Add a new Html/text layer in Slider Revolution and paste the following shortcode inside the content box (click the pencil icon):
<a href="https://www.youtube.com/watch?v=XngVB1sRvsU"><img src="http://www.mywebpage.com/wp-content/uploads/2016/07/button-video.svg"></a>
Replace your video ID and button image in the shortcode above. I used the button graphic in .svg format, but it could be .png or .jpg. Works like a charm 🙂