前端视频截图的方法
<video id="video" controls width="500" height="200" autoplay>
<source src="http://vjs.zencdn.net/v/oceans.mp4" type='video/mp4'>
<source src="http://vjs.zencdn.net/v/oceans.mp4" type='video/ogg'>
<source src="http://vjs.zencdn.net/v/oceans.mp4" type='video/webm'>
</video>
<canvas id="myCanvas"></canvas>
<script>
var myCanvas = document.getElementById('myCanvas');
var c = myCanvas.getContext("2d")
var video = document.getElementById('video');
setTimeout(() => {
myCanvas.height = video.height
myCanvas.width = video.width
//在画布上定位图像，并规定图像的宽度和高度：
c.drawImage(video, 0, 0, myCanvas.width, myCanvas.height)
}, 3000);
</script>
