Iframe video size IE probelm



I will expose my little problem.

I have an iframe in which I insert a URL of a video.
The size of it is displayed correctly everywhere except on ie9.

The normal size of my video is 640/480 but in ie9 225/175, this problem:)

my code :

    <iframe width="640" height="480" frameborder="0" scrolling="no" src="http://api.dmcloud.net/player/embed/4d7e0c4ff325e16fc5002069/52b958c594a6f659ba6c92c5?auth=1703238714-0-dvpl98mu-b880620503c45804e52a6aadad58deb9&autoplay=1"></iframe>