embedユーティリティは、<iframe>要素と_.embed-responsive_クラスおよびアスペクト比（たとえば、embed-responsive-21by9）を使用して、ページにビデオを挿入するために使用されます。
21by9 _、 16by9 、 4by3 _、1by1などのアスペクト比を使用して、ページにビデオを埋め込むことができます。 次の例はこれを示しています-
<html lang = "en">
<head>
<!-- Meta tags -->
<meta charset = "utf-8">
<meta name = "viewport" content = "width = device-width, initial-scale = 1, shrink-to-fit = no">
<!-- Bootstrap CSS -->
<link rel = "stylesheet"
href = "https://maxcdn.bootstrapcdn.com/bootstrap/4.1.3/css/bootstrap.min.css">
<script src = "https://ajax.googleapis.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<title>Bootstrap 4 Example</title>
</head>
<body>
<div class = "container">
<h2>Aspect Ratios</h2>
<h4>21:9 aspect ratio</h4>
<div class = "embed-responsive embed-responsive-21by9">
<iframe class = "embed-responsive-item"
src = "https://www.youtube.com/embed/I_G0Yb6R7m0" allowfullscreen></iframe>
</div>
<br>
<h4>16:9 aspect ratio</h4>
<div class = "embed-responsive embed-responsive-16by9">
<iframe class = "embed-responsive-item"
src = "https://www.youtube.com/embed/I_G0Yb6R7m0"></iframe>
</div>
<br>
<h4>4:3 aspect ratio</h4>
<div class = "embed-responsive embed-responsive-4by3">
<iframe class = "embed-responsive-item"
src = "https://www.youtube.com/embed/I_G0Yb6R7m0"></iframe>
</div>
<br>
<h4>1:1 aspect ratio</h4>
<div class = "embed-responsive embed-responsive-1by1">
<iframe class = "embed-responsive-item"
src = "https://www.youtube.com/embed/I_G0Yb6R7m0"></iframe>
</div>
</div>
<!-- jQuery first, then Popper.js, then Bootstrap JS -->
<script src = "https://code.jquery.com/jquery-3.2.1.slim.min.js"
integrity = "sha384-KJ3o2DKtIkvYIK3UENzmM7KCkRr/rE9/Qpg6aAZGJwFDMVNA/GpGFF93hXpG5KkN"
crossorigin = "anonymous">
</script>
<!-- Popper -->
<script src =" https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.12.9/umd/popper.min.js"
integrity =" sha384-ApNbgh9B+Y1QKtv3Rn7W3mgPxhU9K/ScQsAP7hUibX39j7fakFPskvXusvfa0b4Q"
crossorigin = "anonymous">
</script>
<!-- Latest compiled and minified Bootstrap JavaScript -->
<script src = "https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/js/bootstrap.min.js"
integrity = "sha384-JZR6Spejh4U02d8jOt6vLEHfe/JQGiRRSQQxSfFWpi1MquVdAyjUar5+76PVCmYl"
crossorigin = "anonymous">
</script>
</body>
</html>それは次の結果を生成します-
