Video ratio wrongly display in player

hi all,

i've installed kaltura to my drupal. i set my player to keep the original ratio of the video cotent, in Kaltura Media Node Settings->Video Display

before i click the play button, the image remains in it's original ratio, but when i click play button, the video stretches to fit the player box.

when i click full screen, it stretches too.

can any one give me some tips on this?

thanks