Vimeo embed and resize issues

I am trying to embed a Vimeo video in a simple post and use the autoplay option.
Using the embed video button this is the shortcode I get : [av_video src='https://vimeo.com/73961982' format='16-9' width='16' height='9']
This way the size of the video works fine and resizing too but adding autoplay=1 won’t work as this option only works using the embed code provided by vimeo where includes the iframe block.
In order to autoplay the video I can only use this code :<iframe src=”//player.vimeo.com/video/73961982?autoplay=1″ width=”500″ height=”281″ frameborder=”0″></iframe>
The problem with this code is that the size of the video is not the proper one (I have the black columns on the sides). Is there a way to change width=”500″ height=”281″ to format=’16-9′ width=’16’ height=’9′ so I can get the same results with the size ? I guess “format=16-9” is a special parameter from avia builder.
How can get something like this [av_video src='https://vimeo.com/73961982?autoplay=1' format='16-9' width='16' height='9'] but using iframe so the autoplay works properly ?
Thanks a lot.