JSFiddle - React, Tailwind, and code Playground

HTML

<h3>No Rounded Corners in WebKit :(</h3>
<div class="rc">
    <video src="http://mirrorblender.top-ix.org/peach/bigbuckbunny_movies/big_buck_bunny_480p_stereo.ogg"  height="180"></video>
</div>

CSS

.rc{
    width:320px;
    -moz-border-radius:40px;
    border-radius:40px;
    overflow:hidden;
    position:absolute;
}
video{
    width:320px;
    -moz-border-radius:40px;
    -webkit-border-radius:40px;
    border-radius:40px;
    overflow:hidden;
}