How to resize a video to fit within a specific area without losing the original aspect ratio?

Question

Basically I have a non-resizable rectangle with a set width and height. I need to resize the video to fit within that rectangle without losing the original aspect ratio (which I'm calculating as width/height). Thank you for your help!

Answer 1

That would mess up the aspect ratio and make the video look stretched. Not the behavior I'm looking for.

Answer 2

try this in css
video{
width:500px;
height:auto;
}