Hi

I have this very strange problem. Video playback makes my 4K screen go black for 2-4 sec. randomly while playing. Now the strange thing is, when I play video (1080p/4K) in full screen mode via the "Video player" that is installed on Ubuntu by default, and KDENLIVE, the screen randomly goes black for 2-4 sec. (happens all the time). What is going on? I have never had this issue before, but it started about a month ago. I have 3 monitor setup, and it ONLY happens to the 4K monitor, not the other 1080p monitors.

My setup:

AMD Ryzen7 2700X, XFX RX580, 3 monitors connected (1x4K via DisplayPort @ 60Hz, 2x1080p via DVI), AMDGPU default driver installed by Ubuntu.

Try different cables, or swapping them between monitors. Some may not like or be able to handle 4k video, even if rated for it, or perhaps is faulty. I am overseas and I brought an HDMI cable with me that I thought was one I had been using at home for 4k , but I had to get another one as it did exactly what you see - random blanking at that resolution. Different cable = no more issue.