JSFiddle - React, Tailwind, and code Playground

HTML

<div class="outer">
    <video src="http://www.w3schools.com/html/movie.ogg" type="video/ogg" controls></video>
</div>

CSS

div.outer {
    float: left;
    height: 240px;
}
div.outer video {
    width: 320px;
    height: 100%;
    -webkit-mask-image: url(data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAIAAACQd1PeAAAAGXRFWHRTb2Z0d2FyZQBBZG9iZSBJbWFnZVJlYWR5ccllPAAAAA5JREFUeNpiYGBgAAgwAAAEAAGbA+oJAAAAAElFTkSuQmCC);
    border-radius: 32px 0 32px 0;
}