Video Element and Video-Slider Problem

Hi there,

I used the following fix to display my videos:

#top .av-video-slide video {
height: auto !important;
}
#top .av-video-slide .mejs-container {
width: 100% !important;
}

.avia-video .mejs-container, div .avia-video .mejs-container video {
width: 100% !important;
}

.mejs-controls .mejs-offscreen, .mejs-button, .mejs-time-rail {
display: none;
}

But I still have some issues I would appreciate your help.
This is the page. I am talking about the video right at the top of the page below the logo:

First problem:
On large Screens (wider than 990px – eg: Desktop), I use the “Slide-show (volle Breite) Element. After the fix above, the video is playing but the lower part is cut off. I need it vertically centered..

Second Problem:
On smaller Screens I use the regular Video-Element and the Video isn’t showing at all. What can I do?

Third Problem:
On Safari is no video at all.

Thank you very much,
Axel