I couldn't fix the problem. I seen that the channels / signals are recognized as 25.000 fps from the Formuler Box. I assume that is why i'm getting stutter on a 50 FPS resolution such as 4K 50 Hz.
In my other app the channels are detected as 50 FPS so the picture is very smooth....
If i change the box to 4K 25HZ obviously its not enjoyable to watch.