exact resolution for course presentation

Hi there,

we have not been able to determine the exact resolution or aspect ratio of the course presentation. Even if we distort the cover page to fill the entire window, a fine white line remains on the left and bottom.  

Uploading videos in H5P is accompanied by the black bars of the video window. Is there a way to fix this?

Furthermore the slide in 960x620 appears blurred. On another slide the picture was uploaded in a resolution of 2339x1654. But this results in a strong demand (partial overstraining) of the Power-Points program. Is there a slide size (exported as png/jpg) that you can recommend?

Thanks in advance.

Best
Steffi