How to center HTML5 Videos?

HTML CODE:

<div>
 <video class="center" src="https://stackoverflow.com/questions/5879209/vd/vd1.mp4" controls poster="dossierimage/imagex.jpg" width="600"></video>
</div>

CSS CODE:

.center {
    margin-left: auto;
    margin-right: auto;
    display: block
}