这是HTML5中Canvas技术与Video技术结合的实例。效果图：
以下代码不能运行，只提供学习查看。若想预览该实例请浏览http://html5demos.com/video-canvas
（浏览器支持：只支持Safari, Firefox）
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8" />
<title>Dizzy</title>
<style>
* { margin: 0;}
body { font-family: helvetica; padding: 10px; }
input { width: 50px; }
/*video, canvas { display: block; }*/
p { margin-top: 20px;}
</style>
</head>
<body>
<video height="360" width="480">
<source src="dizzy.mp4" />
<source src="dizzy.ogv" />
</video><canvas></canvas>
<p>
<input type="button" id="play" value="play">
<span id="position">00:00</span> / <span id="duration"></span>
</p>
var video = document.querySelector('video');
var togglePlay = document.querySelector('#play');
var position = document.querySelector('#position');
var canvas = document.querySelector('canvas');
var ctx = canvas.getContext('2d');
addEvent(togglePlay, 'click', function () {
video.playbackRate = 0.5;
if (video.paused) {
if (video.ended) video.currentTime = 0;
video.play();
this.value = "pause";
} else {
video.pause();
this.value = "play";
}
});
addEvent(video, 'timeupdate', function () {
position.innerHTML = asTime(this.currentTime);
// ctx.restore();
ctx.drawImage(video, 0, 0, video.width, video.height, 0, 0, canvas.width, canvas.height);
});
addEvent(video, 'ended', function () {
togglePlay.value = "play";
});
addEvent(video, 'canplay', function () {
video.muted = true;
document.querySelector('#duration').innerHTML = asTime(this.duration);
startCanvas();
});
function startCanvas() {
canvas.setAttribute('height', Math.floor(video.height));
canvas.setAttribute('width', Math.floor(video.width));
ctx.translate(canvas.width/2, canvas.height/2);
ctx.scale(-1, 1);
ctx.translate(-canvas.width/2, -canvas.height/2);
ctx.drawImage(video, 0, 0, video.width, video.height, 0, 0, canvas.width, canvas.height);
// var mirror = canvas.height * 0.6;
// var grad = ctx.createLinearGradient(0, 0, 0, mirror);
// grad.addColorStop(0, 'rgba(0, 0, 0, 0.5)');
// grad.addColorStop(1, 'rgba(0, 0, 0, 1)');
// ctx.fillStyle = grad;
// ctx.rect(0, 0, canvas.width, mirror);
// ctx.fill();
// ctx.save();
}
function asTime(t) {
t = Math.round(t);
var s = t % 60;
var m = Math.round(t / 60);
return two(m) + ':' + two(s);
}
function two(s) {
s += "";
if (s.length < 2) s = "0" + s;
return s;
}
</body>
</html>