html视频加封面怎么弄呀？播放前视频封面图怎么加。

如标题想html视频加封面图片。就是播放前视频静态图片。如何加上，视屏代码如下。
!DOCTYPE html
html
head
meta charset="utf-8"
/head
body
div align="center"
video width="320" height="240" controls
source src="视频地址" type="video/mp4"
/video
/div
/body
/html


<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
  </head>
  <body>
    <video
      src="https://vjs.zencdn.net/v/oceans.mp4"
      poster="https://img-blog.csdnimg.cn/606bf84e532e46438d57ce057d361f32.png"
      width="500"
      height="300"
      controls
    ></video>
  </body>
</html>