Com o código abaixo você consegue inserir um vídeo iframe centralizado, em formato quadrado.
<style>
.square-box {
position: relative;
padding-bottom: 100%; /* 1:1 */
height: 0;
width: 100%;
overflow: hidden;
}
.threebytwo-box {
position: relative;
padding-bottom: 66.66%; /* 3:2 */
height: 0;
width: 100%;
overflow: hidden;
}
.widescreen {
position: absolute;
padding-bottom: 100%; /* 16:9 * 9:16 ?? */
height: 0;
left: 50%;
top: 50%;
width: 177.78%; /* 9:16 */
transform: translate(-50%, -50%);
}
.widescreen2 {
position: absolute;
height: 0;
left: -38.88%;
right: -38.88%;
}
.square-box .widescreen2 {
padding-bottom: 100%; /* 1:1 ?? */
left: -38.88%;
right: -38.88%;
}
.threebytwo-box .widescreen2 {
padding-bottom: 66.666%; /* 3:2 ?? */
left: -9.25%;
right: -9.25%;
}
iframe {
left:0;
top:0;
height: 100%;
width: 100%;
position: absolute;
}
</style>
<div class="square-box">
<div class="widescreen">
<iframe style="" src ="CODIGOIFRAME" width="100%" height="auto" scrolling="no" style="border:none;" sandbox="allow-scripts allow-presentation allow-same-origin" allow="autoplay; xr-spatial-tracking; encrypted-media; transparency" playsinline class="nolazy"></iframe>
</div>
</div>