I have 2 problems with KODI, please help

Hello guys, I am trying out KODI since the last 2 days and I really like it but I am facing 2 problems which I hope you can help me with.
My first question would be, how can I play KODI in an external player for example ACE Player or VLC Player? I was already trying out things but the most what I did reach was, choosing VLC Player via pressing y on keyboard but when it opens VLC Player there is only Sound no Image. Can someone of you please help me with a working .xml for ACE Player or VLC Player and how I can get it activated properly? I would really appreciate it.

My second problem is the screen while playing a channel or any video with KODI. I don’t know how to explain it but there are like huge lines on the screen on different positions like a broken mirror (?). The quality itself is sharp but the line are shaky and that is what annoys me. Is there any solution for this problem?

Sorry for my not so good english, I hope you can still understand what my text Big Grin

Hope you have a great day..