title: Green screen in WPF
body: <p>We have a video that we need to show in a button, but we want the background of the button to show, and we can't put the background in the video because the button can change the size, and the background needs to stretch to the size of the button, but not the video. The video has to keep its size ratio, so I'm wondering if there is a way to do something like a green screen in WPF, so we can put a green background on the video, and have the button ignore it to show its own background.</p>
  
  <p>I know this is a long shot but any suggestion is very welcome.</p>
  
  <p>Thanks!</p>