Responsive is kind of working for me.
Width sets itself fine, but height is where my issues lie. Once it gets to around mobile size, it stops scaling the height and sets it to a huge height, usually overlapping content. I saw that it was taking the height still from the defaults, so I set that to 235 and it made no difference.
Also, when I set |autoplay after the youtube vid name, it puts autoplay in the width field in the page source code.
Please see the attached image, you can see the actual video is correct size, but the black area should have scaled down as well?