canvas绘制视频
代码语言：javascript
复制<html>
<head>
<style>
body {
background: black;
color:#CCCCCC;
}
#c2 {
background-image: url(test.png);
background-repeat: no-repeat;
}
div {
float: left;
border :1px solid #444444;
padding:10px;
margin: 10px;
background:#3B3B3B;
}
</style>
<script type="text/javascript">
function p(){
this.doLoad = function doLoad() {
this.video = document.getElementById('video');
this.c1 = document.getElementById('c1');
this.ctx1 = this.c1.getContext('2d');
this.c2 = document.getElementById('c2');
this.ctx2 = this.c2.getContext('2d');
let self = this;
this.video.addEventListener('play', function() {
self.width = self.video.videoWidth / 2;
self.height = self.video.vi
