I had this problem and fixed it by setting the background-color css property of the html5 video element to 'transparent'.
By default it is styled to black (rgb(0,0,0)) which causes the black lines to appear in some browsers.
In your css you need to apply the following style to any video element nested within your krpano div.
CSS
video {
background-color: transparent !important;
}Although this is an old post I thought this reply may help other users who have this problem...
