With Kubuntu 15.04 and Digikam 4.13.0, Libkipi 2.2.0, videos can be viewed as preview (click in thumbnail), but not in a slideshow. During the slideshow, only a black screen is shown instead of the video. But in e.g. vlc, mp4 videos in slideshow is no problem. What is to do, to show mp4 vidoes in a slideshow with digikam?