%E5%BA%94%E7%AD%96%E7%95%A5\"><\/span>\u81ea\u9002\u5e94\u7b56\u7565<span class=\"ez-toc-section-end\"><\/span><\/h4>\n<p>WebRTC \u6839\u636e\u7f51\u7edc\u72b6\u51b5\u52a8\u6001\u8c03\u6574 ARQ \u548c FEC \u7684\u4f7f\u7528\uff1a<\/p>\n<p><strong>\u7f51\u7edc\u8d28\u91cf\u597d\uff08\u4e22\u5305\u7387 &lt; 2%\uff09<\/strong>\uff1a<br \/>\n&#8211; \u964d\u4f4e FEC \u5197\u4f59\u5ea6\uff085-10%\uff09<br \/>\n&#8211; \u4e3b\u8981\u4f9d\u8d56 NACK \u91cd\u4f20<br \/>\n&#8211; \u51cf\u5c11\u5e26\u5bbd\u5f00\u9500<\/p>\n<p><strong>\u7f51\u7edc\u8d28\u91cf\u4e2d\u7b49\uff08\u4e22\u5305\u7387 2-10%\uff09<\/strong>\uff1a<br \/>\n&#8211; \u4e2d\u7b49 FEC \u5197\u4f59\u5ea6\uff0815-25%\uff09<br \/>\n&#8211; NACK + FEC \u7ec4\u5408\u4f7f\u7528<br \/>\n&#8211; \u5e73\u8861\u5ef6\u8fdf\u548c\u5e26\u5bbd<\/p>\n<p><strong>\u7f51\u7edc\u8d28\u91cf\u5dee\uff08\u4e22\u5305\u7387 &gt; 10%\uff09<\/strong>\uff1a<br \/>\n&#8211; \u63d0\u9ad8 FEC \u5197\u4f59\u5ea6\uff0830-40%\uff09<br \/>\n&#8211; \u5982\u679c RTT \u9ad8\uff0c\u51cf\u5c11 NACK \u4f9d\u8d56<br \/>\n&#8211; \u4f18\u5148\u4fdd\u8bc1\u6d41\u7545\u5ea6<\/p>\n<h4><span class=\"ez-toc-section\" id=\"RTT_%E8%87%AA%E9%80%82%E5%BA%94\"><\/span>RTT \u81ea\u9002\u5e94<span class=\"ez-toc-section-end\"><\/span><\/h4>\n<p><strong>\u4f4e RTT\uff08&lt; 50ms\uff09<\/strong>\uff1a<br \/>\n&#8211; \u4f18\u5148\u4f7f\u7528 NACK\uff0c\u5ef6\u8fdf\u4f4e<br \/>\n&#8211; FEC \u5197\u4f59\u5ea6\u8f83\u4f4e<\/p>\n<p><strong>\u4e2d\u7b49 RTT\uff0850-200ms\uff09<\/strong>\uff1a<br \/>\n&#8211; NACK + FEC \u7ec4\u5408<br \/>\n&#8211; \u6839\u636e RTT \u8c03\u6574 NACK \u8d85\u65f6\u65f6\u95f4<\/p>\n<p><strong>\u9ad8 RTT\uff08&gt; 200ms\uff09<\/strong>\uff1a<br \/>\n&#8211; \u4e3b\u8981\u4f9d\u8d56 FEC<br \/>\n&#8211; \u51cf\u5c11\u6216\u7981\u7528 NACK\uff08\u91cd\u4f20\u56de\u6765\u4e5f\u8fc7\u65f6\u4e86\uff09<\/p>\n<h4><span class=\"ez-toc-section\" id=\"%E5%B8%A6%E5%AE%BD%E8%87%AA%E9%80%82%E5%BA%94\"><\/span>\u5e26\u5bbd\u81ea\u9002\u5e94<span class=\"ez-toc-section-end\"><\/span><\/h4>\n<p><strong>\u5e26\u5bbd\u5145\u8db3<\/strong>\uff1a<br \/>\n&#8211; \u53ef\u4ee5\u4f7f\u7528\u8f83\u9ad8\u7684 FEC \u5197\u4f59\u5ea6<br \/>\n&#8211; \u4fdd\u8bc1\u66f4\u597d\u7684\u8d28\u91cf<\/p>\n<p><strong>\u5e26\u5bbd\u53d7\u9650<\/strong>\uff1a<br \/>\n&#8211; \u964d\u4f4e FEC \u5197\u4f59\u5ea6<br \/>\n&#8211; \u4f18\u5148\u4f7f\u7528 NACK\uff08\u6309\u9700\u91cd\u4f20\uff09<br \/>\n&#8211; \u6839\u636e\u5e26\u5bbd\u4f30\u7b97\uff08BWE\uff09\u8c03\u6574\u7801\u7387\u548c\u5197\u4f59\u5ea6<\/p>\n<h3><span class=\"ez-toc-section\" id=\"WebRTC_%E5%85%B3%E9%94%AE%E5%AE%9E%E7%8E%B0%E7%BB%86%E8%8A%82\"><\/span>WebRTC \u5173\u952e\u5b9e\u73b0\u7ec6\u8282<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<h4><span class=\"ez-toc-section\" id=\"%E5%8F%91%E9%80%81%E7%AB%AF%E5%AE%9E%E7%8E%B0\"><\/span>\u53d1\u9001\u7aef\u5b9e\u73b0<span class=\"ez-toc-section-end\"><\/span><\/h4>\n<p><strong>\u5305\u53d1\u9001\u6d41\u7a0b<\/strong>\uff1a<br \/>\n1. <strong>\u5a92\u4f53\u5305\u53d1\u9001<\/strong>\uff1a\u53d1\u9001\u539f\u59cb\u5a92\u4f53\u5305\uff0c\u8bb0\u5f55\u5230\u53d1\u9001\u7a97\u53e3<br \/>\n2. <strong>FEC \u7f16\u7801<\/strong>\uff1a\u5bf9\u5a92\u4f53\u5305\u8fdb\u884c FEC \u7f16\u7801\uff0c\u751f\u6210\u5197\u4f59\u5305<br \/>\n3. <strong>FEC \u5305\u53d1\u9001<\/strong>\uff1a\u53d1\u9001 FEC \u5305<br \/>\n4. <strong>NACK \u5904\u7406<\/strong>\uff1a\u6536\u5230 NACK \u540e\uff0c\u901a\u8fc7 RTX \u6d41\u91cd\u4f20<\/p>\n<p><strong>\u4f18\u5148\u7ea7\u63a7\u5236<\/strong>\uff1a<br \/>\n&#8211; RTX \u91cd\u4f20\u5305\u4f18\u5148\u7ea7\u6700\u9ad8<br \/>\n&#8211; \u5173\u952e\u5e27\uff08I\u5e27\uff09\u4f18\u5148\u7ea7\u9ad8\u4e8e\u666e\u901a\u5e27<br \/>\n&#8211; FEC \u5305\u4f18\u5148\u7ea7\u4f4e\u4e8e\u5a92\u4f53\u5305<\/p>\n<h4><span class=\"ez-toc-section\" id=\"%E6%8E%A5%E6%94%B6%E7%AB%AF%E5%AE%9E%E7%8E%B0\"><\/span>\u63a5\u6536\u7aef\u5b9e\u73b0<span class=\"ez-toc-section-end\"><\/span><\/h4>\n<p><strong>\u5305\u63a5\u6536\u6d41\u7a0b<\/strong>\uff1a<br \/>\n1. <strong>\u5305\u63a5\u6536<\/strong>\uff1a\u6536\u5230\u5305\u540e\u653e\u5165 Jitter Buffer<br \/>\n2. <strong>FEC \u5c1d\u8bd5<\/strong>\uff1a\u7acb\u5373\u5c1d\u8bd5\u4f7f\u7528 FEC \u6062\u590d\u4e22\u5305<br \/>\n3. <strong>NACK \u89e6\u53d1<\/strong>\uff1a\u5982\u679c FEC \u65e0\u6cd5\u6062\u590d\uff0c\u4e14\u65f6\u95f4\u5141\u8bb8\uff0c\u53d1\u9001 NACK<br \/>\n4. <strong>\u5305\u6392\u5e8f<\/strong>\uff1a\u6309\u5e8f\u5217\u53f7\u6392\u5e8f\uff0c\u9012\u4ea4\u7ed9\u89e3\u7801\u5668<\/p>\n<p><strong>Jitter Buffer \u7ba1\u7406<\/strong>\uff1a<br \/>\n&#8211; <strong>\u6700\u5c0f\u5ef6\u8fdf<\/strong>\uff1a\u901a\u5e38 30-50ms<br \/>\n&#8211; <strong>\u6700\u5927\u5ef6\u8fdf<\/strong>\uff1a\u6839\u636e\u7f51\u7edc\u72b6\u51b5\u52a8\u6001\u8c03\u6574\uff0850-200ms\uff09<br \/>\n&#8211; <strong>\u5305\u8fc7\u671f<\/strong>\uff1a\u8d85\u8fc7\u64ad\u653e\u65f6\u95f4\u7684\u5305\u76f4\u63a5\u4e22\u5f03<\/p>\n<h4><span class=\"ez-toc-section\" id=\"%E7%BB%9F%E8%AE%A1%E5%92%8C%E5%8F%8D%E9%A6%88\"><\/span>\u7edf\u8ba1\u548c\u53cd\u9988<span class=\"ez-toc-section-end\"><\/span><\/h4>\n<p><strong>\u5173\u952e\u6307\u6807<\/strong>\uff1a<br \/>\n&#8211; <strong>\u4e22\u5305\u7387<\/strong>\uff1a\u901a\u8fc7 RTCP Receiver Report \u53cd\u9988<br \/>\n&#8211; <strong>RTT<\/strong>\uff1a\u901a\u8fc7 RTCP Sender Report \u548c Receiver Report \u8ba1\u7b97<br \/>\n&#8211; <strong>\u5e26\u5bbd\u4f30\u7b97<\/strong>\uff1a\u4f7f\u7528 GCC\uff08Google Congestion Control\uff09\u7b97\u6cd5<\/p>\n<p><strong>\u53cd\u9988\u673a\u5236<\/strong>\uff1a<br \/>\n&#8211; <strong>RTCP RR<\/strong>\uff1a\u63a5\u6536\u7aef\u62a5\u544a\uff0c\u5305\u542b\u4e22\u5305\u7387\u3001\u5ef6\u8fdf\u7b49\u4fe1\u606f<br \/>\n&#8211; <strong>RTCP NACK<\/strong>\uff1a\u4e22\u5305\u91cd\u4f20\u8bf7\u6c42<br \/>\n&#8211; <strong>RTCP PLI\/FIR<\/strong>\uff1a\u5173\u952e\u5e27\u8bf7\u6c42<\/p>\n<h3><span class=\"ez-toc-section\" id=\"WebRTC_%E9%85%8D%E7%BD%AE%E5%BB%BA%E8%AE%AE\"><\/span>WebRTC \u914d\u7f6e\u5efa\u8bae<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p><strong>\u89c6\u9891\u901a\u8bdd\u573a\u666f<\/strong>\uff1a<br \/>\n&#8211; <strong>FEC \u5197\u4f59\u5ea6<\/strong>\uff1a15-25%<br \/>\n&#8211; <strong>NACK \u542f\u7528<\/strong>\uff1a\u662f<br \/>\n&#8211; <strong>RTX \u542f\u7528<\/strong>\uff1a\u662f<br \/>\n&#8211; <strong>\u4fdd\u62a4\u6a21\u5f0f<\/strong>\uff1aULPFEC \u6216 FlexFEC 1D<\/p>\n<p><strong>\u76f4\u64ad\u63a8\u6d41\u573a\u666f<\/strong>\uff1a<br \/>\n&#8211; <strong>FEC \u5197\u4f59\u5ea6<\/strong>\uff1a20-30%<br \/>\n&#8211; <strong>NACK \u542f\u7528<\/strong>\uff1a\u6839\u636e\u5ef6\u8fdf\u8981\u6c42\uff08\u4f4e\u5ef6\u8fdf\u542f\u7528\uff0c\u9ad8\u5ef6\u8fdf\u7981\u7528\uff09<br \/>\n&#8211; <strong>\u4fdd\u62a4\u6a21\u5f0f<\/strong>\uff1aFlexFEC 2D\uff08\u9002\u5408\u7a81\u53d1\u4e22\u5305\uff09<\/p>\n<p><strong>\u70b9\u64ad\u573a\u666f<\/strong>\uff1a<br \/>\n&#8211; <strong>FEC \u5197\u4f59\u5ea6<\/strong>\uff1a10-15%<br \/>\n&#8211; <strong>NACK \u542f\u7528<\/strong>\uff1a\u662f\uff08\u5ef6\u8fdf\u8981\u6c42\u4e0d\u4e25\u683c\uff09<br \/>\n&#8211; <strong>\u4fdd\u62a4\u6a21\u5f0f<\/strong>\uff1aULPFEC<\/p>\n<h3><span class=\"ez-toc-section\" id=\"%E6%80%BB%E7%BB%93\"><\/span>\u603b\u7ed3<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>WebRTC \u7684 ARQ+FEC \u6df7\u5408\u65b9\u6848\u901a\u8fc7\u4ee5\u4e0b\u673a\u5236\u5b9e\u73b0\u4e86\u9ad8\u6548\u7684\u4e22\u5305\u6062\u590d\uff1a<\/p>\n<ol>\n<li><strong>\u591a\u5c42\u6b21\u7684 ARQ<\/strong>\uff1aNACK + RTX\uff0c\u5b9e\u73b0\u5feb\u901f\u91cd\u4f20<\/li>\n<li><strong>\u7075\u6d3b\u7684 FEC<\/strong>\uff1aULPFEC + FlexFEC\uff0c\u652f\u6301\u591a\u79cd\u4fdd\u62a4\u6a21\u5f0f<\/li>\n<li><strong>\u81ea\u9002\u5e94\u7b56\u7565<\/strong>\uff1a\u6839\u636e\u7f51\u7edc\u72b6\u51b5\u52a8\u6001\u8c03\u6574 ARQ \u548c FEC \u7684\u6bd4\u4f8b<\/li>\n<li><strong>\u4f18\u5148\u7ea7\u63a7\u5236<\/strong>\uff1a\u5173\u952e\u6570\u636e\u4f18\u5148\u4fdd\u62a4\uff0c\u4fdd\u8bc1\u7528\u6237\u4f53\u9a8c<\/li>\n<li><strong>\u5b8c\u5584\u7684\u53cd\u9988\u673a\u5236<\/strong>\uff1a\u901a\u8fc7 RTCP \u5b9e\u73b0\u7f51\u7edc\u72b6\u51b5\u7684\u5b9e\u65f6\u53cd\u9988<\/li>\n<\/ol>\n<p>\u8fd9\u4f7f\u5f97 WebRTC \u80fd\u591f\u5728\u5404\u79cd\u7f51\u7edc\u6761\u4ef6\u4e0b\u63d0\u4f9b\u7a33\u5b9a\u3001\u4f4e\u5ef6\u8fdf\u7684\u5b9e\u65f6\u901a\u4fe1\u4f53\u9a8c\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u5728\u5e95\u5c42 UDP \u4f20\u8f93\u534f\u8bae\u4e2d\uff0c\u5355\u7eaf\u4f9d\u9760 FEC\uff08\u524d\u5411\u7ea0\u9519\uff09\u4f1a\u6d6a\u8d39\u5e26\u5bbd\uff0c\u5355\u7eaf\u4f9d\u9760 ARQ\uff08\u4e22\u5305\u91cd\u4f20\uff09\u4f1a\u5e26\u6765\u5de8\u5927\u7684\u5ef6 [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[28],"tags":[],"blocksy_meta":[],"featured_image_urls":{"full":"","thumbnail":"","medium":"","medium_large":"","large":"","1536x1536":"","2048x2048":""},"post_excerpt_stackable":"<p>\u5728\u5e95\u5c42 UDP \u4f20\u8f93\u534f\u8bae\u4e2d\uff0c\u5355\u7eaf\u4f9d\u9760 FEC\uff08\u524d\u5411\u7ea0\u9519\uff09\u4f1a\u6d6a\u8d39\u5e26\u5bbd\uff0c\u5355\u7eaf\u4f9d\u9760 ARQ\uff08\u4e22\u5305\u91cd\u4f20\uff09\u4f1a\u5e26\u6765\u5de8\u5927\u7684\u5ef6\u8fdf\u3002ARQ+FEC \u6df7\u5408\u65b9\u6848\uff08Hybrid ARQ\uff09 \u662f\u76ee\u524d\u5b9e\u65f6\u97f3\u89c6\u9891\u901a\u4fe1\uff08\u5982 WebRT&hellip;<\/p>\n","category_list":"<a href=\"https:\/\/finance.ixriver.com\/?cat=28\" rel=\"category\">\u89c6\u9891<\/a>","author_info":{"name":"admin","url":"https:\/\/finance.ixriver.com\/?author=1"},"comments_num":"0 comments","_links":{"self":[{"href":"https:\/\/finance.ixriver.com\/index.php?rest_route=\/wp\/v2\/posts\/793"}],"collection":[{"href":"https:\/\/finance.ixriver.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/finance.ixriver.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/finance.ixriver.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/finance.ixriver.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=793"}],"version-history":[{"count":0,"href":"https:\/\/finance.ixriver.com\/index.php?rest_route=\/wp\/v2\/posts\/793\/revisions"}],"wp:attachment":[{"href":"https:\/\/finance.ixriver.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=793"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/finance.ixriver.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=793"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/finance.ixriver.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=793"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}