On the problem of videoJs playing rtmp in the local environment

1. Write a demo post that can be played in web, but if you open it directly in a browser, you can"t
2.

<html>  
  <head>  
  <title></title>  
  <meta charset="utf-8">  
  <link href="http://vjs.zencdn.net/5.5.3/video-js.css" rel="stylesheet">  
  <!-- If you"d like to support IE8 -->  
  <script src="http://vjs.zencdn.net/ie8/1.1.1/videojs-ie8.min.js"></script>  
</head>  
<body>  
  <h1></h1>  
 <video id="my-video" class="video-js" controls preload="auto" width="640" height="300"  
 poster="https://img.codeshelper.com/upload/img/2021/08/23/lxpa4qyndqx1103.jpg" data-setup="{}">  
    <source src="rtmp://live.hkstv.hk.lxdns.com/live/hks" type="rtmp/flv">  
    <!-- rtmphls -->  
    <!-- <source src="http://10.10.5.119/live/livestream.m3u8" type="application/x-mpegURL"> -->  
    <p class="vjs-no-js"> JavaScriptHTML5  
      To view this video please enable JavaScript, and consider upgrading to a web browser that  
      <a href="http://videojs.com/html5-video-support/" target="_blank">supports HTML5 video</a>  
      
 </video>  
 <script src="http://vjs.zencdn.net/5.5.3/video.js"></script>  
</body>  
</html>

there is no error message
try to change to a file like map4, which can be played directly, but there is no result.

ask the great god to explain why you can"t play it directly in the browser