<div class="embed-responsive embed-responsive-16by9 mb-3">
<iframe class="embed-responsive-item" src="https://www.youtube.com/embed/ZDf5hRFwg6w"></iframe>
</div>
<div class="embed-responsive embed-responsive-16by9 mb-3">
<iframe class="embed-responsive-item" src="{{ src }}"></iframe>
</div>
{
"src": "https://www.youtube.com/embed/ZDf5hRFwg6w"
}
Aspect ratios can be customized with modifier classes.
<!-- 21:9 aspect ratio -->
<div class="embed-responsive embed-responsive-21by9">
<iframe class="embed-responsive-item" src="..."></iframe>
</div>
<!-- 16:9 aspect ratio -->
<div class="embed-responsive embed-responsive-16by9">
<iframe class="embed-responsive-item" src="..."></iframe>
</div>
<!-- 4:3 aspect ratio -->
<div class="embed-responsive embed-responsive-4by3">
<iframe class="embed-responsive-item" src="..."></iframe>
</div>
<!-- 1:1 aspect ratio -->
<div class="embed-responsive embed-responsive-1by1">
<iframe class="embed-responsive-item" src="..."></iframe>
</div>