Problem when adjusting the height of a carousel

I have a carousel in Bootstrap 4 the images I load measure 980,500 px and I have a defined style with these parameters

.carousel-inner img {
      object-fit: scale-down;
      height: 500;
      width: 980;
      background-color: black;
}

The images are loaded perfectly in the mobile but in the browser I have the problem that the height of the carousel occupies almost the entire screen. I need that background does not exceed the height of the images Or at least 510 pixels so I left a kind of "frame" to the images ... Can someone give me a hand ?