<link href="//maxcdn.bootstrapcdn.com/bootstrap/4.0.0/css/bootstrap.min.css" rel="stylesheet" id="bootstrap-css"> <script src="//maxcdn.bootstrapcdn.com/bootstrap/4.0.0/js/bootstrap.min.js"></script> <script src="//code.jquery.com/jquery-1.11.1.min.js"></script> <!------ Include the above in your HEAD tag ----------> <div class="container"> <div class="row"> <div class="col-12 text-center"><h1>Responsive video</h1></div> <div class="col py-2"> <div class="video"><iframe src="https://www.youtube.com/embed/AWdA7hdP4ZA?rel=0&showinfo=0" frameborder="0" allowfullscreen></iframe></div> </div> <div class="col py-2"> <div class="video"><iframe src="https://www.youtube.com/embed/I39RKjerJss?rel=0&showinfo=0" frameborder="0" allowfullscreen></iframe></div> </div> <div class="col py-2"> <div class="video"><iframe src="https://www.youtube.com/embed/Dkx4LYeFnVY?rel=0&showinfo=0" frameborder="0" allowfullscreen></iframe></div> </div> </div> </div>

.video { height: 0; position: relative; padding-bottom: 56.25%; /* Если видео 16/9, то 9/16*100 = 56.25%. Также и с 4/3 - 3/4*100 = 75% */ } .video iframe { position: absolute; left: 0; top: 0; width: 100%; height: 100%; }