Hello, I have found a problem and a workaround, that I think the (dev) community should know about.
The problem:
I have created a Layout with 2 regions. Each of these regions displays the same video in a loop, and nothing else. When I start the player, the videos are correctly shown for (in most cases) 2 loop iterations. After that, the default Layout starts playing and the Error message “Open not called after 4 seconds, marking unsafe and Expiring.” is logged.
I have read much about this and it probably has something to do with player performance and that 4 second video load timeout.
The workaround:
After trying several things to fix my problem, I tried adding spacer widgets before the videos. Now I have the exactly same layout as before, but the playlists for both regions start with a 1 second spacer instead of directly showing the video. And suddenly the problem is gone. Of course, this adds 1 second until the video starts, but that is still better than having the layout break after 2 loop cycles.
I hope this workaround helps someone else in the future or is interesting to the devs.
