Youtube

<div class="embed-responsive embed-responsive-16by9">
  <iframe class="embed-responsive-item" src="https://www.youtube.com/embed/zpOULjyy-n8?rel=0" allowfullscreen></iframe>
</div>

Vimeo

<div class="embed-responsive embed-responsive-16by9">
  <iframe class="embed-responsive-item" src="https://player.vimeo.com/video/644036051?&title=0&byline=0&portrait=0" allowfullscreen></iframe>
</div>