DIV video background problems

[bravewart]

I am trying to use a video background (Vimeo iframe) in a DIV, but I cannot get it to fill out the DIV as I want to save my life.
I am working from an HTML template and I am an intermediate user at the most.
here is a screen capture of what it is doing at the moment when I scale the browser window to check responsiveness: DIV scaling. (the video content almost looks like a still picture, but it's in fact a moving video)

What I am trying to do is: The video should be locked to the bottom right corner of the DIV. The left OR the top side of the video should be cropped, depending on the aspect ratio of the DIV.

Why am I not getting this? I first thought that it might not be such a big deal, but it just won't work.

could anybody help me with this?

here is the HTML of the DIV:
 

<div class="imageblock__content videobg col-lg-6 col-md-4 pos-right" data-overlay="0">
	<iframe src="https://player.vimeo.com/video/372864200?background=1" style="position:relative;right:0%;bottom:0%;width: 120%; overflow:hidden" frameborder="0" allow="autoplay; fullscreen" allowfullscreen></iframe>
    <div class="background-image-holder"> <img alt="image" src="img/wedding-5.jpg"> </div>
</div>

and here are all the relevant CSS calls:

.videobg .container,
.videobg .background-image-holder {
  opacity: 0;
  transition: 0.3s linear;
  -webkit-transition: 0.3s linear;
  -moz-transition: 0.3s linear;
}
.videobg .background-image-holder {
  opacity: 0 !important;
}
.videobg.video-active .container {
  opacity: 1;
}
.videobg.video-active .loading-indicator {
  opacity: 0;
  visibility: hidden;
}
.videobg video {
  object-fit: cover;
  height: 100%;
  min-width: 100%;
  position: absolute;
  top: 0;
  z-index: 0 !important;
  left: 0;
}
@media all and (max-width: 1024px) {
  .videobg .background-image-holder,
  .videobg .container {
    opacity: 1 !important;
  }
  .videobg .loading-indicator {
    display: none;
  }
  .videobg video {
    display: none;
  }
}
.imageblock .imageblock__content {
  position: absolute;
  height: 100%;
  top: 0;
  z-index: 2;
  padding: 0;
}
.col-lg-6 {
    flex: 0 0 50%;
    max-width: 50%; }
 .col-md-4 {
    flex: 0 0 33.3333333333%;
    max-width: 33.3333333333%; }
.pos-right {
  right: 0;
}